Vegetable IPM Reports

Hello vegetable IPM folks!

As fields are harvested and pest pressure decreases with the cooling temperatures, we will be reporting from less locations.

Corn earworm catches have more than doubled from last week with the weekend storms bringing moths north. We have a few locations on a 4-day spray schedule. Our trap threshold/spray schedule table can be found in this fact sheet, along with those for FAW. Fall armyworm numbers are like last week. Six locations are still at or over threshold for silking corn (3+ moths/week). FAW prefers the youngest stage corn that is available. The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. Note that only corn earworm and fall armyworm numbers are included. We caught 0 European corn borer this week.

Table 1. Sweet corn pest weekly summary, 9/6-9/12/2025. 

Three squash vine borer moths were caught this week in Milford. We are still monitoring for a 2^nd generation. Our UNH Extension fact sheet is a great resource for this pest. 

Spotted wing drosophila numbers remain high in controls and raspberries but have decreased overall from last week due to the cooler temperatures. Blueberry traps have been pulled for the season. Yellowjackets have been more prevalent in fruit crops this year, likely due to the drought and the moisture/sugar source provided by berries. SWD male captures by crop are shown in Table 2 below. The control traps are located in unmanaged areas surrounding fields and may have more SWD than reported. 

Table 2. Total male SWD captures by crop, 9/8-9/12/2025.  

Brown marmorated stink bug captures have increased again. We generally see higher numbers in dry weather and later in the season. Both nymphs and adults can damage crops. In NH, BMSB is more of a nuisance pest but can cause damage to agricultural crops, including tomatoes and tree fruit. Be on the lookout if you have tomatoes and peppers near edge habitats. Captures by location are shown in Table 3 below.

Table 3. BMSB weekly summary, 9/8-9/12/25.

Miscellaneous pest information: 

• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports

Disease of the Week:  

Let’s discuss harvesting pumpkins, squashes, and gourds! As previously discussed, correct harvesting and storing greatly reduces the likelihood of a post-harvest disease and loss in storage. This Cornell fact sheet and the New England Vegetable Management guide have great information about maturity, harvest, and storage of winter squash and pumpkins.

Something that is key to remember as we are getting cooler nights is that fruits should not be exposed to 32º F, as this can promote storage problems. If possible, pumpkins that have reached full color should be stored under cover to protect them from chilling injury from temperatures below 50º F and from disease.

There are many post-harvest diseases that can infect squashes and pumpkins (you may see some similarities to last week’s list): Black rot (Didymella bryoniae), Fusarium Rot (Fusraium solani f.sp. cucurbitae), Phyopthora Fruit Rot (Phytophthora capsici), Anthracnose (Colletotrichum orbiculare), Alternaria Rot (Alternaria alternata), Bacterial Soft Rot (Pectobacterium and Dickeya spp.), and Gray Mold (Botrytis cinerea). An important note is that growers may see sun scald on their fruit due to the high temperatures that we had this summer and potentially low canopy cover. This may look similar to post-harvest disease symptoms.

The best management options are to prevent injuries during harvest – these wounds and bruises can be entry points for diseases such as Fusarium, Alternaria, and bacterial rots. Curing and proper storage temperature and humidity will greatly decrease disease and the potential spread of disease.

While there are some fungicide options available for managing these diseases, they would have needed to be applied during the growing season. So, if you have issues with any of these diseases, keep note, and we can make a plan for management for next year!

Other information of note: 

• Drought resources: Guide to Drought Management for NH Growers and US Drought Monitor.
• Water use and food safety! UNH Extension Food Safety State Specialist, Wendy Johnecheck, recently published a blog about Water Use on Produce Farms: A Focus on Food Safety. This is a great refresher and/or resource for requirements and recordkeeping related to FSMA.
• New pesticide safety resources! UNH Extension Pesticide Safety Education Field Specialist, Rachel Maccini, has recently shared a few blog posts that may be helpful. The links and more information can be found below.
  • Safe and Responsible Pesticide Disposal: What to Do with Unused Products
  • Why Checking Pesticide Registration in New Hampshire Matters
  • Pesticide Labels: I Need a New One
  • Introducing Denyce Gagne, new Enforcement Program Manager for Pesticide Control

Rachel also wrote a new article on pesticide efficacy and drought conditions which can be found here. 

The EPA released a new app to help with pesticide label mitigations. More information can be found here. 

• Soil pH and nutrient management! UNH Extension Soil Heath State Specialist, Renuka Mathur, put together some information on soil pH and how that impacts nutrient availability. See the Veg IPM Report from 8.15.25 for more information.

Upcoming events: 

• 2025 North Country Farm & Homestead Conference
  October 15, 2025 | 9:00am - 3:00pm
  516 Main Street, Lancaster Fair Grounds, Lancaster, NH 
  
  Join us for a day of learning, hands-on demonstrations, and community at the North Country Farm & Homestead Conference! Whether you're a homesteader, small-scale farmer, or aspiring grower, this event offers a mix of concurrent sessions and live demonstrations designed to help you build skills, improve your land, and strengthen your operation. From soil health and cover cropping to backyard livestock, beekeeping, and variety trials, you'll gain practical, real-world knowledge tailored to small-scale and diversified farming. Enjoy hands-on activities like chainsaw maintenance, tractor safety, shiitake log inoculation, alongside insightful discussions on food preservation. With opportunities to network with experts, explore the trade show, and share experiences with fellow growers! Cost: $30/person. Registration closes: October 7, 2025. Register and find more information here!
• High Tunnel Production Conference: Enhance Your Tunnel Vision
  December 10, 2025 | 9:00am - December 11, 2025 | 4:00pm
  Fireside Inn and Suites, 25 Airport Road, West Lebanon, NH 
  
  Calling all high tunnel growers! Whether you are a new or experienced high tunnel grower, plan to join UMaine, UNH, and UVM for this two-day event. Come learn from experts and other farmers, talk with vendors, and see their products at the trade show.  This conference will offer useful information for high tunnel growers and agricultural service providers of all experience levels and all crops. Cost is $120 for both days.* Registration fee includes the farm tour, all educational sessions, admission to the trade show, and lunch on Day 2. *Additional people from the same farm are just $90 each. Registration deadline is December 3. Find more information about the program and register here!

Reminder--The University of New Hampshire Plant Diagnostic Lab has temporarily suspended its services for the remainder of 2025. In the meantime, please refer to Extension's Plant Diagnostics webpage for a list of labs who have agreed to provide diagnostic services in the interim. Please note that soil analysis, insect identification, and tick testing services remain fully operational. We apologize for any disruptions caused by the temporary closure of the Plant Diagnostic Lab. We will provide updates regarding a reopening plan as it is finalized. 

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010. 

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program!  

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture.  

Hello vegetable IPM folks!

I hope harvest season is going well for everyone despite the lack of water.

We caught 0 European corn borer this week. We captured 1 western bean cutworm in Hollis, indicating the end of WBC for 2025.

Corn earworm catches have decreased, with a few locations on a 5- or 6-day spray schedule. Our trap threshold/spray schedule table can be found in this fact sheet, along with those for ECB and FAW.

Fall armyworm numbers have also decreased since last week. Six locations are still over threshold for silking corn (3+ moths/week). Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement. FAW prefers the youngest stage corn that is available.

The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town.  Note that only corn earworm and fall armyworm numbers are included.

Table 1. Sweet corn pest weekly summary, 8/30-9/5/2025. 

Only 2 squash vine borer moths were caught this week—one in Litchfield and one in Hollis. We are still trapping to monitor for a 2^nd generation. Our UNH Extension fact sheet is a great resource for this pest.

Spotted wing drosophila numbers remain high and similar to last week, with increases in grape and control traps. If you have susceptible ripening fruit, monitor for SWD and apply management as needed. More information on monitoring for SWD can be found here. Frequent harvesting and placing harvested berries in the fridge can help slow SWD development within the fruit. This resource from Cornell on SWD management includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 2 below.The control traps are located in unmanaged areas surrounding fields and may have more SWD than reported. 

Table 2. Total male SWD captures by crop, 9/1-9/5/2025.  

Brown marmorated stink bug captures have increased again. We generally see higher numbers in dry weather and later in the season. Both nymphs and adults can damage crops. Anna Wallingford recorded a podcast on BMSB that can be found here. You can also read through the transcript rather than listen if that is preferred. In NH, BMSB is more of a nuisance pest but can cause damage to agricultural crops, including tomatoes and tree fruit. Be on the lookout if you have tomatoes and peppers near edge habitats. Captures by location are shown in Table 3 below. There are currently no treatment thresholds for BMSB and vegetables but research in the Northeast is ongoing. For those who also grow tree fruit, insecticide applications are recommended for apples using a threshold of 10+ adult BMSB/trap. The threshold is reset after each insecticide application until the 10 adults/trap threshold is reached again to trigger another insecticide spray. This threshold can also be used for peaches. More information can be found in the New England Tree Fruit Management Guide.

Table 3. BMSB weekly summary, 9/1-9/5/25.

Miscellaneous pest information: 

• For those of you that experienced hail last week, here is a resource from Purdue University on hail damage to vegetables. Disease management is important after hail, be sure to check fungicide labels for use in New Hampshire and cull damaged fruit for certain crops. Defoliation from hail can also expose fruit to sunburn. Some crops recover better than others.
• Cabbage root maggot information can be found in the Vegetable IPM Report from 8.8.25. This is a pest to look out for if you have fall brassicas and the weather is especially cool and wet.
• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports

Disease of the Week:  

Over the next couple of weeks, we will focus on post-harvest rots and tools for preventing them as you get through harvest. Post-harvest diseases are those that present symptoms once the crop is already harvested and in storage, however, there are times when the infection can occur in the field prior to harvest.

Let’s focus on ONIONS this week. Some common post-harvest diseases of onions are Botrytis Neck Rot (caused by Botrytis allii), Bacterial Soft Rot (caused by Erwinia carotovora), Fusarium Basal Rot (caused by Fusarium oxysporum f. sp. cepae), Purple Blotch (caused by Alternaria porri), White Rot (caused by Sclerotium cepivorum), and the more ubiquitous fungal diseases of stored fruits and vegetables: Blue mold (Penicillium sp.) and Black mold (Aspergillus niger).

While these various diseases represent both fungal and bacterial pathogens, there are things that can be done to prevent onion post-harvest diseases of all kinds. Good cultural control options are key to preventing disease: disease-free seed, resistant cultivars, not applying nitrogen fertilizer later than ~8-9 weeks after seeding, proper spacing of onions, removing plant debris at end of season, allowing tops to mature, and minimizing injury (either insect or mechanical).

Finally proper undercutting, curing, and storage are key to preventing post-harvest diseases of onions. Making sure that you are using the proper techniques and environmental parameters will keep your onions viable and disease free. This quick video out of UMaine Extension is a great review of harvesting and storing onions: https://extension.umaine.edu/food-health/food-preservation/how-to-videos/how-to-harvest-and-store-onions/#

While there are some fungicide options available for managing these diseases, they would have needed to be applied during the growing season. So, if you have issues with any of these diseases, keep note, and we can make a plan for management for next year!

Other information of note: 

-Drought resources: Guide to Drought Management for NH Growers and US Drought Monitor.

-Water use and food safety! UNH Extension Food Safety State Specialist, Wendy Johnecheck, recently published a blog about Water Use on Produce Farms: A Focus on Food Safety. This is a great refresher and/or resource for requirements and recordkeeping related to FSMA. 

-New pesticide safety resources! UNH Extension Pesticide Safety Education Field Specialist, Rachel Maccini, has recently shared a few blog posts that may be helpful. The links and more information can be found below.

• Safe and Responsible Pesticide Disposal: What to Do with Unused Products
• Why Checking Pesticide Registration in New Hampshire Matters
• Pesticide Labels: I Need a New One
• Introducing Denyce Gagne, new Enforcement Program Manager for Pesticide Control

Rachel also wrote a new article on pesticide efficacy and drought conditions which can be found here.

The EPA released a new app to help with pesticide label mitigations. More information can be found here.

-Soil pH and nutrient management! UNH Extension Soil Heath State Specialist, Renuka Mathur, put together some information on soil pH and how that impacts nutrient availability. See the Veg IPM Report from 8.15.25 for more information.

Upcoming events: 

-2025 North Country Farm & Homestead Conference
October 15, 2025 | 9:00 a.m. - 3:00 p.m.
516 Main Street, Lancaster Fair Grounds, Lancaster, NH

Join us for a day of learning, hands-on demonstrations, and community at the North Country Farm & Homestead Conference! Whether you're a homesteader, small-scale farmer, or aspiring grower, this event offers a mix of concurrent sessions and live demonstrations designed to help you build skills, improve your land, and strengthen your operation. From soil health and cover cropping to backyard livestock, beekeeping, and variety trials, you'll gain practical, real-world knowledge tailored to small-scale and diversified farming. Enjoy hands-on activities like chainsaw maintenance, tractor safety, shiitake log inoculation, alongside insightful discussions on food preservation. With opportunities to network with experts, explore the trade show, and share experiences with fellow growers! Cost: $30/person. Registration closes: October 7, 2025. Register and find more information here!

-High Tunnel Production Conference: Enhance Your Tunnel Vision
December 10, 2025 | 9:00 a.m. - December 11, 2025 | 4:00 p.m.
Fireside Inn and Suites, 25 Airport Road, West Lebanon, NH

Calling all high tunnel growers! Whether you are a new or experienced high tunnel grower, plan to join UMaine, UNH, and UVM for this two-day event. Come learn from experts and other farmers, talk with vendors, and see their products at the trade show. This conference will offer useful information for high tunnel growers and agricultural service providers of all experience levels and all crops. Cost is $120 for both days.* Registration fee includes the farm tour, all educational sessions, admission to the trade show, and lunch on Day 2. *Additional people from the same farm are just $90 each. Registration deadline is December 3. Find more information about the program and register here!

Reminder--The University of New Hampshire Plant Diagnostic Lab has temporarily suspended its services for the remainder of 2025. In the meantime, please refer to Extension's Plant Diagnostics webpage for a list of labs who have agreed to provide diagnostic services in the interim. Please note that soil analysis, insect identification, and tick testing services remain fully operational. We apologize for any disruptions caused by the temporary closure of the Plant Diagnostic Lab. We will provide updates regarding a reopening plan as it is finalized.

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010.

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program! 

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture.  

Hello vegetable IPM folks!

For those of you that experienced hail on Wednesday, here is a resource from Purdue University on hail damage to vegetables. Disease management is important after hail, be sure to check fungicide labels for use in New Hampshire and cull damaged fruit for certain crops. Defoliation from hail can also expose fruit to sunburn. Some crops recover better than others.

We caught 6 European corn borer moths this week in western NH. Click HERE for more information on ECB management.

Corn earworm catches have increased, with a few locations on a 4-day spray schedule and many others on a 5–6-day schedule. If you have silking corn, be sure to scout for CEW and prepare for management. Our trap threshold/spray schedule table can be found in the fact sheet linked below, along with those for ECB and FAW. CEW eggs hatch in 2-5 days depending on temperature and newly hatched larvae move down the silk into the ears quickly. Insecticide control of CEW requires good protective coverage of the ear zone so that when the eggs hatch, the young larvae will immediately contact a lethal dose of insecticide.

A note on corn earworm insecticide resistance: Rotate chemical classes to delay resistance development and help mitigate pyrethroid (Group 3) resistance that may be occurring in the southern US. It’s best to avoid spraying pyrethroids more than twice in a row. New England faces unique challenges in managing insecticide resistance for CEW. The moths are migrating from the southern US, where they were likely already exposed to pesticides and we get new populations every year with varying degrees of resistance. We are also experiencing warmer temperatures and the potential for more pests overwintering in NH that have not historically overwintered here. We also have limited options for insecticide modes of action, some of which may be cost-prohibitive. Continue monitoring moths and insecticide efficacy in controlling CEW. Please let us know if you are no longer seeing control with products that have controlled CEW in the past.

Fall armyworm numbers have increased since last week. Most locations are still over threshold for silking corn (3+ moths/week). Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement. FAW is likely to be controlled with a tighter spray schedule for CEW, but if you are using a longer spray interval for CEW, or don’t need to spray for CEW, continue to scout fields for FAW and implement controls if >15% are infested (silk) and >30% (whorl-silk). FAW prefers the youngest stage corn that is available.

Our scout observed 0-5% damage to sweet corn this week from insects depending on location, averaging 2.5% damage across scouted fields. Field scouting should begin once moths are captured at your farm or in your area. Threshold information for the sweet corn caterpillars can be found here.

Western bean cutworm captures are close to zero, indicating the end of WBC for 2025. We generally see this pest increase quickly, hitting its peak in late July, and then decreasing rapidly in early August. This summer, WBC did not decrease rapidly, and we observed an extended population peak.

The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town. 

Table 1. Sweet corn pest weekly summary, 8/23-8/29/2025. ECB #s are combined IA and NY.

Squash vine borer numbers remain low and similar to last week, with no locations over threshold. I have had reports of active adults and boring holes from larvae in the northern part of NH and of larvae burrowing into pumpkin fruit in the southeastern region. Our UNH Extension fact sheet is a great resource for this pest. 

Table 2. Squash vine borer weekly summary, 8/23-8/29/2025.  

Spotted wing drosophila numbers are high and similar to last week, with increases in blueberry and raspberry fruit traps. If you have susceptible ripening fruit, monitor for SWD and apply management as needed. More information on monitoring for SWD can be found here. Frequent harvesting and placing harvested berries in the fridge can help slow SWD development within the fruit. This resource from Cornell on SWD management includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 3 below.The control traps are located in unmanaged areas surrounding fields and may have more SWD than reported. 

Table 3. Total male SWD captures by crop, 8/25-8/29/2025.  

Brown marmorated stink bug captures have decreased. We generally see higher numbers in dry weather and later in the season. Both nymphs and adults can damage crops. Anna Wallingford recorded a podcast on BMSB that can be found here. You can also read through the transcript rather than listen if that is preferred. In NH, BMSB is more of a nuisance pest but can cause damage to agricultural crops, including tomatoes and tree fruit. Captures by location are shown in Table 4 below. There are currently no treatment thresholds for BMSB and vegetables but research in the northeast is ongoing. For those who also grow tree fruit, insecticide applications are recommended for apples using a threshold of 10+ adult BMSB/trap. The threshold is reset after each insecticide application until the 10 adults/trap threshold is reached again to trigger another insecticide spray. This threshold can also be used for peaches. More information can be found in the New England Tree Fruit Management Guide. 

Table 4. BMSB weekly summary, 8/25-8/29/25.

Miscellaneous pest information: 

• Leafhoppers were observed feeding on basil in northern NH this week. Leafhopper nymphs can be found on the underside of leaves and controlled similarly to aphids and whiteflies. Check labels for crops and pests. Row covers may also help exclude leafhoppers. 

• Mexican bean beetles are pests of beans. Adults are copper-colored ladybeetles and larvae are yellow with rows of spines. The adults overwinter in hedgerows and move into fields in June. Feeding from adults and larvae skeletonizes leaves and can cause damage to pods if pressure is high. MBB has 1-3 generations per year in New England, and pressure is usually worse in areas with successive bean plantings. Damage is usually not significant until August. Destroy crop residue after harvest to help reduce the overwintering population. Scout plants for all stages of MBB and assess damage. If Mexican bean beetles are a problem on your farm, information on chemical management can be found in the New England Vegetable Management Guide. 

• Diamondback moth and imported cabbageworm are both caterpillar pests of brassica crops. Young DBM larvae will not chew all the way through the leaf, leaving “windowpane” holes with translucent layers of leaf tissue. They are green and segmented and look pointed at both ends. Most DBM moths arrive with storms, though we believe they do overwinter in New England in warm areas and high tunnels, or if we have a mild winter. ICW are larger than DBM, green and velvety looking. Their feeding causes large irregular holes in leaves, and they leave behind messy frass. They will also feed in the heads of brassica crops. The adults are cabbage white butterflies. See photo below for an ICW larvae and chrysalis (pupa). More information on DBM can be found here. See our Vegetable IPM Report from 6.23.25 for more information on ICW. 

Imported cabbageworm larva (left) and chrysalis/pupa (right). 

• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports

Other information of note: 

-Drought resources: Guide to Drought Management for NH Growers and US Drought Monitor.

-Water use and food safety! UNH Extension Food Safety State Specialist, Wendy Johnecheck, recently published a blog about Water Use on Produce Farms: A Focus on Food Safety. This is a great refresher and/or resource for requirements and recordkeeping related to FSMA. 

-New pesticide safety resources! UNH Extension Pesticide Safety Education Field Specialist, Rachel Maccini, has recently shared a few blog posts that may be helpful. The links and more information can be found below.

• Safe and Responsible Pesticide Disposal: What to Do with Unused Products

• Why Checking Pesticide Registration in New Hampshire Matters

• Pesticide Labels: I Need a New One

• Introducing Denyce Gagne, new Enforcement Program Manager for Pesticide Control

Rachel also wrote a new article on pesticide efficacy and drought conditions which can be found here. 

The EPA released a new app to help with pesticide label mitigations. More information can be found here.

-Soil pH and nutrient management! UNH Extension Soil Heath State Specialist, Renuka Mathur, put together some information on soil pH and how that impacts nutrient availability. See the Veg IPM Report from 8.15.25 for more information. 

Upcoming events: 

• 2025 North Country Farm & Homestead Conference
  October 15, 2025 | 9:00 a.m. - 3:00 p.m.
  516 Main Street, Lancaster Fair Grounds, Lancaster, NH
  
  Join us for a day of learning, hands-on demonstrations, and community at the North Country Farm & Homestead Conference! Whether you're a homesteader, small-scale farmer, or aspiring grower, this event offers a mix of concurrent sessions and live demonstrations designed to help you build skills, improve your land, and strengthen your operation. From soil health and cover cropping to backyard livestock, beekeeping, and variety trials, you'll gain practical, real-world knowledge tailored to small-scale and diversified farming. Enjoy hands-on activities like chainsaw maintenance, tractor safety, shiitake log inoculation, alongside insightful discussions on food preservation. With opportunities to network with experts, explore the trade show, and share experiences with fellow growers! Cost: $30/person. Registration closes: October 7, 2025. Register and find more information here!

• High Tunnel Production Conference: Enhance Your Tunnel Vision
  December 10, 2025 | 9:00 a.m. - December 11, 2025 | 4:00 p.m.
  Fireside Inn and Suites, 25 Airport Road, West Lebanon, NH 
  
  Calling all high tunnel growers! Whether you are a new or experienced high tunnel grower, plan to join UMaine, UNH, and UVM for this two-day event. Come learn from experts and other farmers, talk with vendors, and see their products at the trade show. This conference will offer useful information for high tunnel growers and agricultural service providers of all experience levels and all crops. Cost is $120 for both days. * Registration fee includes the farm tour, all educational sessions, admission to the trade show, and lunch on Day 2. Additional people from the same farm are just $90 each. Registration deadline is December 3. Find more information about the program and register here!

Reminder--The University of New Hampshire Plant Diagnostic Lab has temporarily suspended its services for the remainder of 2025. In the meantime, please refer to Extension's Plant Diagnostics webpage for a list of labs who have agreed to provide diagnostic services in the interim. Please note that soil analysis, insect identification, and tick testing services remain fully operational. We apologize for any disruptions caused by the temporary closure of the Plant Diagnostic Lab. We will provide updates regarding a reopening plan as it is finalized. 

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010. 

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program!  

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture.  

Hello vegetable IPM folks!

I hope everyone received some much-needed rain this week! Here a couple of drought resources: 

• Guide to Drought Management for NH Growers
• US Drought Monitor

We caught 1 European corn borer moth this week in a corn earworm trap. Our scout has observed little to no ECB damage in the field. Click HERE for more information on ECB management. 

Corn earworm catches have increased, with one location on a 4-day spray schedule and many others on a 5–6-day schedule. If you have silking corn, be sure to scout for CEW and prepare for management. Our trap threshold/spray schedule table can be found in the fact sheet linked below, along with those for ECB and FAW. CEW eggs hatch in 2-5 days depending on temperature and newly hatched larvae move down the silk into the ears quickly. Insecticide control of CEW requires good protective coverage of the ear zone so that when the eggs hatch, the young larvae will immediately contact a lethal dose of insecticide.

A note on corn earworm insecticide resistance: Rotate chemical classes to delay resistance development and help mitigate pyrethroid (Group 3) resistance that may be occurring in the southern US. It’s best to avoid spraying pyrethroids more than twice in a row. New England faces unique challenges in managing insecticide resistance for CEW. The moths are migrating from the southern US, where they were likely already exposed to pesticides and we get new populations every year with varying degrees of resistance. We are also experiencing warmer temperatures and the potential for more pests overwintering in NH that have not historically overwintered here. We also have limited options for insecticide modes of action, some of which may be cost-prohibitive. Continue monitoring moths and insecticide efficacy in controlling CEW. Please let us know if you are no longer seeing control with products that have controlled CEW in the past.

Fall armyworm numbers have dropped by more than half compared to last week. A handful of locations are still over threshold for silking corn and pressure varies by location and number of traps. Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement.  If you have corn between the whorl and silk stage, the threshold is 30% of sample with injury from FAW, and for silking corn, the threshold is 15% injury or 3+ moths/week. You may need to control FAW separately if you have longer spray intervals for CEW. 

Our scout observed 0-25% damage to sweet corn this week from insects depending on location, averaging 7.5% damage across scouted fields. Field scouting should begin once moths are captured at your farm or in your area.  Select at least 5 sites across the planting, all of the same variety and planting date, but in different parts of the field. Avoid sampling at the edge of the field (this may bias your sample since the pests may move in from adjacent crops). For a representative sample, follow a rough X or W pattern across the planting. At each site, examine 20 plants, and look at the whorl area for the tiny “shot holes” that show European corn borers are in that stalk. Often there is a tiny bit of light, powdery frass adjacent to the small holes. If present, mark as infested. FAW moths migrate from the south each year, usually arriving in late July or August. The larvae are voracious feeders and chew large, ragged holes in leaves, leaving behind coarse, messy droppings. FAW prefers the youngest stage corn that is available. If no young corn is available, they attack silks, husks and ears, leaving the same large, ragged holes and messy droppings. As you move across the planting, keep track of two things: 1) how many plants are infested (either FAW or ECB); and 2) the total number of stalks you’ve counted. Stop at 100. Threshold information for the sweet corn caterpillars can be found here. 

Western bean cutworm captures have dropped again from last week, but moths are still present. We generally see this pest increase quickly, hitting its peak in late July, and then decreasing rapidly in early August. This summer’s heat and dry weather may be affecting normal patterns and the slower decline in moths. We do not have a threshold established for this pest in NH. Control measures for other sweet corn caterpillars should control WBC. 

The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town. 

Table 1. Sweet corn pest weekly summary, 8/16-8/22/2025. 

Squash vine borer numbers remain low and like last week, though no locations are over threshold. The first generation is ending and we will keep trapping to determine if there will be a 2^nd generation like we saw in 2024. Larvae of 2^nd generation SVB bore directly into fruit. Our UNH Extension fact sheet is a great resource for this pest. 

Table 2. Squash vine borer weekly summary, 8/16-8/22/2025.  

Spotted wing drosophila numbers continue to increase. If you have susceptible ripening fruit, monitor for SWD and apply management as needed. More information on monitoring for SWD can be found here. Frequent harvesting and placing harvested berries in the fridge can help slow SWD development within the fruit. I also want to share this resource from Cornell on SWD management. It includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 3 below.The control traps are located in unmanaged areas surrounding fields and may have more SWD than reported. 

Table 3. Male SWD captures by crop, 8/18-8/22/2025.  

Brown marmorated stink bug captures have increased since last week. We generally see higher numbers in dry weather and later in the season. Both nymphs and adults can damage crops. Anna Wallingford recorded a podcast on BMSB that can be found here. You can also read through the transcript rather than listen if that is preferred. In NH, BMSB is more of a nuisance pest but can cause damage to agricultural crops, including tomatoes and tree fruit. Captures by location are shown in Table 4 below. 

Table 4. BMSB weekly summary, 8/18-8/22/25. 

Miscellaneous pest information: 

• Melon aphids have been an issue on a couple of farms this year. It’s not surprising that we are seeing melon aphids this year since outbreaks are more common in hot, dry weather. When I worked with melons on the west coast, melon aphids were worse later in the season and usually found on melons, though I have also observed severe infestations on pumpkin fruit too. Melon aphids can attack cucurbits, asparagus, pepper, eggplant, okra. They also have many weed hosts. For cucurbits, they are usually a more serious pest issue on cucumber, muskmelon, and watermelon than squash or pumpkins. Melon aphids overwinter on woody plants or high tunnels. They colonize plants in early summer and have multiple generations per year. They are variable in color, ranging from light green to yellow to a very dark green, almost black. The cornicles at the tip of the abdomen are always black, which is a key diagnostic characteristic to differentiate from other aphids. You can find melon aphid colonies on the undersides of leaves where the aphids are feeding. Damage includes yellowing, puckering, leaf curling/distortion, leaf death and honeydew/sooty mold. They can also transmit various cucurbit viruses. Reflective mulch repels aphids by disrupting their ability to find host plants and row covers can help prevent early infestation and virus transmission if transplants are clean and row cover is placed immediately after planting. There are also varietal differences in how susceptible cucurbits are to melon aphids. If feasible, it may be helpful to remove severely infested plants and destroy them or bury them to prevent population build-ups in the field. Begin scouting for melon aphids in mid-June and if treated with an insecticide, good coverage of leaf undersides is needed so the aphids come into direct contact with insecticides. It’s best to use selective products to protect aphid natural enemies, which can be effective in managing smaller populations. More information can be found in the New England Vegetable Management Guide and this article from University of Maryland which also has photos of melon aphid damage. 

Photo credit: Jim Baker, North Carolina State University, Bugwood.org

• Squash bugs are the primary vectors of cucurbit yellow vine disease (see Disease of the Week below). Summer squash, zucchini, pumpkins, and Cucurbita maxima crops are more susceptible to squash bug feeding damage. Resistant crops include watermelon, cucumber, cantaloupe, and butternut (also relatively resistant to squash vine borer). Row covers can help exclude squash bugs but need to be removed for pollination. Eggs and early nymphs are the easiest stages to control. To reduce risks to bees, treat plants late in the day when flowers are closed.
• Cucumber beetles continue to be found in high numbers on many farms. Cuke beetles transmit bacterial wilt, so try to control them as best as you can, though it gets much more difficult once the plants are flowering and have large canopies.
• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports

Disease of the Week: 

While we have already covered bacterial wilt of cucumbers back in week 7/14, this week, let’s discuss another bacterial disease whose symptoms look similar to bacterial wilt – Cucurbit Yellow Vine Disease (also known as Yellow Vine Decline). This disease is caused by the bacteria Serratia ureilytica and is relatively new to the Northeastern U.S. Symptoms start off as wilting of the plants (similar to both bacterial wilt and drought symptoms) with interveinal yellowing on the leaves. As the disease progresses, the entire leaf and then vine yellow and if the stem is cut, the vascular tissue appears to be honey-brown color – these are diagnostic symptoms of this disease. Cucurbit yellow vine disease can lead to a total collapse of plants. 

The disease is transmitted by squash bugs. The bacteria can overwinter in the adult squash bug and early infections occur when these adults feed on healthy plants. Squash bugs will also transmit bacteria from infected plants to healthy plants as they feed. It can also be transmitted through striped and spotted cucumber beetles (similar to bacterial wilt). 

Current management strategies focus on controlling the squash bug vector. Once a plant is infected with cucurbit yellow vine disease, it cannot be cured and must be removed and destroyed. 

Cucurbit Yellow Vine Disease with yellowing of the entire plant and plant collapse. (B) Bacterial Wilt with scorching of margins and plant collapse. 
Photo credit: Cornell Vegetables Resources for Commercial Growers 
https://www.vegetables.cornell.edu/pest-management/disease-factsheets/cucurbit-yellow-vine-disease/.

Other information of note: 

-New blog on water use and food safety! UNH Extension Food Safety State Specialist, Wendy Johnecheck, recently published a blog about Water Use on Produce Farms: A Focus on Food Safety. This is a great refresher and/or resource for requirements and recordkeeping related to FSMA. 

-New pesticide safety resources! UNH Extension Pesticide Safety Education Field Specialist, Rachel Maccini, has recently shared a few blog posts that may be helpful. The links and more information can be found below.

• Safe and Responsible Pesticide Disposal: What to Do with Unused Products
• Why Checking Pesticide Registration in New Hampshire Matters
• Pesticide Labels: I Need a New One
• Introducing Denyce Gagne, new Enforcement Program Manager for Pesticide Control

Rachel also wrote a new article on pesticide efficacy and drought conditions which can be found here. 

-Soil pH and nutrient management! UNH Extension Soil Heath State Specialist, Renuka Mathur, put together some information on soil pH and how that impacts nutrient availability. See the Veg IPM Report from 8.15.25 for more information. 

Upcoming events: 

NEXT WEEK! Two twilight meetings for Beginner Farmers!

• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30 p.m. -7:30 p.m. | August 25, 2025
  Location: Pete's Stand, 51 Main St., Walpole, NH 
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-growers-walpole-nh
• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30 p.m. -7:30 p.m. | August 28, 2025
  Location: Slopeside Farm, 148 Stebbins Hill, Lancaster, NH
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-beginning-farmers

Effective pest management starts with knowing what’s happening in your field. These hands-on workshops focus on the critical role of scouting in Integrated Pest Management (IPM), specifically on vegetable crops. The Slopeside event will focus on brassicas and alliums. Participants will learn how to detect pest problems early, differentiate pest damage from disease or environmental stress, and practice pest ID. The evening will include interactive discussions, live scouting demonstrations, and group exercises to build your skills in the field. These events are offered at no cost and open to the public. Contact Caroline Beaton, caroline.beaton@unh.edu, with any questions. For persons with disabilities requiring special accommodations, please contact Caroline Beaton prior to the event. Given ample time, we will make any reasonable effort to make accommodations. This work is supported by the Beginner Farmer Rancher Development Program, project award no.2024-49400-43622, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.

Reminder--The University of New Hampshire Plant Diagnostic Lab has temporarily suspended its services for the remainder of 2025. In the meantime, please refer to Extension's Plant Diagnostics webpage for a list of labs who have agreed to provide diagnostic services in the interim. Please note that soil analysis, insect identification, and tick testing services remain fully operational. We apologize for any disruptions caused by the temporary closure of the Plant Diagnostic Lab. We will provide updates regarding a reopening plan as it is finalized.  

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010. 

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program!  

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture.  

Hello vegetable IPM folks!   

We have one update before we get into pest information.

The University of New Hampshire Plant Diagnostic Lab has temporarily suspended its services for the remainder of 2025. In the meantime, please refer to Extension's Plant Diagnostics webpage for a list of labs who have agreed to provide diagnostic services in the interim. Please note that soil analysis, insect identification, and tick testing services remain fully operational. We apologize for any disruptions caused by the temporary closure of the Plant Diagnostic Lab. We will provide updates regarding a reopening plan as it is finalized.

We caught 2 European corn borers this week in one location. Click HERE for more information on ECB management. 

Corn earworm catches are a little lower than last week, with a couple of locations on a 4-day spray schedule. We have not had many storms to bring these moths north. If you have silking corn, be sure to scout for CEW and prepare for management. Our trap threshold/spray schedule table can be found in the fact sheet linked below, along with those for ECB and FAW.  CEW eggs hatch in 2-5 days depending on temperature and newly hatched larvae move down the silk into the ears quickly. Insecticide control of CEW requires good protective coverage of the ear zone so that when the eggs hatch, the young larvae will immediately contact a lethal dose of insecticide. 

Fall armyworm numbers are slightly lower than last week but still total over 100 moths. Many locations are over threshold for silking corn and pressure varies by location and number of traps. Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement.  If you have corn between the whorl and silk stage, the threshold is 30% of sample with injury from FAW, and for silking corn, the threshold is 15% injury or 3+ moths/week. 

Our scout observed 4-35% damage to sweet corn this week from fall armyworm depending on location, averaging 6.7% damage across scouted fields. Field scouting should begin once moths are captured at your farm or in your area.  Select at least 5 sites across the planting, all of the same variety and planting date, but in different parts of the field. Avoid sampling at the edge of the field (this may bias your sample since the pests may move in from adjacent crops). For a representative sample, follow a rough X or W pattern across the planting. At each site, examine 20 plants, and look at the whorl area for the tiny “shot holes” that show European corn borers are in that stalk. Often there is a tiny bit of light, powdery frass adjacent to the small holes. If present, mark as infested. FAW moths migrate from the south each year, usually arriving in late July or August. The larvae are voracious feeders. Larvae chew large, ragged holes in leaves, and leave lots of coarse, messy droppings. FAW prefers the youngest stage corn that is available. If no young corn is available, they attack silks, husks and ears, leaving the same large, ragged holes and messy droppings. As you move across the planting, keep track of two things: 1) how many plants are infested (either FAW or ECB); and 2) the total number of stalks you’ve counted. Stop at 100. Threshold information for the sweet corn caterpillars can be found here. 

Western bean cutworm captures have also dropped a little, but moths are still present. We generally see this pest increase quickly, hitting its peak in late July, and then decreasing rapidly in early August. This summer’s heat and dry weather may be affecting normal patterns. It will be interesting to see if moth numbers decrease or continue to increase in the coming weeks. We do not have a threshold established for this pest in NH. Control measures for other sweet corn caterpillars should control WBC. 

The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town. 

Table 1. Sweet corn pest weekly summary, 8/9-8/15/2025. 

Squash vine borer numbers are much lower than last week with only one location over threshold for bush-type cucurbits (5/week). The first generation is ending and we will keep trapping to determine if there will be a 2^nd generation like we saw in 2024. Larvae of 2^nd generation SVB bore directly into fruit. Our UNH Extension fact sheet is a great resource for this pest. 

Table 2. Squash vine borer weekly summary, 8/9-8/15/2025.  

Spotted wing drosophila numbers are similar to last week with high numbers in raspberries. If you have susceptible ripening fruit, monitor for SWD and apply management as needed. More information on monitoring for SWD can be found here. Frequent harvesting and placing berries in the fridge can help slow SWD development within the fruit. I also want to share this resource from Cornell on SWD management. It includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 3 below.The control traps are located in unmanaged areas surrounding fields. 

Table 3. Male SWD captures by crop, 8/11-8/15/2025.  

Brown marmorated stink bug captures have started increasing since last week when we only caught 3 adults and 1 nymph. We have 10 sentinel traps for BMSB in southern New Hampshire. We generally see higher numbers in dry weather and later in the season. Both nymphs and adults can damage crops. Anna Wallingford recorded a podcast on BMSB that can be found here. You can also read through the transcript rather than listen if that is preferred. In NH, BMSB is more of a nuisance pest but can cause damage to agricultural crops, including tomatoes and tree fruit. Captures by location are shown in Table 4 below. 

Table 4. BMSB weekly summary, 8/11-8/15/25. 

Miscellaneous pest information: 

• Two-spotted spider mites (TSSM) have been reported in strawberry but are also the most common mite species on many vegetable crops including beans, tomato, eggplant, and cucurbits. The hot, dry weather and dusty conditions over the past few weeks are perfect for spider mite populations to build quickly. TSSM have piercing-sucking mouthparts and can be found on the underside of leaves. A 10-15X hand lens is best to spot them moving around the underside of leaves, along with the presence of fine webbing, which can differentiate TSSM from other piercing-sucking pests, like leafhoppers. White speckling or stippling on upper surfaces of leaves, bronzing/dull/dried-out appearance of leaves, leaf distortion, loss of plant vigor, and even stunting can all be symptoms of TSSM feeding. Overhead irrigation or rain can help reduce populations. Avoid planting in weedy fields if possible and avoid over-fertilizing. Avoid early-season, broad-spectrum insecticide applications for other pests, this may flare mite populations since beneficial insects can keep mite populations in check when populations are lower. When spraying, coverage of the underside of leaves is important. Rotate IRAC groups to prevent or delay resistance. More information on TSSM management can be found in multiple crop sections of the New England Vegetable Management Guide, but Eggplant is the most detailed since TSSM is a key pest of eggplant. Management and threshold information for strawberries can be found in the Small Fruit Management Guide.  
• Corn leaf aphids have been observed on a couple of farms in Merrimack County. These aphids are bluish/green or black with black legs. Rainfall or irrigation during the silk stage can reduce or eliminate aphid populations, but we have had limited rainfall this summer. It's best to use materials that conserve natural predators, when possible, though they are unlikely to keep heavy populations under control. Monitoring for aphids is best done during the whorl or pre-tassel stage in July and August, and early corn is less likely to get severe CLA infestations.  Sprays may be warranted when 25% of pre-tassel plants have severe aphid pressure or 50% have aphids. Generally, sprays applied before 50% of tassels emerge are more effective than later sprays. More information can be found in the NE Vegetable Mgmt. Guide.
• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports

Disease of the Week: 

Black rot of Brassica, caused by the bacteria Xanthomonas campestris pv. campestris, is considered the most devastating disease of brassica globally, affecting crops such as cabbage, broccoli, cauliflower, canola, and rapeseed. The infection results in vascular decay that has the potential to devastate crop yield and quality. Black rot can appear at any point during the growth of the plant, but seedling infection is of significant importance as early detection may aid growers in terminating the crop promptly and reduce spread. Initial symptoms begin as yellowing at leaf edges in a characteristic V-shaped lesion. As symptoms progress, plants can develop blackened vascular tissue and head rot. Disease development is favored by warm temperatures with high humidity weather.

Cultural practices that can control black rot include planting varieties that have resistance, although these options are limited. Most importantly, black rot is a bacterial disease that spreads through water so managing water is key to managing this disease, thus using drip irrigation is key to preventing black rot on your farm. Always buy clean seed and screen transplants for symptoms. Avoid planting brassica crops in the same location or in fields with poor drainage. Other cultural controls include providing good air movement around plants and reducing leaf wetness through proper spacing. 

Since black rot is a bacterial disease, fungicides are ineffective. Copper products are most commonly used for control but can lead to resistance. The only other products available are biopesticides which can be used in combination or in rotation with copper. Actigard, Leap ES, and Howler are all biopesticide options. Ultimately it may be more cost effective to terminate the crop completely, thus prevention is key. 

Cabbage black rot symptoms. Photo credit: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Cabbage black rot symptoms. Photo credit: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Other information of note: 

-New blog on water use and food safety! UNH Extension Food Safety State Specialist, Wendy Johnecheck, recently published a blog about Water Use on Produce Farms: A Focus on Food Safety. This is a great refresher and/or resource for requirements and recordkeeping related to FSMA. 

-New pesticide safety resources! UNH Extension Pesticide Safety Education Field Specialist, Rachel Maccini, has recently shared a few blog posts that may be helpful. The links and more information can be found below.

• Safe and Responsible Pesticide Disposal: What to Do with Unused Products
• Why Checking Pesticide Registration in New Hampshire Matters
• Pesticide Labels: I Need a New One
• Introducing Denyce Gagne, new Enforcement Program Manager for Pesticide Control

Rachel also wrote a new article on pesticide efficacy and drought conditions which can be found here. 

-Soil pH and nutrient management! UNH Extension Soil Heath State Specialist, Renuka Mathur, put together some information on soil pH and how that impacts nutrient availability. 

Soil pH is a key factor in determining plant health because it directly affects nutrient availability. If the pH falls outside a plant's optimal range, growth can be stunted and yields reduced. While most cultivated agronomic and horticultural plants thrive at a pH between 6.0 and 6.8, some species, like blueberries and rhododendrons, prefer more acidic conditions (pH 4.5-5.5).

 Soil pH influences the solubility of nutrients in soil water. The more soluble a nutrient is, the more easily it can be absorbed by plant roots. When the pH drops below 6.0, nutrients such as phosphorus, nitrogen, potassium, calcium and magnesium become less available. Additionally, acidic soils can release elements like aluminum, manganese, and iron in amounts that are toxic to plant roots. Similarly, a high pH (above 7.3) can make essential micronutrients like iron, copper, and zinc inaccessible.

The pH of the soil also impacts biological activity and microbial activity. Microbes are essential for making nutrients like nitrogen, phosphorus, and sulfur available to plants. In acidic soils with a pH below 5.5, microbial activity slows, reducing the breakdown of organic matter. A pH between 6 and 7 is ideal for maximizing both bacterial and fungal activity. To adjust soil pH, limestone is commonly used to raise it, while sulfur is used to lower it. The amount needed depends on the soil's buffering capacity, with soils containing more clay and organic matter requiring more material to change the pH.

Lime (to raise pH):

• Best: Fall before spring vegetables or new plantings. If missed in fall, early spring if needed. Incorporate to 4–8″ depth for faster reaction.
  • Brassicas in clubroot rotations: Finish any hydrated/reactive lime push ≥6 weeks pre-transplant.
  • Orchards/vineyards: Apply pre-plant (months ahead) to correct the whole profile. In established orchard, surface applications well in advance as surface applications react very slowly. 

Elemental sulfur (to lower pH):

• Best: Pre-plant going into the warm season (spring to early summer) for quickest microbial oxidation; split large rates and retest after ~6 months.
  • Blueberries: Apply 3–4 months pre-plant; for maintenance, make smaller spring adjustments and monitor annually.
  • Orchards with high pH: Use sulfur to move back toward ~6.0–6.5, timed to warm, moist conditions.

Upcoming events: 

• Next week! Registration deadline TODAY (8/15)! Tree Fruit Twilight Meeting @ Brookdale Farm
  5:30 p.m. - 7:30 p.m., August 20, 2025
  Location: Brookdale Farm, 41 Broad St., Hollis, NH
  
  More information here. Join us for this in-person tree fruit twilight meeting where topics will include a field tour including equipment and technology demos. These demos will highlight equipment for mowing, sucker removing, pruning, and picking and technology such as sap flow sensors, a NEWA weather station update and model utilization. There will also be a cookout so please note that you do need to register if you plan to stay for the cookout. We need your registration by Friday, August 15th, so we can be sure there is plenty of food for all. Contact Samantha Pitarys, samanthabf08@gmail.com, or call (603) 552-8062 for the registration form.

Two twilight meetings for Beginner Farmers!

• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30 p.m. - 7:30 p.m., August 25, 2025
  Location: Pete's Stand, 51 Main St., Walpole, NH 
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-growers-walpole-nh
• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30 p.m. - 7:30 p.m., August 28, 2025
  Location: Slopeside Farm, 148 Stebbins Hill, Lancaster, NH
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-beginning-farmers
  
  Effective pest management starts with knowing what’s happening in your field. These hands-on workshops focus on the critical role of scouting in Integrated Pest Management (IPM), specifically on vegetable crops. The Slopeside event will focus on brassicas and alliums. Participants will learn how to detect pest problems early, differentiate pest damage from disease or environmental stress, and practice pest ID. The evening will include interactive discussions, live scouting demonstrations, and group exercises to build your skills in the field. These events are offered at no cost and open to the public. Contact Caroline Beaton, caroline.beaton@unh.edu, with any questions. For persons with disabilities requiring special accommodations, please contact Caroline Beaton prior to the event. Given ample time, we will make any reasonable effort to make accommodations. This work is supported by the Beginner Farmer Rancher Development Program, project award no.2024-49400-43622, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010. 

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program!  

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture.  

Hello vegetable IPM folks!    

We caught 13 European corn borer this week but only in 2 locations. These captures may indicate 2^nd generation activity. Click HERE for more information on ECB management. 

Corn earworm catches remain similar to last week, with specific locations experiencing high pressure. If you have silking corn, be sure to scout for CEW and prepare for management. Our trap threshold/spray schedule table can be found in the fact sheet linked below, along with those for ECB and FAW.  CEW eggs hatch in 2-5 days depending on temperature and newly hatched larvae move down the silk into the ears quickly. Insecticide control of CEW requires good protective coverage of the ear zone so that when the eggs hatch, the young larvae will immediately contact a lethal dose of insecticide.

Fall armyworm numbers continue to increase. This week, FAW damage has been observed in almost every corn growth stage. Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement.  If you have corn between the whorl and silk stage, the threshold is 30% of sample with injury from FAW, and for silking corn, the threshold is 15% injury or 3+ moths/week.

Our scout observed 1-77% damage to sweet corn this week from fall armyworm depending on location. Heavy bird damage was also observed. Field scouting should begin once moths are captured at your farm or in your area.  Select at least 5 sites across the planting, all of the same variety and planting date. Avoid sampling at the edge of the field (this may bias your sample since the pests may move in from adjacent crops). For a representative sample, follow a rough X or W pattern across the planting. At each site, examine 20 plants, and look at the whorl area for the tiny “shot holes” that show European corn borers are in that stalk. Often there is a tiny bit of light, powdery frass adjacent to the small holes. If present, mark as infested. FAW moths migrate from the south each year, usually arriving in late July or August. The larvae are voracious feeders. Larvae chew large, ragged holes in leaves, and leave lots of coarse, messy droppings. FAW prefer the youngest stage corn that is available. If no young corn is available, they attack silks, husks and ears, leaving the same large, ragged holes and messy droppings. As you move across the planting, keep track of two things: 1) how many plants are infested (either FAW or ECB); and 2) the total number of stalks you’ve counted. Stop at 100. Threshold information for the sweet corn caterpillars can be found here.

Western bean cutworm captures have increased. We generally see this pest increase quickly, hitting its peak in late July, and then decreasing rapidly in early August. This summer’s heat may be affecting normal patterns. It will be interesting to see if moth numbers decrease or continue to increase in coming weeks.

The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town.  

Table 1. Sweet corn pest weekly summary, 8/2-8/8/2025. 

Squash vine borer numbers are similar to last week indicating a slow end of the 1^st generation. Some locations are above threshold for bush-type and vining-type cucurbits (Table 2). For bush-type summer squash and pumpkins (including giant pumpkins), the recommended threshold is 5 SVB moths per trap per week. For vining type squash or pumpkins, we suggest a threshold of 12 moths per trap per week. Vine-type cucurbits can root or tiller in at each node along the vine which allows the plant to take up water and nutrients from more than just the main stem. SVB tends to bore into the main stem of cucurbit plants, creating a higher risk for bush type plants.  Butternut and cucumber have some resistance to SVB. Target the base of the stem to treat newly hatched larvae before they bore into the stem. This pest is also becoming more prevalent in northern New Hampshire, where, historically, it was not a major issue. Our UNH Extension fact sheet is a great resource for this pest.

Table 2. Squash vine borer weekly summary, 8/2-8/8/2025.  

Spotted wing drosophila numbers have more than doubled from last week. If you have susceptible ripening fruit, monitor for SWD and apply management as needed. More information on monitoring for SWD can be found here. Frequent harvesting and placing berries in the fridge can help slow SWD development within the fruit. I also want to share this resource from Cornell on SWD management. It includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 3 below. The control traps are located in unmanaged areas surrounding fields.

Table 3. Male SWD captures by crop, 8/4-8/8/2025.  

Miscellaneous pest information: 

• Cabbage root maggot affects all brassicas but is especially damaging to cabbage, broccoli, Chinese cabbage, radish, turnips, and rutabaga. The first adult flight in April–May targets spring brassicas, while the third flight (mid-August–September) damages fall root crops. Flies overwinter as pupae near the roots of brassicas and weeds. We are getting close to peak third flight early next week due to the warmer temperatures we have seen this summer. There is a degree day model for cabbage maggot on NEWA (https://newa.cornell.edu/cabbage-maggot). There are 2–3 generations per year in New England. 1^st and 2^nd generation are usually more damaging than the 3^rd generation.
  • Adults emerge around 288 GDD (base 40°F), with peak flight at ~450 GDD.
  • Eggs are small, white, and bullet-shaped, laid near plant stems in the top 1–3" of soil, especially in moist, rich soils.
    • Eggs are killed by soil temperatures over 95°F for several consecutive days, especially in dry soils—common in late May/early June. 
  • Maggots are white with black mouth hooks and feed on roots.
    • Root damage can cause wilting, yellowing or purpling, stunting, delays, or plant death. 
  • Pupae are brown and oval, also found near roots.
    Cultural controls include incorporating and disking crop residues after harvest to expose and kill pupae, rotating spring crops to fields without a history of brassicas, avoiding spring manure/compost applications and wet field areas, row cover on rotated fields to prevent adult flies from laying eggs (install covers at seeding/transplanting), delaying spring planting to avoid peak flights and allowing soils to warm. Row covers will not be effective on non-rotated plantings because the adult flies will emerge from the soil under the row cover. Cabbage maggots can be monitored with yellow sticky cards and using growing degree models to detect and predict adult flights. Once adults are active, scout trays and field plants for eggs. One egg per plant can indicate a damaging population. Check transplant trays before field planting; treat if eggs are found using labeled drenches or insecticide in transplant water. Post-plant chemical options are limited, so focus on early detection and prevention. Resistance to organophosphates (Group 1B) has been reported—rotate chemical classes when using insecticides. More information can be found in the New England Vegetable Management Guide.
• Onion thrips may now be moving from onion fields to cabbage. They feed on inner leaves of the head which are difficult to target with sprays. Damage may be seen on leafy brassicas too, like broccoli, kale and collards, especially if planted near a maturing onion crop. Thrips feeding causes rough, brownish scars to form on the underside of leaves and can produce scars and discolored layers within cabbage heads. Damage is most severe in hot, dry weather which has been frequent this year. Plant cabbage or fall brassicas away from alliums or field crops (alfalfa, clover, wheat, oats) if possible, since these crops can harbor thrips. Scout young plants for thrips feeding injury. Information on chemical management can be found in the NE Vegetable Management Guide.

Onion thrips on cabbage. Photo credit: Whitney Cranshaw, Colorado State University, Bugwood.org

• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports

Disease of the Week:

Basil Downy Mildew – it was reported in eastern NY last week, and UMass sent out an alert yesterday that it was found on their susceptible controls in their basil variety trial in Deerfield, MA. Basil downy mildew is caused by the water mold, Peronospora belbahrii, which is a different species than the water mold that causes cucurbit downy mildew. However, a lot of the symptoms are similar: infections start on lower leaves and appear as pale-yellow areas on the upper leave with velvety, grey fuzz on the underside of the leaf. Basil downy mildew can spread rapidly so scouting is key to prevent complete yield losses. While basil downy mildew can be transferred by seed or transplants, the spores will also move on air currents, thus why reports from our neighboring states are so important. Disease development is favored by warm temperatures with humid conditions but can tolerate cool weather.

The most effective tool for preventing basil downy mildew is using resistant cultivars. UMass reported on several varieties that performed well in recent years including: Prospera Premium and Prospera Active series, Evi, Amazel, Pesto Besto, Giulietta, Devotion, Passion, Obsession, and Thunderstruck. Genovese basil and other sweet varieties are the most susceptible type of basil. Other cultural controls are monitoring all seedling and transplants prior to planting, destroying any infected plant. As always, reduce leaf wetness through increased spacing, drip irrigation, and manage humidity if growing in a greenhouse or hoop house.

A group of researchers from several states are trying to better understand existing populations of this pathogen to help drive solutions to the problem. You can help these researchers by reporting occurrences of the disease at https://basil.agpestmonitor.org/ and sending infected leaf samples to the researchers to better understand the existing pathogen populations and help drive solutions towards the downy mildew problem. This problem cannot be solved alone! Contact Liza DeGenring if you observe Basil Downy Mildew symptoms and she will work with you to get the samples to Rutgers.

Fungicide recommendations can be found in the New England Vegetable Management Guide. Additionally, Meg McGrath has a lot of research on the most effective products. To control basil downy mildew effectively with fungicides, it is considered necessary to start before first symptoms and to make applications frequently.

Basil Downy Mildew. Photo credit: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

New pesticide safety resources! UNH Extension Pesticide Safety Education Field Specialist, Rachel Maccini, has recently shared a few blog posts that may be helpful. These links and more information can be found below.

• Safe and Responsible Pesticide Disposal: What to Do with Unused Products
• Why Checking Pesticide Registration in New Hampshire Matters
• Pesticide Labels: I Need a New One
• Introducing Denyce Gagne, new Enforcement Program Manager for Pesticide Control

Rachel also wrote a new article on pesticide efficacy and drought conditions which can be found here.

Upcoming events:

Tree Fruit Twilight Meeting @ Brookdale Farm
5:30-7:30pm, August 20, 2025
Location: Brookdale Farm, 41 Broad St., Hollis, NH
More information here.

Join us for this in-person tree fruit twilight meeting where topics will include a field tour including equipment and technology demos. These demos will highlight equipment for mowing, sucker removing, pruning, and picking and technology such as sap flow sensors, a NEWA weather station update and model utilization. There will also be a cookout so please note that you do need to register if you plan to stay for the cookout. We need your registration by Friday, August 15th, so we can be sure there is plenty of food for all. Contact Samantha Pitarys, samanthabf08@gmail.com, or call (603) 552-8062 for the registration form.

Two twilight meetings for Beginner Farmers!

• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30-7:30pm, August 25, 2025
  Location: Pete's Stand, 51 Main St., Walpole, NH
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-growers-walpole-nh

• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30-7:30pm, August 28, 2025
  Location: Slopeside Farm, 148 Stebbins Hill, Lancaster, NH
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-beginning-farmers

Effective pest management starts with knowing what’s happening in your field. These hands-on workshops focus on the critical role of scouting in Integrated Pest Management (IPM), specifically on vegetable crops. The Slopeside event will focus on brassicas and alliums. Participants will learn how to detect pest problems early, differentiate pest damage from disease or environmental stress, and practice pest ID. The evening will include interactive discussions, live scouting demonstrations, and group exercises to build your skills in the field. These events are offered at no cost and open to the public.

Contact Caroline Beaton, caroline.beaton@unh.edu, with any questions. For persons with disabilities requiring special accommodations, please contact Caroline Beaton prior to the event. Given ample time, we will make any reasonable effort to make accommodations.

This work is supported by the Beginner Farmer Rancher Development Program, project award no.2024-49400-43622, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010.

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program!

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture. 

Hello vegetable IPM folks!

We caught 1 European corn borer this week. We can expect the 2^nd generation of ECB moths to begin flying anytime based on degree day accumulation. Click HERE for more information on ECB management. 

Corn earworm catches area little lower than last week, with weekly averages ranging from 0-16 moths depending on location. If you have silking corn, be sure to scout for CEW and prepare for management. Our trap threshold/spray schedule table can be found in the fact sheet linked below, along with those for ECB and FAW.

Fall armyworm numbers have tripled this week compared to last week. This week, FAW damage has been observed in young whorl-stage corn (see photos below). Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement.  If you have corn between the whorl and silk stage, the threshold is 30% of sample with injury from FAW, and for silking corn, the threshold is 15% injury or 3+ moths/week.

Fall armyworm feeding damage on young corn. Photo credit:  Amber  Vinchesi-Vahl

Young FAW larva and damage. Photo credit: Amber Vinchesi-Vahl

Our scout observed 0-13% damage to sweet corn this week. Field scouting should begin once moths are captured at your farm or in your area.  Select at least 5 sites across the planting, all of the same variety and planting date. Avoid sampling at the edge of the field (this may bias your sample since the pests may move in from adjacent crops). For a representative sample, follow a rough X or W pattern across the planting. At each site, examine 20 plants, and look at the whorl area for the tiny “shot holes” that show European corn borers are in that stalk. Often there is a tiny bit of light, powdery frass adjacent to the small holes. If present, mark as infested. FAW moths migrate from the south each year, usually arriving in late July or August. The larvae are voracious feeders. Larvae chew large, ragged holes in leaves, and leave lots of coarse, messy droppings. FAW prefer the youngest stage corn that is available. If no young corn is available, they attack silks, husks and ears, leaving the same large, ragged holes and messy droppings. As you move across the planting, keep track of two things: 1) how many plants are infested (either FAW or ECB); and 2) the total number of stalks you’ve counted. Stop at 100. Threshold information for the sweet corn caterpillars can be found here.

Western bean cutworm captures have dropped slightly. We generally see this pest increase quickly, hitting its peak in late July, and then decreasing rapidly in early August. No egg masses have been observed.

The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town.  

Table 1. Sweet corn pest weekly summary, 7/26-8/1/2025. 

Squash vine borer captures have dropped indicating the end of the 1^st generation. Some locations are above threshold for bush-type cucurbits (Table 2). For bush-type summer squash and pumpkins (including giant pumpkins), the recommended threshold is 5 SVB moths per trap per week. For vining type squash or pumpkins, we suggest a threshold of 12 moths per trap per week. Vine-type cucurbits can root or tiller in at each node along the vine which allows the plant to take up water and nutrients from more than just the main stem. SVB tends to bore into the main stem of cucurbit plants, creating a higher risk for bush type plants.  Butternut and cucumber have some resistance to SVB. Target the base of the stem to treat newly hatched larvae before they bore into the stem. This pest is also becoming more prevalent in northern New Hampshire, where, historically, it was not a major issue. Our UNH Extension fact sheet is a great resource for this pest.

Table 2. Squash vine borer weekly summary, 7/26-8/1/2025.  

Spotted wing drosophila numbers remain high during peak berry season. If you have susceptible ripening fruit, I recommend monitoring for SWD. More information on monitoring for SWD can be found here. Frequent harvesting and placing berries in the fridge can help slow SWD development within the fruit. I also want to share this resource from Cornell on SWD management. It includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 3 below. The control traps are located in unmanaged areas surrounding fields.

Table 3. Male SWD captures by crop, 7/28-8/1/2025.

We have not caught any brown marmorated stink bugs yet this year.

Miscellaneous pest information: 

• Be on the lookout for basil downy mildew! More information can be found in the NE Veg Mgmt Guide.
• Pepper maggot damage was seen in southern NH. Oviposition scars show up as sunken pinpricks in pepper fruit (see photo below). The scars are especially noticeable on cherry peppers (a preferred host), which can be used as indicator plants in outer rows to time insecticide sprays targeting adult flies. Pepper maggot pressure is variable by location, where some farms never have issues and others deal with it each year. More information can be found in the Pepper section of the New England Vegetable Management Guide. An earlier July issue of the UMass Veg Notes also has more information on pepper maggot if you scroll down.

Pepper maggot oviposition scars on cherry pepper. Photo credit: Amber Vinchesi-Vahl

• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports 

UPDATE! Cucurbit Downy Mildew (CDM) has been confirmed in three New Hampshire counties (Cheshire, Hillsborough and Merrimack) and in Massachusetts (Franklin County). The biology and symptoms can be reviewed in the July 7, 2025 Vegetable IPM report. As a reminder, CDM is caused by the fungal pathogen Pseudoperonospora cubensis and can affect all cucurbit plants BUT most of the outbreaks reported are on cucumbers and melons. Symptoms appear as pale-yellow, angular leaf spots on the upper surface of the leaf and dark purplish-grey fuzzy spores on the underside of the leaf.

Farmers should begin applying fungicides prior to symptoms now that CDM is present in the state. Downy mildew has a high likelihood of fungicide resistance, so many products historically used are no longer effective (Quadris, Revus, Forum, Ridomil). Please rotate FRAC numbers to slow the buildup of resistance in our fields and to maintain good control options. 

To prevent disease before symptoms appear, growers can apply chlorothalonil, mancozeb, or Zampro. Once symptoms appear and you are managing the disease there are two options: tank mix with a protectant (chlorothalonil or mancozeb) and one of these products: Ranman, Presdio, Pervicur. Option 2 is to apply without a protectant and use one of these products: Orondis Opti/Ultra, Omega, Gravel, and Zing!

Orondis Opti/Ultra, Ranman, and Elumin are rated as good efficacy against downy mildew, while Zampro, Tanos, Previcur Flex, Omega, and Ridomil Gold + Bravo were rated as fair efficacy based on the 2025 Southeastern US Vegetable Crop Handbook (page 223). More detailed fungicide information and options for conventional and organic commercial growers can be found in the New England Vegetable Management Guide.

Please reach out to Liza or your local county field specialist if you believe you have CDM in your field or have any questions. 

Upcoming events:

Tree Fruit Twilight Meeting @ Brookdale Farm
5:30-7:30pm, August 20, 2025
Location: Brookdale Farm, 41 Broad St., Hollis, NH
More information here.

Join us for this in-person tree fruit twilight meeting where topics will include a field tour including equipment and technology demos. These demos will highlight equipment for mowing, sucker removing, pruning, and picking and technology such as sap flow sensors, a NEWA weather station update and model utilization. There will also be a cookout so please note that you do need to register if you plan to stay for the cookout. We need your registration by Friday, August 15th, so we can be sure there is plenty of food for all. Contact Samantha Pitarys, samanthabf08@gmail.com, or call (603) 552-8062 for the registration form.

Two twilight meetings for Beginner Farmers!

• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30-7:30pm, August 25, 2025
  Location: Pete's Stand, 51 Main St., Walpole, NH
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-growers-walpole-nh

• Scouting for Success: Practical Pest Monitoring for Beginning Farmers
  5:30-7:30pm, August 28, 2025
  Location: Slopeside Farm, 148 Stebbins Hill, Lancaster, NH
  Register here: https://extension.unh.edu/event/2025/08/scouting-success-practical-pest-monitoring-beginning-farmers

Effective pest management starts with knowing what’s happening in your field. These hands-on workshops focus on the critical role of scouting in Integrated Pest Management (IPM), specifically on vegetable crops. The Slopeside event will focus on brassicas and alliums. Participants will learn how to detect pest problems early, differentiate pest damage from disease or environmental stress, and practice pest ID. The evening will include interactive discussions, live scouting demonstrations, and group exercises to build your skills in the field. These events are offered at no cost and open to the public.

Contact Caroline Beaton, caroline.beaton@unh.edu, with any questions. For persons with disabilities requiring special accommodations, please contact Caroline Beaton prior to the event. Given ample time, we will make any reasonable effort to make accommodations.

This work is supported by the Beginner Farmer Rancher Development Program, project award no.2024-49400-43622, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.

Please sign up for our text service! To sign up: text UNHIPM to (866) 645-7010. 

Check back in each week as the season progresses to see the latest trapping data. Data for additional insect pests will be updated on a weekly basis. Thank you to all the growers who participate in the program!

For any plant disease diagnostics, contact the UNH Extension Plant Diagnostic Lab to submit a sample. 

Contacts: Amber Vinchesi-Vahl, UNH Extension State Specialist, Entomology and IPM, Amber.Vinchesi@unh.edu; Liza DeGenring, UNH Extension Field Specialist, Hillsborough County, Liza.DeGenring@unh.edu 

This program is made possible thought funding provided by the New Hampshire Department of Agriculture, Markets & Food Integrated Pest Management Program. This work is also supported in part by the University of New Hampshire Integrated Pest Management Extension Implementation Plan, project award no. 2024-70006-43535, from the U.S. Department of Agriculture's National Institute of Food and Agriculture.  

Hello vegetable IPM folks!    

We caught 1 European corn borer this week and observed larvae in a couple of locations. We have been seeing larval feeding damage in the field despite the lack of adult captures. We can expect the 2^nd generation of ECB moths to begin flying this week or next based on degree day accumulation. Click HERE for more information on ECB management.

Corn earworm catches are similar to last week (over 70 total), with weekly averages ranging from 0-5 moths depending on location. If you have silking corn, be sure to scout for CEW and prepare for management. Farms are between 5-day and no spray schedules. Our trap threshold/spray schedule table can be found in the fact sheet linked below, along with those for ECB and FAW.

We caught 48 fall armyworm moths this week. Our scout reports old FAW damage that plants have recovered from. Be on the lookout for larval feeding damage which is characterized by large, ragged holes in leaves, and sawdust-like excrement.  If you have corn between the whorl and silk stage, the threshold is 30% of sample with injury from FAW, and for silking corn, the threshold is 15% injury or 3+ moths/week.

I also want to share a recent alert sent out by UNH Extension Field Specialist, Carl Majewski, earlier this week regarding reports of armyworms in hay fields. These are true armyworms, but fall armyworms can cause similar damage, and both species could potentially impact corn fields as well as hay fields.  

Armyworms collected from a farm in the Kearsarge Valley. Photo credit: Anonymous

“Armyworm in Pastures and Hayfields: We’ve received a report of heavy damage from true armyworm damage in hayfields. While this does not necessarily mean there are widespread infestations – armyworm infestations are often patchy – you might want to check on hayfields, especially recently harvested fields with tender second- or third-cut growth.

True armyworm caterpillars come in various shades of green and brown, but they all have orange and white stripes running the length of their body (see photo). While caterpillars have likely been in fields for a while now, they are now in later instars that feed the most heavily. Most feeding takes place at night, so you may not see caterpillars in daylight except in very heavy infestations.

Scout your hayfields and pastures, especially any that seem to be declining after strong regrowth. If armyworms are present at more than three per square foot, you’ll want to take action. There are no insecticides registered for use on grass hayfields, so your best option is to harvest the field as soon as you can – waiting even a couple days for ideal drying conditions will result in extensive damage.

If you have any questions email carl.majewski@unh.edu, or call (603) 352-4550.”

Western bean cutworm captures have more than doubled compared to last week (30 to 67). We generally see this pest increase quickly, hitting its peak in late July, and then decreasing rapidly in early August.

Our scout observed 0-10% damage to sweet corn this week. Field scouting should begin once moths are captured at your farm or in your area. Scouting and threshold information for the sweet corn caterpillars can be found here. The results of our trapping efforts for sweet corn pests are recorded by town in Table 1 below. In some cases, there are multiple traps within a town.

Table 1. Sweet corn pest weekly summary, 7/21-7/25/2025. 

Squash vine borer captures are lower than last week but remain high in certain locations. Many locations are above threshold for bush-type cucurbits and a handful of locations are also above thresholds for vining-type cucurbits (Table 2). For bush-type summer squash and pumpkins (including giant pumpkins), the recommended threshold is 5 SVB moths per trap per week. For vining type squash or pumpkins, we suggest a threshold of 12 moths per trap per week. Vine-type cucurbits can root or tiller in at each node along the vine which allows the plant to take up water and nutrients from more than just the main stem. SVB tends to bore into the main stem of cucurbit plants, creating a higher risk for bush type plants.  Butternut and cucumber have some resistance to SVB. Target the base of the stem to treat newly hatched larvae before they bore into the stem. This pest is also becoming more prevalent in northern New Hampshire, where, historically, it was not a major issue. Our UNH Extension fact sheet is a great resource for this pest.

Table 2. Squash vine borer weekly summary, 7/21-7/25/2025.  

Spotted wing drosophila numbers continue to climb during peak berry season. If you have susceptible ripening fruit, I recommend monitoring for SWD. More information on monitoring for SWD can be found here. Frequent harvesting and placing berries in the fridge can help slow SWD development within the fruit. I also want to share this resource from Cornell on SWD management. It includes insecticides for each crop group that SWD may infest but be sure to check the label for use in NH.  Captures by crop are shown in Table 3 below. The control traps are located in unmanaged areas surrounding fields.

Table 3. Male SWD captures by crop, 7/21-7/25/2025.  

We have not caught any brown marmorated stink bugs yet this year.

Miscellaneous pest information: 

• Tarnished plant bugs have been very prevalent this year. I have observed them on multiple crops, including tree fruit and vegetables. Tarnished plant bugs can be a big problem for strawberries, but they can also damage beans, beets, cabbage, cauliflower, celery, cucumbers, potatoes, turnips, ornamentals, small fruit and tree fruit. TPB feeding could cause several types of injury including: dieback of the growing tip, death and drop of buds or flowers, brown scars on leaf ribs of lettuce, and distorted or stunted growth of leaves, pods, seeds, or fruit, scarred or dwarfed fruits, catfacing, and aborted fruit buds. Adults overwinter under bark, garden debris, and within clover, alfalfa, and mullein leaves. The adults become active in the early spring and attack the buds of early developing fruits. There are two generations per year in New Hampshire. Nymphs and adults cause similar damage to plants. Cultural controls: weed management, sanitation of crop debris to reduce egg-laying and overwintering locations, floating row covers, plant away from strawberries and alfalfa or clover if possible. You can scout for TPB from mid-April to early May, examine plants for bleeding wounds, brown discolored tissues, and other malformations. Also, look for adult TPBs on fruits, flowers, and foliage of susceptible crops. You can also monitor adults with white sticky cards (non UV-reflecting). More information can be found in our UNH fact sheet and in the NE Vegetable Mgmt Guide.

Adult tarnished plant bug on broccoli. Photo credit: Russ Ottens, University of Georgia, Bugwood.org

Tarnished plant bug nymph. Photo credit: Scott Bauer, USDA Agricultural Research Service, Bugwood.org

• Newly hatched hornworms have been observed feeding on tomatoes in high tunnels and greenhouses. See last week’s report for more information.
• Potato leafhoppers have been observed in multiple locations. More information on PLH can be found in our 7.14.25 report.  
• Previous vegetable pest and disease information can be found in past reports: https://extension.unh.edu/resource/vegetable-ipm-reports 

UPDATE on Cucurbit Downy Mildew – it is now in Connecticut, Pennsylvania, Long Island and Washington County NY, which borders VT. It has been documented on cucumbers and cantaloupe. This may be a good time to start scouting and make sure that you have any products ready for disease management. Storms could quickly bring it to New Hampshire. It would also be a good time to do any cultural practices to reduce humidity within the canopy such as pruning or staking plants.  

Disease of the Week: 

The disease of the week is late blight of tomatoes because it has been detected in Western New York and in Ontario. Late blight is a devastating disease of tomato and potato and is most famously known for causing the Irish potato famine of the 1840s. It is caused by the oomycete (or water mold) pathogen Phytophthora infestans. Symptoms usually first appear on younger leaves as irregularly shaped, water-soaked lesions, often with a lighter halo or ring around them. In high humidity, white cottony growth can be seen on the underside of the leaf. As the disease progresses, lesions enlarge causing the leaves to brown, shrivel, and die. Late blight can also attach the tomato fruit at all stages of development. On the fruit, symptoms appear as greasy spots that eventually become leathery and brown in color. It is important to note that these symptoms can be similar to symptoms caused by other Phytophtora species AND there are different strains of late blight that must be identified thus if you suspect you have late blight on your farm you must get it diagnosed as soon as possible as the spread of the diseases and management vary depending on the results.

Disease development is favored by cool temperatures (50s/60s at night and 80s in the day) and wet weather. Prolonged hot dry days can halt pathogen spread. Late blight does not always occur in New Hampshire every year. The most common form of introduction is on infected potato seed tubers or infected tomato transplants. Spores can also be windblown, moving from infected fields in the south northward.

Cultural practices that can control late blight include planting varieties that have resistance. Other cultural controls include providing good air movement around plants and reducing leaf wetness through proper spacing, staking or trellising of plants, pruning bottom leaves, and using drip irrigation. If late blight has been confirmed on your farm, it will be critical to destroy plant debris, volunteer plants, and weed hosts.

Fungicide applications can be made to prevent disease BUT it is important to note that late blight is a water mold and thus not a true fungus, so fungicides specific to water molds must be used. This can be another indicator that you have late blight on your farm if conventional fungicides do not work.

Orondis Opti (FRAC M05 + 49) and Orondis Ultra (49) are rated as excellent efficacy against late blight. Quadris Opti (11 + M05), Bravo products (M05), Presidio (43), Revus Top (3 + 40), and Zampro (40 + 45) are rated as good efficacy. FRAC Group 11 (Quadris F, Reason 500, Cabriolet, and Flint), Ranman (21), Curzate (27), Forum (40), Tanos (11 +27), Mancozeb products (M03), Previcur Flex (28), Zing! (22 + M05), and Gavel (22 + M03) have all been rated as fair efficacy against late blight based on the 2025 Southeastern US Vegetable Crop Handbook (page 293). Many fungicides should be tank-mixed with a protectant to get the best efficacy BUT read the label as some products, such as Gavel already contain a protectant (mancozeb).

Applying chlorothalonil (Bravo products) weekly starting before disease onset has provided good control in fungicide efficacy trials BUT this should only be done when the disease is detected in your region and the weather conditions are favorable to the disease. Late blight is extremely difficult to manage with fungicides once symptoms are detected, but Curzate and Tanos have some curative activity. Previcur Flex has good systemic activity, protecting the stems and new growth.

Importantly, the pathogen has become resistant to products with mefenoxam (Ridomil Gold Bravo SC and Ridomil Gold MZ) so other products must be used. More detailed fungicide information and options for conventional and organic commercial growers can be found in the New England Vegetable Management Guide. Other resources are the USABlight out of NC State and the report that came out of Ontario.

Late Blight on Tomatoes. Photo credit: Margaret McGrath, Cornell University, Bugwood.org

Late Blight on Tomatoes. Photo credit: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Upcoming events:

Tree Fruit Twilight Meeting @ Brookdale Farm
5:30 pm - 7:30 pm, August 20, 2025
Location: Brookdale Farm, 41 Broad St., Hollis, NH
More information here.