New Hampshire IPM Newsletter

Beetle on crop

The New Hampshire IPM Newsletter has been published by Alan Eaton, UNH Extension Entomologist, who retired in December. (For NH IPM Newsletter posts from years prior to 2018, see the NH Integrated Pest Management Newsletter Archives). 

For news related to IPM in Vegetable and Fruit Crops, please visit NH Vegetable & Fruit News. Published by our Vegetable & Fruit Team, this blog shares the latest news and research about vegetable and fruit production in the state and beyond.

Fruit Pest Hotline Transcripts

August 12, 2019

DD accumulation since 1Jan in Durham (base50) = 1554

I expect that early maturing apple varieties are coming in soon. Apple Maggot populations may have peaked in many areas but continue to monitor traps, even if you have already treated. Consider a border spray instead of the full field if you hit threshold again.

Redbanded leafroller flights subside between 1400-1800 GDD, while obliquebanded leafroller’s second flight starts somewhere around 1400-1800 GDD.

We here at extension are monitoring populations of brown marmorated stinkbug. I haven’t seen anything that would raise alarmbells yet but consider making sure you know what they look like. The dead give away, especially on nymphs is the white bit in between antennae or leg segments. To me it looks like a farmer’s tan but kind of like on their knees…if that makes any sense. Stayed tuned for more from us if we detect anything worrisome.

SWD populations have reached that point when we stop monitoring traps and consider all ripe thin-skinned fruits at high risk for SWD infestation. Weekly treatment is recommended for blueberries and at least weekly treatment for raspberries and blackberries. Consult your guide for information on crop protection materials and make sure to rotate classes. Post-harvest handling can be very important for light infestation so harvest often and refrigerate as soon as you can for as long as you can. Most eggs and small larvae will be killed by several days at 34F. Urge pick-your-owners to refrigerate or freeze whatever they don’t eat the day they pick.

Something else you can be on the lookout for in blueberry this time of year is blueberry stem gall wasp, which sounds like its showing up here and there. Tiny wasps lay eggs plants during the spring and their offspring develop in kidney-shaped galls. The galls turn red by this time of year and turn brown/black when the plants go dormant. Galls can be pruned out during the winter but they’re the most conspicuous during this time of year.

 

August 5, 2019

DD accumulation since 1Jan in Durham (Base50) = 1426

We’re in the home stretch for apple pests and not too much to report this week. Fair weather has made for low disease pressure but may make good conditions for mites. Threshold for mites is generally 7.5 mites per leaf. Apple maggot traps should be checked regularly. Threshold is 5 flies/trap with a lure, 1 fly/trap without a lure.

It sounds like peach harvest is starting in some varieties. Peach tree borer flights are likely subsiding.

SWD populations have reached that point when we stop monitoring traps and consider all ripe thin-skinned fruits at high risk for SWD infestation. Weekly treatment is recommended for blueberries and at least weekly treatment for raspberries and blackberries. Consult your guide for information on crop protection materials and make sure to rotate classes. Post-harvest handling can be very important for light infestation so harvest often and refrigerate as soon as you can for as long as you can. Most eggs and small larvae will be killed by several days at 34F. Urge pick-your-owners to refrigerate or freeze whatever they don’t eat the day they pick.

July 30, 2019

DD accumulation since 1Jan in Durham (base50) = 1260

We expect apple maggot peak catch somewhere between 1430-1800 GDD but as a reminder, apple maggot thresholds are 5 flies per trap, if you are using a lure. If you are not using a lure, the threshold is an average of 1 per trap.

This hot weather could be favorable for red mites. Threshold is generally 7.5 mites per leaf.

Peak flight for codling moth is expected somewhere around 1300-1800 GDD, so likely sometime this week. Redbanded leafroller’s second generation peak flight is likely winding down now.

SWD numbers are approaching their exponential climb and we are detecting low infestations in most locations throughout the state. Ripe fruit should be protected from egg-laying from here on, especially in raspberry. Post harvest handling can be very important for light infestation so harvest often and refrigerate as soon as you can for as long as you can. Most eggs and small larvae will be killed by several days at 34F. Urge pick-your-owners to refrigerate or freeze whatever they don’t eat the day they pick.

For those of you who know a new farmer, let them know that New Farmer school is starting in August. Registration is $250 (scholarships available) for 6 sessions through the fall months and topics cover a diverse array of topics critical to starting a farm business.

 

July 22, 2019

DD accumulation since 1Jan in Durham (base50) = 1124

Keep your eyes peeled for fireblight strikes, pruning out when you need to. Keep checking your apple maggot traps. I’ve been hearing low numbers so far but, like everything else this year, their development might be delayed. All the more reason to monitor your own pest populations. Threshold trap numbers are an average of 5 apple maggot flies per trap, if you are using a lure. If you are not using a lure, the threshold is an average of 1 per trap. Consult your guide for protection materials.

San Jose scale’s and codling moth’s second generation flight normally starts somewhere around now, 1050- 1300 GDD for male scale insects and 1030-1500 GDD (base 50) for codling moth. Speaking of codling moth, Jaime Pinero at UMass is interested in testing local populations of codling moth and oriental fruit moth for signs of chemical resistance. So if you find any fruit with internal feeders, think about hanging on to those and give me a call or an email. Anna.Wallingford@unh.edu. While, it might be too late to treat for many of the major leafrollers, their damage becomes more conspicuous in the orchard around now. Scouting to identify problems early might be a good idea.

Strawberry growers, prompt renovation is critical to getting your strawberries ready for overwintering and next year’s fruit set. If you have a history of black vine weevil, controlling for this pest during renovation can be important to limiting their spread. If not, its always a good idea to scout new growth after renovation for their feeding, characteristic notching on leaves.

SWD trap numbers are slowly climbing and I’ve detected some light larval infestation from fruit collected here at our research farm, so it’s time to start protecting ripe blueberries and raspberries from SWD egg-laying as they come in. Consult your guide for protection materials and consider more than one option as class rotation for resistance management is important here. Also, considering this has been a particularly bad year for mummyberry, getting dropped fruit out of blueberry plantings could be a worthwhile activity to reduce SWD habitat and reduce mummyberry inoculum for next year.

For pumpkin growers - Squash vine borer numbers remain very high! Consult the weekly scouting reports to see the pest pressure nearest you and consult your Veg guide for crop protection materials.

July 15, 2019

DD accumulation since 1Jan in Durham (base50) = 947.

Apple maggot is likely active now. Threshold trap numbers are an average of 5 apple maggot flies per trap, if you are using a lure. If you are not using a lure, the threshold is an average of 1 per trap. Consult your guide for protection materials.

Codling moth’s first generation is likely subsiding now, while obliquebanded leafroller is likely flying now and Oriental fruit moth will likely be starting its second flight soon.

For grape growers, now would be a good time to scout clusters for signs of grape berry moth infestation. Treatment might be considered if more than 6% of clusters are damaged by larvae and that treatment should be timed for about 800 DD after biofix. Biofix is the date you first trapped grape berry moth on your farm or, for this particular species, when you notice wild grapes blooming. For example, biofix occurred around the middle of June in Durham, so we are about 655 GDD from biofix with a few hundred more GDD to accumulate before treating for second generation larvae.

Japanese beetles and their cousins are flying now. This group, aka scarab beetles, spend most of their life below ground as white grubs that eat grass roots. They emerge once every year to eat just about everything and make big gross cuddle puddles everywhere before returning to the ground. I know it’s hard to hear because they are so conspicuous but, unless you are protecting young or stunted plants or you see that fruit is being affected, this group rarely does enough foliar damage to justify treatment of mature plants. If you do treat, be mindful that certain broad-spectrum insecticides, pyrethroids in particular, can cause secondary outbreaks of pests like aphids when they are used repeatedly.

SWD has been detected in several locations in southern New Hampshire but in very low numbers and has not yet been detected in fruit.

For any pumpkin growers, squash vine borer monitoring in the state continues to find very high numbers.

As far as events go, Steve Roberge is giving at tick talk at the Olivia Rodham Memorial Library in Nelson on Thursday evening at 7pm. There are swine producer’s field days this week so please contact 603-679-5616 for more information on that.

July 8, 2019

DD accumulation since 1Jan in Durham is (base 43) = 1350, (base50) = 793.

Expect apple maggots to start flying between 760-1200 GDD (base 50). Hang three volatile-baited sphere traps on the outside row facing the most probable direction of AM migration (towards woods or abandoned apple trees, or else on the south-facing side). Check traps regularly, once or twice a week, to get a total number of flies caught; and a spray is advised when average is 5 or more. If you are not using an attractive lure, this threshold is 1 fly per trap. The adult fly is ¼ Inch long, smaller than a common housefly. It’s black with white lines on its abdomen and its wings have zig-zaging black bands.

Comstock mealybug flight peak occurs between 931-1143 GDD (base 50), so those of you who are planning on targeting summer crawlers should put out tape traps soon. You will be looking for tiny orange nymphs to time your spray. Consult your guide for protection materials.

It’s a good time to scout for fireblight strikes and remove infected tissue from the orchard. Remember to cut at least 12-18” below infected area, leave a stub rather than cut all the way back to the healthy limb, and to sanitize tools between cuts to avoid spreading the pathogen.

While you’re out there, now is also a good time to scout for mites affecting apple – look for bronzing on leaves then look closer for mites on the undersides of leaves. The threshold is 5 active mites per leaf but remember, spot treatment might be an option for areas where you missed an oil treatment in early spring.

For small fruit growers, SWD has been detected in the state but in very low numbers and no fruit infestation has yet been observed.

For curcubit growers, squash vine borer is flying and it looks like numbers are quite high. Consult your veg guide for crop protection options.

There is a Tree Fruit twilight meeting Wednesday July 10th, 5:30-7:30 at Sunnycrest Farm, located at 59 High Range Rd, Londonderry, NH 03053. Orchard Weed Sprayer calibration. Two Pesticide Applicator recertification credits will be available.

July 1, 2019

DD accumulation since 1Jan in Durham is (base 43) = 1134, (base50) = 626.

Severe storms were reported in southern New Hampshire over the weekend. Damaged apple and pear trees should be treated with a streptomycin product within 24 hours to prevent fireblight transmission through open wounds in those trees. With regular wet weather, NEWA models also predict high risk levels sooty blotch and flyspeck infections so consult your management guide for crop protection materials.

Codling moth are likely flying in apple orchards now, so control of larvae could be warranted. In particularly high pressure situations, time a second spray 10-14 days after the first and rotate material to avoid chemical resistance. Apple maggot emergence is expected soon – at around 800-1300 GDD (base50) – so get monitoring traps ready.

Peach trees damaged by weather events are susceptible to fruit rot fungi so a high rate of Captan is recommended to keep spore build up in check. Those of you monitoring for peach tree borer should have your traps up by now as we expect flights to begin in July.

With the delay in the season, it’s possible that late maturing strawberries may be affected by spotted wing drosophila this year. SWD was not detected in our traps last week but expect updates to this soon.

There is a twilight meeting at 5:30 tonight (July 1) in Litchfield NH at Wilson Farm on Charles Bancroft Highway to e wildlife concerns for vegetable and small fruit crops, with pesticide applicator credits.

A tree fruit twilight meeting will be held next Wednesday July 10 at Sunnycrest Farm in Londonderry, with PAC, featuring orchard weed sprayer calibration, irrigation systems, and mid-season IPM topics.

Tonight and tomorrow night our dairy livestock and forage crops team will be hosting mid-season corn check up and pest scouting events held at 11am in Woodsville and Penacook. PAC. Contact 352-4550 for more information.

June 25, 2019

DD accumulation since 1Jan in Durham is (base 43) = 984, (base50) = 518.

San Jose scale male flight is likely wrapping up at somewhere between 515-769 GDD (base 50), which means the first generation of crawlers is likely to become active soon. Usually looking at 619-757 accumulated growing degree days. Consult your guide to select crop protection materials for trees where you saw damage last year.

Get ready for apple maggot season as these flies will be emerging from their overwintering habitats soon. Traps for monitoring can be purchased from GreatLakesIPM, Gemplers, Ladd Research Industries. There’s a bit of a philosophical divide over whether or not to use an attractive bait on red sticky sphere traps. Some fear that the odor pulls in more flies, so they opt you use the traps by themselves. However, the odor makes the traps much more sensitive, so you don’t need to put out as many to get a good read of AM activity in your orchard – maybe three per block with the lure. If you are relying on the visual cue alone make sure to use several more traps to read activity through out the orchard.

Peach tree borer is likely starting its flight period around now, expected to start around 448-812 GDD.

We have not yet detected spotted wing drosophila in our traps but areas to the south of us have consistent detection so I expect them to show up in New Hampshire any day now. Protect ripe fruit when flies are present on your farm.

Events:

Equipment Demo Day for Vegetable Producers Wed, 06/26/2019, 4:30pm - 7:30pm UNH Woodman Farm, Spinney Lane, Durham, NH 03824. NHSoilHealth.org or by calling (603) 749-3037.

Addressing Wildlife Concerns for Vegetable and Small Fruit Crops - Farm Twilight Meeting, Mon, 07/01/2019, 5:30pm - 7:30pm, Wilson Farm NH, Charles Bancroft Hwy (Route 3A), Litchfield, NH 03052, Two pesticide credits will be available.

Our Dairy and Livestock Team are hosting  a Mid-Season Corn Checkup and Pest Scouting, Tue, 07/02/2019, 11:00am - 1:00pm, Morrill Farm, 43 Rolfe Street, Penacook, NH, Pesticide Applicator Credits & VT Water Quality Credits pending. RSVP Appreciated. For questions, special accommodations, or to rsvp contact: Carl Majewski at (603)352-4550 or carl.majewski@unh.edu.

June 17, 2019

DD accumulation since 1Jan in Durham is (base 43) = 795, (base50) = 386.

This is certainly a challenging year for apple scab. As you’re planning your crop protection approach for secondary infection period, remember that fungicides control disease in different ways. Protectants must be applied before infection occurs, so before infection periods caused by rain or wetness. Some fungicides can suppress production of conidia from recent infections (i.e. those with “kickback”) but those with post-infection activity must be applied within a narrow time after the beginning of an infection event.

Plum curculio is likely still laying eggs in tree fruit but winding down as codling moth is flight and egg laying is likely winding up. The first generation of San Jose scale crawlers are likely being  produced. Consult your tree fruit guide for crop protection strategies.

For peach, fruit are susceptible to catfacing insects like tarnished plant bugs and other piercing sucking insects. Lesser peach tree borer is likely flying now. This species of peach tree borer is less a threat to trees as greater peach tree borer, which starts flying a little later in the summer. LPT tends to damage smaller, more distal branches compared to attacking the main trunk, but very high populations might warrant action. Consult your guide.

For strawberry, now might be a good time to release spider mite predators as two-spotted spider mite populations are growing. I’ve heard reports of outbreaks here and there, even though this spring hasn’t been providing what we consider ideal conditions for mites. Once fruit sets, strawberry sap beetle, anthracnose, and botrytis are going to be concerns. Strawberry sap beetle is a little black nocturnal beetle that damages ripe strawberry fruit when it goes after the seeds so the damage might easily be confused with slug damage. Make sure you know who you’re dealing with before acting.

Potato leafhopper might be a problem in small fruit this year – remember that this insect overwinters in the gulf states and migrates here, arriving in the northeast by late June or early July. So even though, we’ve had a slow moving season up here, that doesn’t affect potato leafhopper. Piercing-sucking feeding, and injection of toxic saliva, results in hopperburn on leaves. This looks like discolored, crinkled, sometimes downward curling leaves. Look for these symptoms and check on the underside of leaves for the leafhoppers to confirm. There’s no hard threshold but younger, delayed, or stunted plants are more susceptible, so keep an eye out and consult your small fruit guide to select your plant protection approach.

Events: Equipment Demo Day at Woodman Farm in Durham for Vegetable Producers next Wednesday (6/26) 4:30pm - 7:30pm. Featuring a two-wheel BCS tractor with various implements useful for vegetable growers, a no-till transplanter for planting and optimizing soil health, and tarping and roller crimper techniques for terminating cover crops. I believe some of this equipment can be loaned from your conservation district if you’re interested in adopting no-till practices so come and check it out. More information at NHSoilHealth.org or by calling (603) 749-3037.

There will be a twilight meeting July 1, addressing wildlife concerns for veg and fruit growers in Litchfield NH.

June 11, 2019

DD accumulation since 1Jan in Durham is (base 43) = 684, (base50) = 316.

We’ve been enjoying some lovely weather but it looks like rain is in the forecast this week. Scout for apple scab lesions and keep an eye on those apple scab models, with your risk levels in mind.

Plum curculio is likely laying its eggs in apple orchards now, so continue to scout for fresh oviposition scars to determine whether or not to treat. I heard some reports of first capture of codling moth adults last week, so right on time according to degree day estimates. Ovicides for codling moth should go out now.  Treatments for codling moth larvae should be timed for egg hatch, which occurs about 220 DD (base50) after first trap catch.

Reports of SWD first trap capture continue to roll in from areas south of us here in New Hampshire so, if you are monitoring for SWD in crops like strawberry, blueberry, and summer raspberry, you should get those traps out soon.

For those of you with serious winter injury to your blueberries, FSA is considering a disaster relief program so reach out to me or to your county specialist if you think this would be helpful to you.

Grapes: Peak flight of the overwintering generation of grape berry moth normally occurs at 350-400 GDD, this also often coincides with wild grape bloom. So keep an eye out for that if you know you have a

There is a tree fruit twilight meeting scheduled for this Wednesday, June 12th at Meadow Ledge Farm, 612 NH-129 Loudon, 5:30-7:30. Pesticide applicator credits will be available. Special Topics:  BMSB Trapping, Apple Processing, USDA Wildlife Service.

June 3, 2019

DD accumulation since 1Jan in Durham is (Base43)= 536, (Base50) = 224. Many apples are at post petal fall. Fruitlets are sizing up quickly and are susceptible to plum curculio so now is a good time to get out and scout for oviposition scars. According to the models, apple scab primary infection period is over in most areas. Now might also be a good time to scout for apple scab lesions on leaves and on fruits. Walk a transect through the orchard and examine the leaves and fruits of at least 10 clusters on at least 10 trees.

First capture of codling moth, or CM “biofix” normally occurs around now 200-300 GDD (base 50), but timing codling moth treatment is best when you have first catch data for your own farm. If you are using an insecticide that needs to be present before egg laying, it should be applied about 50-75 DD after first capture and if you are targeting young larvae, eggs normally hatch after about 220 DD after first capture.  

The same goes for San Jose scale, where treatment for crawlers should be timed at roughly 310 GDD after first capture of flying males. That first flight should be happening soon between 300-400 GDD from Jan1, but trapping is the best way to know what’s going on at your farm.

Reports of SWD first trap capture are rolling in from areas south of us here in New Hampshire so, if you are monitoring for SWD in crops like strawberry, blueberry, and summer raspberry, you should get those traps out soon.

For strawberry, keep scouting for tarnished plant bug during bloom. Threshold is reached if 4 or more flower clusters are infested with nymphs out of 30 clusters sampled evenly from across the field…and keep an eye out for thrips as these guys might come out while you’re tapping those flower clusters. Look for spider mites on the undersides of leaves and keep a record of hot spots that might need attention later as conditions warm up and dry up. The action threshold is when 25% (i.e., 15 leaves) or more of a 60 leaf sample is infested.

It sounds like orange rust of brambles could be a problem with the wet spring we’ve had so if you come across this you should cull out affected plants.

Events in the near future: there is a tree fruit twilight meeting scheduled for next week, June 12th at Meadow Ledge Farm in Loudon, 5:30-7:30. Special Topic:  BMSB Trapping, Apple Processing, USDA Wildlife Service. Pesticide applicator credits will be available.

May 28, 2019

We’ve been enjoying some beautiful weather here in the Durham area. DD accumulation (Base43)= 468, (Base50) = 195. Many apple varieties and blueberry varieties are still blooming.

According to the NEWA model apple scab ascospore maturity is at 99% so primary infection period is wrapping up, but there is rain in the forecast for many areas of the state so not quite out of the woods yet for potential infection periods.

Hopefully you’ve been checking your fireblight risk models regularly while your apple trees are blooming, especially if you had fireblight in your neighborhood last year. It’s supposed to rain in Durham this afternoon so today’s risk for fireblight infection is extremely high here. If I had trees in bloom here, I would want to get an antibiotic on today or tomorrow.

Planning for petal fall, this period is the best time to consider controls for plum curculio, European apple sawfly, obliquebanded leafroller, codling moth, European red mite. Plum curculio is likely already active in your orchard but females will start laying eggs in fruit once they get to be about a quarter of an inch in diameter. Look for fresh oviposition scars to trigger a control measure and consult your guide for selecting crop protection materials. Continue to scout for those fresh scars over the following weeks and consider a border spray for subsequent controls as this is normally sufficient.

For peaches, lesser peach tree borer starts flying around 476-668 (base 43), 250-370 (base 50). So if you are monitoring for borers, your traps should be up by now.

Once strawberry starts blooming, scout for tarnished plant bug by shaking flower trusses over a flat white surface. Alan Eaton always had a white Frisbee to do this but a white piece of paper will do. Tarnished plant bug nymphs are small and bright green. They kind of look like an aphid but they’re a lot more active, meaning they’ll run off that white paper pretty quickly. Threshold is reached if 4 or more flower clusters are infested with nymphs out of 30 clusters sampled evenly from across the field.

As far as events: we have another Tree Fruit Twilight meeting scheduled for June 12 at Meadowledge Farm in Loudon. If you missed our last meeting at Patch Orchard in Lebanon, so did I. George, Jeremy, Heather and I recorded a quick conversation where they caught me up on what we missed. I’m sending out an email with the link to this recording via the NH Vegetable & Fruit newsletter list so look for it later this week. If you’re not signed up for the newsletter, you can find directions for this on the extension website. Let us know if you’d like us to do more stuff like this.

May 21, 2019

We have many apple varieties blooming in the Durham area, as well as early varieties of blueberry. Peaches are still in bloom. Durham (Base43)= 343, (Base50) = 120.

For those who had fireblight in their neighborhood last year, check fireblight risk models on the NEWA website regularly while your apple trees are blooming. Our model for Durham says trees are at moderate to high risk and a bactericide should be considered.

Apple scab ascospore maturity is predicted to be at 91% in Durham so we are nearing the end of primary infection, but there is more rain in the forecast so continue to keep up with apple scab protection.

The same goes for brown rot and bacterial spot in peaches. Brown rot susceptibility starts to decline after shuck fall but considering all this rainy weather this will be a problem for many of you.

For those of you who monitor codling moth, you should have your traps up by now. First trap is anticipated around 200-300 DD(50) and that first capture establishes a biofix. This biofix is important for subsequent degree day accumulation that predicts peak CM flights on your farm through the year.

For many small fruit growers, we’ve been seeing and hearing about lots of winter kill in blueberry and raspberry. There’s a little discussion about whether or not to prune out dead wood in blueberry but you should probably hold off from pruning to wait and see if these dead canes are just delayed.  We’ll be providing more detailed guidance for this in a few weeks but for now, hold off on pruning and continue with your normal fertilization plans.

Mummy berry strikes may be showing up in blueberry soon. Consult the small fruit guide for more details on how to manage outbreaks.

Strawberry is also still wait and see as far as winterkill but this wet spring will produce perfect conditions for problems with Phytopthora infections. Red stele is caused by Phytopthora infections and symptoms are numerous and may be easy to confuse with winter injury: wilting; young leaves with a bluish-green tint; and older red, orange or yellow leaves. As plants progress and conditions dry up, severely diseased plants may die or remain stunted, producing few runners and small berries. Plants showing symptoms usually occur in patches where the soil was the wettest. When roots are cut open lengthwise, the core will show a reddish-brown discoloration; however, a reddish core does not guarantee that it’s red stele or Phytopthora – so send in samples to the diagnostic lab if you haven’t had this confirmed. If you know you have a history of red stele, consult your guide for protection recommendations.

Events: there is nothing from the Veg & Fruit Team in the immediate future but there is a backyard chicken basics workshop tonight, 6 pm at the Nesmith library in Windham, NH, for anyone interested.

May 14, 2019

Here in Durham, apples are at pink and peaches are in bloom. Durham (Base43)=250, (Base50) = 72

Apple Scab: For Boscawen: 61% mature ascospores (southern areas will be ahead, northern areas behind). Although many of the mature ascospores have been discharged, a scab infection period is predicted for the 14th. So, if you did not have a fungicide on prior to the infection, consider a kickback fungicide, especially if you had scab in the orchard last year.

Telial horns on cedar apple rust galls are still active.

Fire blight: With the southern portions of NH reporting some blossoms open on Macs (and earlier varieties), it’s time to monitor NEWA for fire blight. Go to newa.cornell.edu and click on apple diseases under the pest forecast tab. Select fire blight, NH, and the weather station closest to you. The date defaults to the current days date. When the model opens, select your orchard blight history, and enter the date of first blossom open. Hit the calculate button. The model will give you the current risk, and 5-day forecast.  The next few days will be too cold for infections, but keep monitoring the situation.

Pink stage is the last time to check for little green pug moth larvae and rosy apple aphid colonies – these can be yellow or powdery blue or pinkish. Act before bloom and before leaves surrounding blossoms curl up and around fruit clusters, thereby providing protection from sprays. Tarnished plant bug is likely moving into orchards soon and you might consider using white sticky traps to assess density. Redbanded leafrollers and spotted tentiform leafminers are flying. Peak flight for RBLR occurs at roughly 105-200 GDD (50), STLM at roughly 124-212. GDD (50).

For peaches: bloomtime is a good time to act for brown rot treatment, especially if you had brown rot problems last year…which is most of us. Consult the tree fruit management guide for product selection.

Raspberry and blackberry: we’ve seen a bit of winter damage on summer fruiting varieties and this may mean variable or delayed shoot growth along the cane.

For blueberry:  If you had problems with mummyberry last year, be sure to get 2” of mulch down ASAP (if you have not done so already).

There is a tree fruit twilight meeting this Wednesday on May 15th at Patch Orchard at 40 Patch Rd. in Lebanon, 5:30-7:30pm with an opportunity to earn pesticide applicator credits. For anyone interested in buying a hardcopy of the new Tree Fruit Management guide, you should be able to pick one up at this meeting or contact me at Anna.Wallingford@unh.edu or 603-862-1734. Hardcopies are $25 but the guide is always available online for free. For those of you that volunteer to monitor conservation easements in your area, extension is hosting a workshop this Saturday in New Durham – so check out the website for details.

May 7, 2019

Things are moving along nicely here in Durham. Apples are at tight cluster for the most part, however I’ve seen a little early pink, blueberries are at tight cluster, and peaches are in bloom.

In anticipation of apple bloom, if you had fireblight in your neighborhood last year, consider making sure you have a streptomycin product on hand. As we watch for risk indicators of blossom blight infections to come, it is best to be prepared.

Apple scab ascospore maturity is estimated to be 38% and the recent wet weather has provided prime conditions for infection events. You may want to take advantage of this nice weather and get a protectant fungicide on before the rain predicted for Thursday and Friday or make sure to have materials with some kickback on hand.

Cornell has just launched a new tool on their NEWA website to help with timing your thinning efforts. This tool can be found under the crop management drop down menu – its called “Apple CHO v2019” -and differs from the old model in a few ways. You can enter information about the flowering status of your crop to improve the precision of this decision making tool. Check it out at NEWA.cornell.edu.

For peach, bloom time is a good time to apply a fungicide for brown rot, especially if you had brown rot issues last year and did not take extensive sanitation measures over the dormant period. Tart cherries are also particularly susceptible to brown rot. Consult the tree fruit management guide for more information on selecting a product.

If you are using mating disruption for peach tree and lesser peach tree borers and haven’t put your ties out, they should go out soon.

Speaking of mating disruption and bouncing back to apple for a moment – we have news that NH registration was approved on CIDETRAK mating disruption products for codling moth and oriental fruit moth CMDA+OFM MESO, OFM-L MESO and DA MEC. So ask your supplier about that if you are interested but ask soon if you want to act this year because mating disruption has to go out before moths start flying.

In strawberry fields where Strawberry Bud Weevil/Clipper were a problem last year, now might be a good time scout fields as flower trusses emerge and expand for sign of this pest.  In the pre-bloom to early bloom period female clippers lay an egg in an unopened flower bud and then clip the stem of the bud causing it to flop over or fall off, obviously causing the loss of that fruit. Clipper tends to be a more severe problem along borders of plantings, near woods, hedgerows or stonewalls. Treat for clipper when you find an average of more than 3 highly damaged flower trusses per meter of row. You might consider only treating border rows, especially rows bordering woods, hedgerows and stonewalls. Do not treat during bloom.

For brambles - As leaf tissue expands, watch for orange rust on blackberries and black raspberries and rogue out plants where it is found.  Orange rust is systemic and cannot be treated to eliminate it from an infected plant.

Next week there will be a tree fruit twilight meeting on May 15th at Patch Orchard at 40 Patch Rd. in Lebanon, 5:30-7:30pm with an opportunity to earn pesticide applicator credits.

April 30, 2019

There has been quite a bit of variability in fruit tree development depending on where you are in the state and the microclimate on your farm. GDD (base 43): Durham – 172 (last year 105), Hollis – 216 (last year 124)

Our plant pathologist, Cheryl Smith has reported that Jellie horns are out on cedar apple rusts so trees are at risk of infection with rains. In Durham, we estimate 11% apple scab ascospore maturation. This, as well as lots of rain, puts apple orchards at high risk of apple scab infection. Consult your management guide for crop protection materials.

Now until pink would be a good time to scout apple orchards for the presence of winter moth or green pug moth larvae. This can be done by observing fruit buds for caterpillars or by tapping branches with fruit buds onto a white surface. Presence of these sporadic pest species may trigger an insecticide treatment before bloom. Insecticide sprays during bloom are discouraged in order to avoid negative impacts on pollinators in the orchard. However, there are selective insecticides (like Dipel) which have efficacy on caterpillars like winter moth and pug moth but little effect on pollinators.

For blueberry – wet weather means continued risk for mummy berry infection. Cleaning up fallen mummies, or covering them with at least 2” of mulch is a helpful sanitation practice. Consult the guide for effective fungicides.  If your blueberry plants are affected by any species of scale insect, a dormant or delayed-dormant oil spray may still be appropriate. If you do have green tissue, make sure the oil product you are using specifically allows for delayed dormant applications.

For strawberry – As foliage expands, now is a good time to start tracking weak areas of the field and check roots for Black Root Rot or signs of Red Steele if you find stunted or sparse growth. Check the extension websites for details on how to submit plant samples to the diagnostic center if you think you have a disease problem, but best management practices call for proper nutrition and proper timing of renovation to allow for good winter preparation in the fall.

Events - It sounds like registration is full for the Women’s Farm Equipment Field day on May 4th but you can contact elaina.enzien@unh.edu or (603) 679-5616 to see if there’s room for you, or to encourage more events like this in the future. Looking well ahead on the calendar there will be another tree fruit twilight meeting on May 15th at Patch Orchard in Lebanon, with opportunity to earn some pesticide applicator credits.

April 22, 2019

Degree day accumulation is 135 in Durham. Depending on the weather conditions at your site, you should be seeing some green tissue in apple orchards and therefore susceptibility to apple scab infection. Ascopore maturity is moderate – 4% - however rain events, temperature, and leaf wetness hours over the weekend provided ideal conditions for ascospore infection events. If you were not able to apply a preventative product, you might consider a fungicide with some kickback. Unless you are sure your risk is very low - meaning you had little scab last year and passed a PAD count last fall.  Consult the NE Tree Fruit guide for help selecting a product.

You might consider putting out white sticky traps to monitor for tarnished plant bugs entering the orchard. Hang them about knee height on the south side of trunks and above grass rather than bare ground as they will be moving from grass into trees. These piercing-sucking feeders will feed on developing fruit buds early in the season and cause cosmetic damage to fruit later in the season.

Now until pink would be a good time to scout apple orchards for the presence of winter moth or green pug moth larvae. This can be done by observing fruit buds for caterpillars or by tapping branches with fruit buds onto a white surface. Caterpillars will be knocked off and easier to see on the white surface of say – a white Frisbee? Presence of these sporadic pest species may trigger an insecticide treatment before bloom.

For blueberry – the recent wet weather means that any green tissue that may have emerged this week may be susceptible to mummy berry infection. If your blueberry plants are affected by any species of scale insect, a dormant or delayed-dormant oil spray may be appropriate. If you do have green tissue, make sure the oil product you are using specifically allows for delayed dormant applications.

It sounds like registration is full for the Tree Fruit Grafting workshop in Goffstown on Wednesday but you can contact Mary West at 796-2151 to see if there is room for you. There are pruning demonstration workshops coming up soon. Blueberries and raspberries this Saturday afternoon at Pratt Berry Farm in Lancaster NH. Ornamental trees and shrubs this Saturday at UNH’s Woodman farm in Durham. Looking well ahead on the calendar there will be another tree fruit twilight meeting on May 15th at Patch Orchard in Lebanon, with opportunity to earn some pesticide applicator credits.

April 18, 2019

Reports of green tip have been coming in from southern regions of the state. With rainshowers predicted in this weekend’s forecast, those apple growers with green tissue showing may want to apply a protectant fungicide due to high risk of apple scab infection.

April 15, 2019

Growing degree day accumulation for Durham 68, Hollis 82. We’re seeing swelling buds but no green tissue yet. 

Risk models for primary infection period for apple scab begin when 50% of macs are at green tip so that’s when we start looking at risk for infection events.

It’s pretty muddy out there but you should be thinking about getting in an application of dormant oil between green tip through tight cluster for smothering overwintered mite eggs and overwintered San Jose scale. Large spray volumes are recommended for getting really good coverage and the standard rate is 2 gallons per 100 gallons of water until half-inch green or 1 gallon per 100 gallons of water at tight cluster. The lower concentration lowers risk for phytotoxicity as more new growth emerges. Applying dormant oils with 48 h of freezing temperatures should also be avoided, or you could use a lower concentration, and it looks like that won’t be an issue in the upcoming weeks, but you never know these days, so keep an eye on your forecast.

There is a Tree Fruit twilight meeting at Butternut Farm on Wednesday April 17 from 5:30-7:30 pm, 195 Meaderborough Road, Farmington, NH. That will come with 2 pesticide credits.

Other opportunities for earning pesticides credits, and for brushing up on your pruning techniques: There are pruning demos and grafting workshops coming up with Saturday April 20 in Tuftonboro and next Tuesday April 23 in Hillsboro. Check out extension.unh.edu for more information.

April 8, 2019

Still not too much to report. Degree days accumulation as of today is 40 at Durham, 49 at Hollis.

The wet weather this week will make getting into the orchard a challenge but you may still have time to apply a dormant fungicide in peaches that were affected by peach leaf curl last year if you did not spray for it before leafdrop last fall.

For blueberry growers with a history of mummy berry, it might be a good time to rake mulch in blueberry plantings. A 2” layer of new mulch is enough to burry the mummies on the ground. Those mummies sources of fungus spores and new infections this year.

There will be a twilight meeting for commercial tree fruit growers next Wednesday the 17th at Butternut Farm in Farmington at 5 pm. For more information, visit extension.unh.edu

April 1, 2019

Not much to report yet, we’ve accumulated roughly 33 degree days here in Durham, 35 in Hollis.

But this is a good time to consider delayed-dormant sprays of petroleum/dormant oil (green tip through tight cluster). Large spray volumes help with good coverage, which is particularly important for smothering overwintered mite eggs and the nymphs, or “crawlers”, of San Jose scale and Comstock mealybug, which start moving around this time of year.

UNH pesticide safety training will be offered in Dover for prospective private and commercial applicators starting next week. Find more information at our website: extension.unh.edu.