IPM and the Home Garden

Since the discovery of pesticides during World War II, most growers have relied heavily on there use to prevent pest damage both commercially and in home gardens. Often, these chemicals are applied at specific times of the year according to a pre-set schedule and not because there is a need. After years of using pesticides in this manner, a number of challenges have been created: pesticide resistant pests, concerns about negative effects of pesticides on beneficial or non-target organisms and environmental health concerns.

 

So what can a grower do? Many growers are shifting to and using a different approach for managing pest problems in the garden. This change is known as IPM or Integrated Pest Management. This not so new program combines many different management strategies to achieve long-term solutions to pest problems while using fewer pesticides. This decrease in pesticide use lessens the impact on non-target organisms and the surrounding environment.

 

Pest management practices can be divided into long term preventive practices and short term control treatments. Long term preventive practices may include the use of resistant plant varieties, appropriate cultural practices, practices which conserve natural enemies of the pest and modification of site conditions to make the area less attractive to pests. Short term control treatments include biological, physical and chemical control.

 

To plan an effective pest management program the grower must first accurately identify all pests and suspected pests and then become familiar with their biology. Being able to sort out the real pests from non pests can be critical to the success of the program. Closely examin all parts of the plant and observe the effects of the problems: When did the problem first start? Is the normal growth pattern of the plant affected? How much of the plant is affected? Are there color changes, and what is their pattern? Are older or newer leaves more affected? For leaf spots, be sure to look at both sides of the leaves. Is there evidence of an insect or an animal (droppings, old insect cases)? Are there parts of the plant missing? What is the pattern of that damage?

 

Monitoring pest populations should be done regularly to keep abreast of developing pest problems and to determine population levels of their natural enemies. It is very important to remember that not all insects found in the garden are pests. Lady beetles, lacewings, mantids, parasitic wasps, and soldier beetles are just a few of the beneficial insects that may be found. Ideally, a healthy balance of beneficial insects and pests should be present. Regular monitoring ensures that developing pest problems are caught early and can be treated before they spread to a wider area or there is a high level of damage. At the heart of IPM is the understanding that many crops can tolerate a certain amount of pest damage.

 

There are many pest management preventative practices that can be considered in reducing pest populations, but not all practices are appropriate for all situations. Cultural control is the most widely used method of reducing pest damage. It is based on the fact that healthy vigorous plants are less susceptible to damage from pests. Cultural practices include any thing that involves manipulation of the growing conditions to make the system less favorable to growth or survival of pests. Crop rotation is commonly done by many home growers. Crop rotation is just that, a crop is planted in an area of the garden where it has not been grown in for at least one year. Doing this reduces the likelihood that diseases and insects will carry over in the crop residue from one season to the next and effect the current year crop.

 

Proper fertility and selection of varieties of plants that are resistant to diseases are also important parts of an IPM program. Plants that are healthy and vigorous are able to withstand pest pressure better than stressed plants.

 

There are also several types of barriers that can be used to protect a crop. Row covers, which allow for the penetration of sunlight and the movement of air and moisture (but not insects), can be used to protect a crop from migrating insects. Collars made of paper plates, aluminum pans and tin cans can also be placed around the bases of individual plants to protect the upper plant parts from crawling insects.

 

Mechanical controls are also incorporated into an IPM program. This type of control includes simply removing a pest by hand. The removal of over ripe produce will help in preventing the movement of scavenger type insects into the garden and prevent further spread of the disease. This involves taking the diseased plant completely out of the garden area. Sanitation practices such as the removal of fallen leaves and pruning of diseased or dead branches, hand pulling or mowing of weeds can also be an effective way to control many pests.

 

Biological controls are usually naturally occurring. Biological control is the control of pests by other living organisms such as predators, parasites, disease causing organisms or organisms that compete with the pest for food, shelter or space. In practice, biological controls are only commercially available or practical for use against a limited number of pest problems.

 

In most cases, pesticides are used as a backup in an IPM program. Pesticide treatments are made when monitoring shows that preventive measures have not kept pest populations below the threshold level and other pest control methods such as physical or biological controls are not appropriate for use in the situation. If a pest population reaches threshold levels despite preventive measures and other types of controls, chemicals may be the last resort as a rescue treatment. Even chemicals are not a foolproof way of controlling pests. If the pest is too far along in its growth cycle or has built up a resistance to a pesticide, use of chemical may do more harm than good. If a pesticide is needed for a rescue treatment, regardless of what type, be sure to follow the directions on the label. Do not apply at higher rates than directed on the label or use on crops that are not listed on the label. Also be certain to wear protective clothing as required by the label, and observe re-entry and pre-harvest limitations.

 

Call the UNH Cooperative Extension's Family, Home & Garden Education Center 's Info-Line toll-free at 1-877-3984769 for "Practical Solutions to Everyday Questions." Trained volunteers are available to answer your questions Monday through Friday from 9 am to 2 pm .

 

By Rachel Maccini, Coordinator, Family, Home & Garden Education Center UNH Cooperative Extension, Hillsborough County