Pest Control Using Integrated Pest Management (IPM)

The increasing concern for our environment and for human health has led commercial growers and farmers as well as gardeners to consider safer ways of dealing with the problems of insects, diseases and weeds. Although a number of the more toxic pesticides have been removed from general usage, there has been a search for other ways of controlling pests than by only spraying chemicals on crops and gardens.

A number of years ago a system was developed to consider preferable alternative ways to deal with pests. This system has been termed Integrated Pest Management (IPM). Although the use of pesticides has not been abandoned it has been relegated to the lesser of other choices.

IPM includes a number of steps to follow and evaluate before taking action to control the pest. These are as follows:

Plan Ahead
Have you had this problem before? What time of year did it occur? How long did it last? What effect did it have on the yield or aesthetic value of the crop? Have other growers/gardeners had the same problem, and if so how did they deal with it? What area has been affected - is it an isolated or a general problem? And finally, how are you going to approach and solve the problem?

Set a Threshold for Action
Do you believe that the only good bug is a dead bug? If there are only a few bugs present doing minimal damage over a period of only a week or two it may not be necessary to try to get rid of them. Most plants can tolerate some damage without affecting the yield. When considering the aesthetic value of a plant, does every leaf and petal need to be perfect? At what point do you need to take action? The answer to these questions will vary from person to person.

Monitoring
The earlier one detects the presence of insects, diseases and weeds the better chance there is of controlling them. Rely on past history of what goes on in your yard in particular times of the year and consider the influence of weather patterns - wet vs dry, cold vs hot as well as the earliness or lateness of the season. For example, from past experience I know that usually in late May or early June the foliage of my perennial Columbine plants will most likely be attacked by Columbine sawfly larvae. So, at that time of year I start to watch for them, so I can pick them off the leaves. The severity of their attack, however, will depend on the weather. Some years they reappear in late summer for a second attack and some years they don't.

Proper Identification of the Problem
What you are going to do to solve the problem will depend on proper identification of the pest. Once this has happened you will need to know its biology and life cycle so you can determine the most opportune time to take action for control. One year I sprayed the "caterpillars" devouring the leaves on a Mountain Ash tree with a compound containing the biological Bacillus thuringiensis (B.t.), not realizing that the worms were actually sawfly larvae, which are not controlled by that particular insecticide.

Taking Action
There are several choices that may be taken once you have identified the problem pest and want to take action to control it. At this point you might want to decide which options will have the least and most impact on the environment, your family and your pets. This is where IPM is completely your choice.

Biological Control - Identify and apply natural beneficial organisms that are the enemies of the pest. Make sure that the environmental situation is favorable for these organisms so that they may flourish.

Cultural Control - By keeping your plants at the peak of health they will be more resistant to disease and insects. Some cultivars of plants are naturally more resistant to insects and disease than others. Mulching will help to control weed growth. Rotation of crops can help avoid the same disease problem the next year.

Exclusion - Physical removal of the pest or plant material that has already been affected will help cut down on the problem. Covering fruit plants with screen or mesh will keep out bird pests. Screening your windows and caulking the cracks around doors and windows will help keep out invading household insects.

Chemical Control - If other strategies have not been deemed effective, the use of pesticides may be necessary. Make sure that you read the label to determine if the target plant is listed on it. Try for a lower toxicity formula and make sure to follow the mixing directions. Labels are legal documents. Spray or apply the pesticide only to the affected plant material. Try to keep human exposure to a minimum.


The final step in IPM is to pay attention to what worked and what didn't. It will help to take careful notes throughout the process. Note the time of year the problem arose, what kind of environmental conditions prevailed. What part of the plant was being affected? Where in the yard or in the garden did the problem occur? And then, what did you do to address the problem and was it effective? Keep in mind that if the same problem occurs next year you may have to use different strategies. IPM is all about being flexible.

Roger Hintze has BS and MS degrees in Ornamental Horticulture from the University of Minnesota and has been employed by J R Johnson Supply for 40 years. J.R. Johnson Supply headquartered in Roseville, Minnesota is a horticulture supplier and has over 30,000 items available in its on-line store. Specialties include soil media, containers, pesticides, fertilizers, irrigation equipment, nursery supplies, greenhouse supplies, organic growing supplies, generic chemicals, and landscape or retail garden center supplies. Jr Johnson is now selling products for the hobby grower, such as Compost Tea Brewer and Raised Garden Beds.