IPM: Nonchemical Pest Control Techniques – Part I
Integrated Pest Management
Integrated pest management is an approach to pest management which employs multiple tactics to:
- prevent pest problems
- suppress pest populations
- minimize the use of pesticides
The types of tactics used include biological, cultural and chemical control methods and the use of pest-resistant plants.
This is a systematic approach to managing pests which uses pesticides sparingly and whose goal is to achieve effective pest control with the least risk to the public health and environment.
Why Practice IPM
The frequent application of pesticides speeds the rate at which insects, pathogens and weeds develop resistance or tolerance to a particular product. When this occurs, it renders the pesticide ineffective. By employing other tactics, such as biological and cultural controls in addition to the use of chemical pesticides, the effective life of a particular product can be extended.
The use of chemical pesticides for the control of pests disrupts the natural environment. Many times, the use of a chemical pesticide will reduce the number of beneficial organisms as well as the pest. With this reduction in beneficial organisms, populations of a pest species have been known to resurge to new highs and with increased vigor due to the reduction of beneficial species previously suppressing the pest population.
Basic Steps of IPM
There are four steps to an integrated pest management program. They are inspection, assessment, action and reinspection.
Inspection
An inspection is required to identify a pest problem as well as any damage caused by a pest.
Assessment
In the assessment phase, the inspector:
- identifies the pest species
- determines the level of pest infestation
- decides what action to implement to correct the situation
For example, if the inspection and the assessment phases reveal that there is a drywood termite infestation with only one board affected. In the assessment phase, one might decide to simply replace the board.
During the assessment phase, the applicator and property owner can decide what population of a pest is tolerable (tolerance threshhold) before a control strategy is implemented. Pests in homes, restaurants, businesses, hospitals and schools are usually tolerated at much lower levels than outdoor locations.
In urban settings, tolerance thresholds are usually based on aesthetics while in rural agricultural settings tolerance thresholds are based on economics. The threshold refers to the population density of a pest at which a treatment method is implemented.
In areas where health concerns exist, the threshold number is commonly zero. This is certainly true for hospitals and food production, preparation and consumption areas.
Action
Action is taken when a tolerance threshold is reached. Correcting a pest problem should always begin with the implementation of preventive measures.
Cultural methods alone are able to solve some pest problems. For example, some weeds thrive on sites that are overwatered, and by decreasing the frequency of irrigation, the weed population can be reduced.
Chemical controls should only be implemented when immediate results are required or when no other strategies will bring a pest population under control. By acting in this manner, there will be less chance of a pest population developing resistance to a particular pesticide.
Cultural Controls. Vegetation management, sanitation, and drainage control methods designed to reduce pest populations are all examples of cultural controls. Cultural controls attempt to provide conditions that are inhospitable for pests. Maintaining a clean environment is a cultural method that goes a long ways in suppressing the numbers of indoor pests.
Structural Modifications. Eliminate or block off areas that harbor pests. Do not allow wood on a structure to touch the soil. Wood in direct contact with the soil is more likely to be attacked by termites and carpenter ants. Prevent damage caused by wood-destroying insects by keeping support timbers off the soil.
Sanitation. Check items for pests before bringing them into your home. Upon returning from a trip, check for bed bugs before bringing luggage inside. Food scraps and refuse needs to be placed in tightly covered trash cans that are frequently emptied and sanitized. Regularly bathe pests and wash items they lay on. Reduce mosquito populations by regularly changing the water in bird baths, pet water bowls, and other outdoor items that hold water. Remove tree stumps and lumber scraps from construction sites; these are an attractive food source for termites. Remove piles of wood from under and around the home. Cleanup pet droppings; they attract flies which can spread bacteria and diseases.
Biological Controls. There are a number of biological control agents available today for the control of pests. Most of these, however, are for outdoor pests. For example, there are beneficial nematodes, fungi, and bacteria that are used to suppress white grub populations and nematodes that attack fire ants.
Physical Barriers. Physically blocking an insect from entering a structure is an effective pest management tool. Place screens on windows, doors and floor drains. Install weatherstripping on windows and doors. Caulk and seal openings in walls and passageways through floors.
Use of Pheromones. Pheromones are chemicals produced by certain insects and other animals that affect the behavior of individuals of the same species. The use of pheromones as a pest management tool has become in managing pests. Sometimes a synthetic pheromone is used to confuse the males of an insect species and prevent mating. Others attract males to a bait station where they consume toxic bait.
Pest-resistant Varieties. By growing plants that are resistant to a pest, there is less need for chemical pesticides. As examples, homeowners can avoid having to treat for brown patch by planting a resistant turfgrass cultivar, and tomato growers can plant cultivars resistant to root knot nematodes.
Chemical Controls. A chemical pesticide is sometimes required to effectively manage a pest. When this occurs, favor insecticides that control the pest while not harming beneficial insects. The goal is to have the chemical control the pest while not harming species that are not pests. The way in which one mixes and applies a pesticide can improve selectivity. Methods by which a broad spectrum pesticide can be more selective include application timing, application technique, dosage level, type of formulation, adjuvants, keeping the pesticide on target. Each of these is addressed in greater detail below.
Application timing – This involves applying a pesticide when the pest is most vulnerable and other species are less vulnerable or not present in the area.
Application techniques – Use good pest application techniques to maximize control of the pest while minimizing pesticide drift onto nontarget areas.
Dosage Level – If effective in controlling the pest, a lower dose of the pesticide might be used to minimize injury to a pest’s natural enemies.
Formulation Type – The type of formulation selected can affect selectivity. For example, granular formulations do not stick to the foliage and will be more effective for soil or aquatic pests. Also, a granular systemic insecticide is absorbed by the roots and transferred throughout the plant. Pests feeding on the plant tissue die and natural enemies and beneficial insects are able to avoid contact with the pesticide.
Adjuvants – One can use attractants to make the pesticide more attractive to the pest; spreaders, stickers and drift control agents to keep the pesticide on target; and surfactants to enhance uptake by target pests.
Keeping the pesticide on target – Minimizing pesticide drift insures sufficient active ingredient reaches the pest and injury to nontarget species is minimized.
Reinspection
After taking actions to control a pest, it is important to inspect the site in the future to determine the level of control achieved and any developing pest problems. This is referred to as reinspection.
There are a good number of products available for monitoring pest populations. This includes light traps, flypaper, spring traps, glue boards, tracking powder, bait stations and pheromone traps. These devices can be used in determining when to treat for a pest. These devices can also be used to learn pest habits, locations and access points which can make control efforts more effective.
Summary
- Accurate pest identification is the first step in the management of a pest.
- Determine the treatment threshold for the pest of concern. Remember, in some situations, such as a hospital, the treatment threshold is zero.
- Determine the control method(s) most appropriate to the situation.
- Apply the control measure(s).
References
Bohmont, B. L. 2007. The standard pesticide users guide. 7th ed. Pearson Prentice-Hall, Upper Saddle River, N. J., Columbus, Ohio.
Renchie, D. L. 2009. Texas pesticide applicator general. Texas AgriLife Extension Service Publ. B-5073.