Title: Lecture 22 – Insect Management

Speaker: Teresa Koenig

Created by: Teresa Koenig, Kim Kidwell

online.wsu.edu

Insect Management

IV. Pest Control A. Principles involved in establishing an effective control program: 1. The pest must be accurately identified.

2. Population size must be accurately estimated to determine the potential crop damage that would occur if left uncontrolled.

3. An effective method, both economically and environmentally, must be implemented.

B. Integrated Pest Management (IPM): Uses a complete system of pest control to address the problem.

1. Considerations: a. Population dynamics of the pest. b. Its biology and life cycle. c. The effects of cultural practices and weather on the reproduction and growth of the pest.

2. Objective: Use the control methods that control the pest, or reduce the population below economic damage levels, while minimizing detrimental effects on the environment.

3. Action (control, economic) threshold: The pest level at which control measures are warranted.

When the economic damage to the crop exceeds the cost of control, the use of a control method is justified.

What are some things you might

consider if you were setting threshold

limits of insect damage on:

• lettuce leaves,

•potato tubers,

•stems of asparagus,

•pepper fruit,

•pansy flowers.

C. Pest Control Methods 1. Genetics: Plant breeders continually strive to develop varieties that are resistant to, or tolerant of, pest feeding.

a. Advantages: No chemicals are required; genetic resistances tends to last longer.

b. The host plant does not suffer economic damage if infested with the pest.

2. Cultural Control: Changing the cropping sequence, tillage, cultivation, weed control, etc. to reduce the infestation level of the pest.

a. Crop rotations Effectively reduce pest population levels whereas continuous cropping increases pest levels.

b. Changing seeding date Planting earlier or later is often used to avoid pest infestation.

c. Plowing, disking or burning: Used sparingly

d. Control weeds Reduces the chance of over- wintering and limits feeding areas.

3. Biological Control: The use of other living organisms to reduce pest populations.

a. Parasitic insects Example: Ladybug beetles feed on aphids

Photo courtesy of USDA ARS

b. Pest-specific diseases Example: Cotton boll weevil is destroyed by a bacteria called Bacillus thuringensis (Bt). This gene has been transferred into other crop plants via genetic engineering.

http://en.wikipedia.org/wiki/Cotton_boll_weevil

c. Hormones or pheromones (sex hormones) Example: Pheromones are used to attract males to traps so they cannot mate.

4. Chemical Control: The use of pesticides (insecticides, miticides and nematicides) to control insects, mites and nematodes.

a. This is the most costly control measure and has the greatest effect on the environment.

b. Classified by their mode of action

1.Contact poisons:

Kill by direct body penetration or through entering breathing pores. Controls piercing- sucking insects and mites since they do not ingest plant material.

2. Stomach poisons: Kill when the insecticide reaches the stomach with ingested material. Used to control chewing insects.

3. Systemic poisons:

Absorbed by the plant then ingested by the insect during feeding. Can control any type of pest that they can kill. Problem: Chemical may accumulate in plant parts harvested for food.