Managing Pests With Healthy Soils

Healthier soils produce crops that are less damaged by pests. Some soil-management practices boost plant-defense mechanisms, making plants more resistant and/or less attractive to pests. Other practices — or the favorable conditions they produce — restrict the severity of pest damage by decreasing pest numbers or building beneficials. Using multiple tactics

— rather than one major tactic like a single pesticide — lessens pest damage through a third strategy: it diminishes the odds that a pest will adapt to the ecological pest management measures.

Practices that promote soil health constitute one of the fundamental pillars of ecological pest management. When stress is alleviated, a plant can better express its inherent abilities

Encourage beneficial to resist pests (Figure 2). Eœbgkd pest

T I P organisms by using management emphasizes preventative crop rotations, cover crops, strategies that enhance the "immunity"

animal manures and œinpœte of the agroecosystem. Farmers should be to supp|y them with additiona| cautious of using reactive management ' practices that may hinder the crop's im munity. Healthier soils also harbor more diverse and active populations of the soil organisms that compete with, antagonize and ultimately curb soil-borne pests. Some of those organisms

— such as springtails — serve as alternate food for beneficials when pests are scarce, thus maintaining viable populations of beneficials in the field. You can favor beneficial organisms by using crop rotations, cover crops, animal manures and composts to supply them with additional food.

Aref Abdul-Eaki, IJSDA ARS

Aref Abdul-Eaki, IJSDA ARS

Potato plants grown in rye residue in plots run by USDA-ARS's insect Biocontrol Lab (top) fare better than those grown using a system without cover crops (below).

In southern Georgia, cotton and peanut growers who planted rotation crops and annual high-residue winter cover crops, then virtually eliminated tillage, no longer have problems with thrips, bollworms, budworms, aphids, fall armyworms, beet armyworms and white flies. The farmers report that the insect pests declined after three years of rotations and cover crops. They now pay $50-$100 less per acre for more environmentally benign insect control materials such as Bacillus thuringiensis (Bt), pyrethroids and/or insect growth regulators.

In their no-till research plots with cover crops and long rotations, University of Georgia scientists haven't needed fungicides for nine years in peanuts, insecticides for 11 years in cotton, and insecticides, nematicides or fungicides for 17 years in vegetables. They also are helping growers of cucumbers, squash, peppers, eggplant, cabbage peanuts, soybeans and cotton reduce their pesticide applications to two or fewer while harvesting profitable crops. This system is described in greater detail in Managing Cover Crops Profitably, 2nd Edition (Resources, p. 104).

Aref Abdul-Baki, USDA ARS

Aref Abdul-Baki, USDA ARS

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