Primary symptoms

Soil pests are generally a problem in rainfed wheat. They primarily cause root damage leading to weakened or stunted plants . Physical damage to the roots is a clear indication of damage. Because of the effect of these insects, along with nematodes, on plant roots, they can cause problems of drought stress or lodging.

White grubs attack roots

Summary

Soil pests such as termites, ants, mole and field crickets, ground beetles, white grubs, wireworms, root aphids and root bugs usually pose a major problem only in dryland agriculture. Under irrigation, crop growth is faster and more regular and so the crop has greater capacity to grow through any damage by pests. Tillage also protects the crop from soil pests. It exposes soil pests to dessication and disrupts their food supplies while regular flooding disturbs their habitat. Removal or incorporation of crop residues further limits habitat and food resources. Under minimum tillage or direct drill practices some of the soil pests may build up over the years.

What to do about soil pests

If problems do arise, try the following after the pest has been identified

• Crop rotation: Use a break crop (or fallow) that the pest does not feed on.
• Cultivation: Cultivate to remove or completely incorporate residues, and remove weeds.
• Crop nutrition: Improve crop nutrition and optimise flood irrigation to keep the crop growing quickly to outgrow the pest.
• Planting date: Time planting to be out of phase with the growth cycle of the pest.