Controlling Insects and Diseases

Many insect and disease pests attacking nut trees can be controlled by spray programs, but the selection of pesticides and timing of sprays must be tailored for the type of tree and the specific pests. Detailed pest control information is beyond the scope of this circular.

Powerful equipment is needed to spray large trees adequately. For the noncommercial grower with a limited number of trees, spraying probably is not practical, except for young trees.

Occasionally, foliage diseases or heavy infestations of insects threaten to defoliate the trees. If the trees are young, spraying is suggested. For aphids, malathion at the rate recommended on the label. For worms and caterpillars, use carbaryl (Sevin) or Bacillus thuringensis at the rate recommended on the label.

For fungus diseases of the foliage, such as pecan scab and walnut anthracnose, use benomyl, maneb, or mancozeb at the rates recommended on the label. Maneb, mancozeb, benomyl, carbaryl, and malathion are compatible and can be mixed together in any combination.

Good cultural and sanitation practices will help reduce losses from some insects and diseases. Keep trees growing with moderate vigor. In the fall or early spring, rake up and burn or haul away old leaves, hulls, unharvested nuts, and dead twigs. During the growing season, pick up and burn or haul away any nuts that fall prematurely--they usually have worms in them.