Answer: Lesser peach tree borers are difficult to control completely without some spraying, says Allen Otterbacher, pomologist at the University of Illinois in UrbanA. The larvae overwinter on the bark of trees and emerge as adults to lay eggs in tree crotches and wound sites in May and June in Illinois. The larvae hatch in 10 days and bore into the tree trunk. Once inside the bark, they are difficult to eliminate other than by taking a thin wire and pushing it into the holes to squish the larvae, explains Otterbacher. The key to control is preventing the adult borer from laying eggs. Pheromone traps, placed on per tree, will help you monitor the adult populations as an indication of when to apply an insecticide. Combining the traps with a spray of Sevin or rotenone on the lower branches and trunk in mid June, mid July and mid August should kill most adult borers before they lay eggs, says Otterbacher. Pruning to keep branch angles between 60_ to 90_ also prevents borer larvae from easily entering the bark through the tree crotches, he notes. Protecting the tree trunk from June to September with a layer of duct tape, sticky side out, or a heavy coat of outdoor white latex paint will sometimes prevent the adult borers from laying eggs on the bark, he adds.
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