Good News for Organic Apple Growers: An Insecticide that Kills the Flea Weevil

Weevil damage

Apple Flea Weevil damage

In 2008, the apple flea weevil emerged as a serious pest in Michigan’s organic apple orchards with some growers experiencing >90% crop loss. The organic apple growers were spraying insecticides later in the season to kill major pests like the codling moth and the flea weevil emerged as an early season pest. The weevils feed on developing buds and leaves. Heavy populations cause significant defoliation of leaf tissue resulting in a lacelike pattern which leads to decreased productivity and possible tree death. Research at Michigan State University led to a solution for the organic growers- spray an insecticide…..

“Organic apple growers in the Midwest appear to have a relatively simple solution to their problems with apple flea weevil, which appeared suddenly as a problem in Michigan two years ago and took out 90 percent of the fruit in some orchards.

The best solution, entomologists say, is to spray Entrust (spinosyn) very early in the season, at green tip to pink… The apple flea weevil adult does its most serious damage by feeding on and destroying fruit buds before they have a chance to emerge in the spring.

John Pote, a graduate student at Michigan State University working with Dr. Matt Grieshop and Dr. Anne Nielsen in the organic pest management laboratory, gave the good news to organic growers during a session at the Great Lakes Fruit, Vegetable, and Farm Market Expo in Grand Rapids, Michigan, in December.

Pote noted that the weevil emerged as a problem for organic growers, who normally do not apply insecticides that early in the season, since few insects become active so early.

In conventional apple management programs, the weevil is likely incidentally controlled by insecticide applications made to kill other insects either in April—when overwintering weevils emerge—or in early July—when the summer generation emerges from leaf mines.”

Author: Lehnert, R.
Affiliation: Writer.
Title: Organic control for flea weevil.
Source: Good Fruit Grower. March 15, 2012. Available: