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:

Stopping the Nematode Threat to Potatoes with Fumigation


PCN Damage (right)


PCN cyst hatching

Cyst nematodes are a huge potential threat to potato production in the US. Nematodes are microscopic unsegmented worms. Roots of infected plants contain minute, white bodies of females. When a female dies, its cuticle forms a protective cyst containing 200 to 500 eggs. Cysts containing viable eggs can persist in the soil for up to 20 years. When potatoes are planted, root exudates stimulate juvenile nematodes to emerge from eggs. The juveniles locate and enter potato roots. They cut through cell walls and feed. Infection with nematodes reduces root biomass, which can lead to stunting of plants, yellowing and wilting of foliage and small tubers. Heavy infestations often results in total crop loss. Potato cyst nematodes are widespread in many countries, but only two localized infestations have occurred in the US. The latest infestation, found in Idaho in 2006, has led to a strict treatment program with fumigants.

“Two species of potato cyst nematode are found in the United States: Globodera pallida, the pale cyst nematode (PCN), was first found in Idaho in 2006, whereas the golden nematode, G. rostochiensis (GN), was first found in New York in 1941. Both species are regulated under a Federal Domestic Quarantine Order (USDA-APHIS) and parallel State Rules (Idaho State Dept. of Agriculture, New York State Dept. of Agriculture), and eradication effects are underway.

While some resistance to PCN is present in potato varieties grown in Europe and elsewhere in the U.S., there is no resistance in most of Idaho’s signature russet varieties.

The presence of G. pallida in Idaho has been viewed with alarm by other states and countries that import Idaho potatoes and other farm products. After the initial Idaho PCN detection in 2006, markets for Idaho fresh potato products and nursery stock were lost for Canada, Mexico, and Korea. Japan temporarily closed the market for all U.S. potatoes, and continues to disallow Idaho shipments. Consequently, eradication of PCN is a top priority for the Idaho potato industry, including the Idaho Potato Commission, the Idaho State Department of Agriculture, and USDA-APHIS. Millions of dollars have been spent in Idaho in eradication efforts. A critical component of this work has been treatment of infested fields with the fumigant methyl bromide (MeBr), which has been ongoing since the spring of 2007. Lab tests conducted after each treatment indicate a 95% viability reduction after one year’s fumigation, and over 99% viability reduction after successive treatments.”

Author: Dandurand, L. M.
Affiliation: University of Idaho, Moscow
Title: Novel Eradication Strategies for Pale Cyst Nematode
Source: Potato Progress. September 16, 2013. Volume XIII, Number 10.

U.S. Crop Losses Significantly Reduced with Pesticides

Prior to the widespread adoption of synthetic chemical pesticides in U.S. crop production in the 1950s, many pests were destroying a significant portion of the food supply. Following the widespread adoption of pesticide use, the losses due to pests were reduced significantly. This point was made in an economic analysis by University of Maryland researchers…..

“… models indicate crop damage on the order of 15% during the early 1950s and crop damage falling steadily as pesticide use spread, reaching 11% in the mid 1960s, 6% in the mid 1970s, and stabilizing at about 3% from 1979 through the ensuing decade.”

Authors: Robert G. Chambers and Erik Lichtenberg
Affiliation: University of Maryland Department of Agriculture and Resource Economics
Title: Simple econometrics of pesticide productivity.
Publication: American Journal of Agricultural Economics. 1994. 76:407-417.