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ARS Home » Northeast Area » Orono, Maine » New England Plant, Soil and Water Research Laboratory » Research » Publications at this Location » Publication #224447

Title: Reduced Pest Insect Densities Following Compost Application in Organic and Conventional Systems

item Larkin, Robert - Bob

Submitted to: Northeast Potato Technology Forum Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2008
Publication Date: 3/13/2008
Citation: Gross, S., Alyokhin, A., Larkin, R.P., Erich, S., Tavantzis, S. 2008. Reduced Pest Insect Densities Following Compost Application in Organic and Conventional Systems. Northeast Potato Technology Forum Abstracts. CD-ROM.

Interpretive Summary:

Technical Abstract: The effects of compost and biological amendments on soil fertility, soil microbial communities, soil-borne diseases, insect pests and potato yield quality and quantity were assessed at two farm sites in Northern Maine in 2007. The two sites were: Aroostook Farm (AF), a research farm using conventional production practices, and Wood Prairie Farm (WP), a commercial organic farm. Compost amendments consisted of a conifer-based material containing lignocellulosic substrates. The biocontrol organisms were a hypovirulent strain of Rhizoctonia solani, a bacterium Bacillus subtilis, and Trichoderma virens, a fungal parasite. These organisms have been used to reduce disease and increase yield in crops. Thirty plants were selected at random in each plot, at weekly intervals, and visually examined for the presence of pest insects and their natural enemies. Potato plants grown in soils amended with compost supported 14-21% fewer Colorado potato beetle larvae, up to 90% fewer green peach aphids, 40% fewer buckthorn aphids, and 58% fewer flea beetles when compared to plants grown without compost. In contrast, compost-grown plants had 15% more Colorado potato beetle adults and 20% more egg masses than control plants, probably because early emergence and more vigorous plant stand early in the season encouraged their colonization by overwintered adults. The three tested biocontrol organisms did not produce consistent results in terms of suppressing insect pest populations in the 2007 field season. Our results indicate that compost is effective in reducing pest insect populations in potato.