Soil Amendments, Biocontrols Help Potatoes Thrive

Soil Amendments, Biocontrols Help Potatoes Thrive

Healthy soil and a dynamic ecosystem allow potato plants to compete better against pests and could provide growers with more consistent yields, SARE-sponsored research in Maine suggests. Use of amendments such as manure and potato-based compost improve soil structure and enable fields to retain more moisture, the results show. In droughty conditions, amended plots averaged 28 percent higher yields in 1994 and 9 percent more in 1995 compared with conventionally managed potato plots. Although use of the purchased amendments added $270 per acre in costs, yield increases and adequate crop prices should enable potato farmers to cover expenses and boost overall profits. Growers could trim costs by reducing use of commercial fertilizers and by composting their own potato culls, other studies show. Scientists in the SARE-funded project also are developing environmentally safe ways to manage Colorado potato beetle, a common and sometimes devastating pest increasingly resistant to insecticides. Introducing beneficial stinkbugs and two microbial pest controls--Beauveria bassiana and Bacillus thuringiensis--reduced emergence of beetle adults in potato plots by an average of 65 percent. The beneficials spread slowly, and two of them--the stinkbug and B. bassiana--are not commercially available yet. But they could prove cost-effective in some areas eventually. Combined use of the beneficials gives a longer pest-control period than is possible with conventional insecticides. (Northeast Region projects LNE93-36 and ANE93-18)

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