Seed Money - Aphid alert enriches potato producers in northern Minnesota

Crookston, Minn. — Keeping a close watch on a costly potato pest has saved growers up to $6 million so far, says Duane Maatz of the Northern Plains Potato Growers.

Basic changes in field practices are all it takes to decrease insecticide use, increase yields and save money, Maatz says. Virtually all seed potato producers in the Red River Valley region have adopted changes recommended by an AURI-funded aphid study.

As part of AURI’s Pesticide Reductions Options, a $200,000-per-year research and demonstration program, the “Aphid Alert” program for potato growers is “very valuable,” Maatz says. “It’s one of the best seed growers can use to minimize exposure to virus infection.”

Researchers found that green peach aphids, which carry a virus to potato leaves, usually land on the perimeter of potato fields. By monitoring aphids caught in traps, growers can determine the right time to spray insecticide.

Early results show that by targeting insecticides to specific areas and times, growers can reduce the amount and frequency of pesticide applications. An added benefit is that aphids’ natural enemies aren’t harmed, so subsequent aphid outbreaks can be more naturally contained.

Studies in 1999 and 2000 indicated first applications could be reduced by as much as 85 percent. Although severe weather hampered aphid research in 2001, new PRO trials are underway for 2002.

Once preliminary results were out, seed producers adopted the new methods almost immediately, Maatz says, saving the approximately 100 producers about $6 million over the past two years in insecticide and application costs. Producers pay about $23 per acre for aphid pesticide application.

If a seed crop is infected with potato virus, Maatz says the resulting crops are less valuable, especially for products such as french fries. Affected potatoes fry up darker and are less desirable to the food industry. The region’s growers have North America’s highest standards for seed potatoes; only a half percent show signs of viral infection, Maatz says.

More seed potatoes passing winter certification trials in 1999 and 2000 translated into $920,000 additional income for producers, reports Maatz and project investigators Edward Radcliffe, David Ragsdale and Ian MacRae.

Early recommendations also “show potato farmers can do basic field production practices, like changes in planting dates and changes in the kill dates of (potato) vines, to save an awful lot of money on insecticides,” Maatz said. “All the seed growers are following (the recommendations). They’re very much in tune with what’s going on in their fields.”