New problems emerge in soybeans

Two soybean pests, one a mysterious disease, the other an aphid, bear watching in the coming year. They're not yet at the point of becoming widespread, but they are new to the upper Southeast, making their debut last year.

The mysterious first: There it was this past season in the upper Southeast. Alongside otherwise healthy soybean plants, just as tall, were soybeans stripped bare of leaves, victims of Sudden Death Syndrome.

Long a problem in the Mid-South, SDS was found for the first time in North Carolina last season, says Jim Dunphy, North Carolina State University soybean specialist, speaking at the recent joint small grains, wheat and soybean conference in North Carolina.

SDS shows up in a hurry. Affected plants are often as big as other plants. It usually occurs in high-yield fields, on better soils — and in some cases in fields that have problems with cyst nematodes.

“SDS is hard to diagnose in the field,” Dunphy says. “SDS survives in the soil long enough that rotation is not very effective against it.” Resistant varieties are available, but at this point, Dunphy isn't making a recommendation on varieties.

Along with SDS, the soybean aphid is another pest new to the upper Southeast.

It first appeared in the Midwest in 2000. Producers in southern Virginia saw the soybean aphid for the first time in 2001. A native of Japan and China, some soybean aphids have wings, while others are wingless.

In the Midwest, soybean aphids cause problems early in the season.

In Virginia last season, the soybean aphid appeared late in the season, but did not cause much yield damage.

“Both SDS and the soybean aphid are problems at this stage I wouldn't do anything to change practices,” Dunphy says.

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