Soybean Aphid, Aphis glycines

Soybean aphids (Aphis glycines) were collected from Maine soybean fields on September 7, 2004. The USDA confirmed the identification on November 29. This marks the first known find of this insect in the state.

The soybean aphid is native to Asia and was first discovered in the United States in 2000. The current known distribution in the U.S. includes Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, and Wisconsin, with some isolated infestations in Delaware, Kentucky, Maryland, New York, Virginia, and West Virginia. The extent of this distribution suggests the pest may have been present in the U.S. at unobserved levels for two or more years prior to being identified. The highest densities have been observed in Illinois, Michigan, Minnesota, and Wisconsin.

The soybean aphid is considered a major pest of soybeans in China, and soybean crops in the Midwest U.S. have sustained significant injury from this pest. Aphids extract fluids from soybean plants which may result in a reduction in the number of soybean pods. Thus, yield is affected most when soybean aphids attack plants that are flowering or setting pods. Sooty mold typically appears on heavily infested plants. Severely infested plants may be stunted or turn brown and die. The soybean aphid is capable of transmitting several viruses that infect soybean, such as soybean dwarf virus and soybean mosaic virus. Recent laboratory studies showed that soybean aphid can transmit several strains of Potato Virus Y (PVY).

The soybean aphid is small (less than 1/16"), greenish-yellow with two characteristic black cornicles ("tailpipes") on the abdomen. Other species of aphids that feed on legumes are the cotton or melon aphid ( Aphis gossypii ) and the cowpea aphid (Aphis craccivora). The soybean aphid, however, is the only aphid that colonizes on soybeans. The lifecycle of the soybean aphid is complex, and as many as 18 generations are produced in one year. It requires two host plants to complete it's annual lifecycle. The soybean aphid overwinters on buckthorn (Rhamnus spp.) as eggs, and after nymphal development in the spring, winged adults emerge and fly in search of soybean plants. The aphids pass through a series of wingless and winged generations on soybean during the summer with females giving live birth to female offspring. Populations have the potential to increase rapidly as the summer progresses.

The need to treat soybean aphids with an insecticide should be based upon information gathered from regular and thorough scouting procedures. The combination of natural enemies, weather, and aphid biology often causes soybean aphid populations to "crash" within given fields. Intense rainfall may kill many aphids, and high humidity increases the potential for the aphid to be infected with fungal organisms. It is strongly encouraged to assess the situation in each field before making a control decision

For more information visit these sites:

University of Minnesota
National Agricultural Pest Information System (NAPIS)
North Dakota Extension Fact Sheet

If you suspect soybean aphid damage or presence in your soybean crops, please notify the Maine Department of Agriculture (207) 287-3891.

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Soybean Aphid, Aphis glycines

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