Keep an eye out on your soybeans for soy bean aphid as they have been found in MI See following message from Dr. Chris DeFonzo. Here is a photo of one -----Original Message----- From: Field Crops AOE [mailto:[log in to unmask]] On Behalf Of Chris DiFonzo Sent: Friday, June 01, 2007 7:57 AM To: [log in to unmask] Subject: SBA found in Michigan Soybean aphids were found on soybean in Michigan yesterday in Berrien County (Mike Staton wins the box of freezie-pops), on the MSU campus, and at the Bean/ Beet Farm in Saginaw. Infestation is less than 1% at each location. Ants on plants really help to key in on colonies. Here is an excerpt from Kathleen Delate's research from Iowa State Univ of an overview of the insect pest. The soybean aphid (Aphis glycines Matsumura) is native to China and Japan, and was a new pest in Iowa in 2000. Aphid numbers were high in the 2001, but in 2002 and 2003, aphids appeared to be less of a problem. This small, yellow aphid has distinct black cornicles ("tailpipes") on the tip of the abdomen and develops colonies on soybean plants as winged and wingless forms. Aphids feed through piercing-sucking mouthparts. The winged form has a shiny black head and thorax with a dark green abdomen and black cornicles. The soybean aphid is the only aphid in North America that will reproduce on soybeans. Therefore, any small colony of aphids found on soybeans must be soybean aphids. The aphid may have up to 18 generations a year, beginning with overwintering eggs on the alternate host of buckthorn trees. These eggs hatch into nymphs and two generations of wingless females develop on buckthorn, before the winged generation flies to soybean fields in the spring. Winged generations appear on soybean plants in the case of crowding from wingless colonies, and in the fall, a winged generation migrates back to buckthorn. These females produce a wingless generation that mates with winged males and lay eggs on the buckthorn trees. Soybean aphid populations build and peak during the period between late seedling stage to blooming stage. Usually in late July, the aphids move from the terminal area of the plant to the undersides, making control more difficult. Honeydew and sooty mold (the excrement of the aphid and the resulting black fungus that grows on it) are apparent in August and September. Stunted plants, reduced pods and seeds may result from aphid feeding. Also, soybean aphids can transmit viruses that cause mottling and distortion of the leaves and a reduced seed set. Discolored seeds may also result from this infection. An economic threshold of 250 aphids per plant if the population is increasing and plants are in the late vegetative or early (R1-R4) reproduction stages has been established (ISU, 2004). This incorporates a seven-day lead-time before the aphid population would be expected to increase to 1,000 aphids per plant, which is the economic injury level and the population size that would be expected to cause economic damage (i.e., yield loss that exceeds the cost of control). There are several natural enemies that help manage the aphid, including lacewings, Asian lady beetles, and entomopathogens (fungi that infect insects, causing a reddish-brown appearance and death). The Leopold Center offers some good biological approaches that can compliment your treatments. Keep in mind when spraying any pesticide (even if organic) it may impact beneficial insects as well as the targeted pest. http://www.leopold.iastate.edu/research/grants/2006/2003-E02_Soybean_Aph id_%5B_Biocontrol_IPM_%5D.pdf <><><><><><><><><><><><><><><><><> Dr. Christina DiFonzo Field Crops Entomology Program Michigan State University East Lansing, MI 48824 Mailing Address: 243 Natural Science Building Office Address: 331 Natural Science Building tel: 517-353-5328 fax: 517-353-4354 <><><><><><><><><><><><><><><><><> If you would like to access previous postings to the Mich-Organic listserv you can copy and paste the following URL into your browser address bar http://list.msu.edu/archives/mich-organic.html