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Soybeans
Volume 59 Number 7 Date 06/12/2014 SOYBEAN APHID - This insect has begun to colonize soybeans in southern Wisconsin. Alates (winged aphids) and nymphs were detected on 1-3% of the plants in six of 13 fields surveyed in Crawford, Richland and Sauk counties from June 5-11. Densities were extremely low at 1-6 aphids per infested plant. Forty-six additional fields examined in Calumet, Dane, Green, Fond du Lac, Jefferson, Juneau, Kenosha, Manitowoc, Racine, Rock, Sheboygan, Walworth and Winnebago counties had no detectable aphid population. According to a May survey by research entomologists Drs. Dave Hogg and Dave Voegtlin, aphids were found in only two of seven locations sampled in Illinois, Indiana, Iowa, Michigan, Ohio, and Wisconsin and densities on common buckthorn (the primary host) were lower than in the previous two years. These results indicate potentially lower initial soybean aphid populations for the Midwest this season. BEAN LEAF BEETLE - Surveys conducted across the southern half of the state found light defoliation in 14 of 52 (27%) soybean fields. Less than 5% of the plants were affected and beetle counts were very low, ranging no higher than 1-2 per 25 feet of row. Treatment for this pest during the vegetative stages should be considered only if defoliation levels exceed 40% or if populations of 39 or more beetles per foot of row are observed. Economic damage directly attributable to this pest has never been documented in Wisconsin soybeans. -- Krista Hamilton, DATCP Entomologist 
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