Soybean Aphids Remain Low in WI, Continue Scouting to Detect Change

Eileen Cullen, Extension Entomologist, UW Entomology Department

Soybean aphid reports from UW Extension county agents, crop consultants, industry reports, and our UW Entomology field studies remain below threshold for the most part as of Friday July 21^st.  However, Greg Andrews, UW-Extension Pierce County Agriculture Agent (northwest WI) reported a soybean field averaging 250-500 aphids per plant.  A treatment recommendation was made for the field; Greg’s diagnosis as of July 19^th had reached threshold of 250 aphids per plant over 80% of the field. Soybean aphid populations have reached treatable levels in other areas of the north central region as reported by Ian McRae, NW Research and Outreach Center, Dept. of Entomology University of MN, Crookston, MN; and Phil Glogoza, Regional Extension Educator, Univ. of Minn. Extension Service in Moorehead, MN reporting averages from 150 per plant to the thousands.

In Wisconsin, we are picking up winged soybean aphids in our suction trap network and in our Entomology research plots. Similar observations of winged aphids have been relayed to me at field days the past two weeks by consultants statewide. This presents the potential for dispersal flights and colonization of new field sites. Continue to scout soybean fields for soybean aphids. I’ll provide Wisconsin reports from our trials, and reports received by UW Extension county faculty, producers and agricultural professionals if/as numbers increase or remain at currently low levels (as of July 21^st).