Farmers remember last season’s aphids

Soybean aphids hit late in 2009 and went further south in Indiana than perhaps ever before. What can you expect from soybean aphids this summer?

The Bug Beat panel of Indiana Certified Crop Advisers includes Betsy Bower, agronomist with Ceres Solutions, Terre Haute; Steve Dlugosz, crops consultant with Harvestland Co-op in east-central Indiana; and Bryan Overstreet, Purdue University Extension ag educator in Jasper and Pulaski counties.

How do I know if I should scout for soybean aphids? What’s the likelihood we’ll get a blast of aphids in southern Indiana like in September ’09?

Dlugosz: It’s a good idea to scout your soybeans every year, regardless of conditions. Predicting insect behavior and outbreaks is nearly impossible. Regular monitoring of fields and reading university newsletters is always recommended.

Overstreet: In northern Indiana start scouting in mid-to-late July. In southern Indiana start looking in early August. The number of overwintering aphids was very low. Aphid populations can make a dramatic jump if we have moderate temperatures, low predator numbers and outbreaks in states to the north and west.

Follow the weekly Purdue crop and pest report at

Bower: In most years soybean growers in northern Indiana have more worries about aphids. Overwintering sites are more abundant there. Northern aphid populations move south into Indiana after a cold front, when we get dry, cool north winds.

A year ago southern growers had more R2 to R4 beans growing much later than normal. Aphids left a limited food supply and moved south on winds from the north.

This year about half of Indiana soybean acres north to south were planted by mid-May. A significant number of acres should mature normally. We could see a scenario like last year, but it’s not likely. Still, keep informed about aphids throughout the summer.

This article published in the July, 2010 edition of INDIANA PRAIRIE FARMER.

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