by Greg LaBarge, Fulton County
The every other year appearance of soybean aphid in Ohio on the odd years is still intact even though we have not had treatable population since 2005. Due to various reasons northwest Ohio has been able to miss out on aphids in 2007 and 2009. In 2007 the easter frost hit at a time that took out overwintering population that were already active and it was a low year across the Midwest. For 2009 there were high populations of the aphid in northeastern Ohio and Ontario but did not develop to treatable levels in our area of the state.
Here we are subject to two populations of aphids. One aphid population that can affect our area overwinters in Michigan and Ohio on buckthorn. A second population that can affect us is blown in from the upper Midwest. Since 2011, is an odd year it is likely we will see high populations somewhere in Ohio. We will be scouting as the time comes in mid-summer and you can keep up on developments through this site and the Crop Observation and Recommendation Newsletter at http://agcrops.osu.edu.
The threshold information on soybean aphids has not changed and economic thresholds for this insect are rising populations that reach 250 aphids per plant in a field. Damage threshold where yield loss occurs actually occur are with populations reach 700 per plant. A number of insecticides are labeled for soybean aphid and can be found at http://entomology.osu.edu/ag/images/b545_revised%282%29.pdf on page 37.
There are some new seed genetics out which include resistance to soybean aphid development through a gene identified as Rag1. An article on the pros and cons is found at: http://maumeeag.osu.edu/2011/03/be-cautious-with-soybean-aphid-ressitance-genes-in-ohio/