Soybean aphids starting the season early in Ohio
Almost 2 months ago, crop specialists in Ohio predicted 2009 to be a big year for soybean aphids in the eastern Corn Belt.
"The main criteria we are basing this on are the fall collections of winged aphids in suction traps in neighboring states to our west and north. In a number of these traps, fall collections were high," Ohio State University Extension entomologist Ron Hammond said in early April. "These numbers had followed a summer when suction trap collections in these same sites were very low. This scenario, low summer captures followed by high fall collections, has usually been the determining factor when making the aphid prediction for Ohio.
"We could be wrong in our prediction, but we have called it correctly for the past six out of seven years," Hammond added. "On the plus side, if we are wrong, at least it will be to the grower's benefit."
Hammond wasn't wrong. This week, he and fellow OSU Extension specialists confirmed aphid numbers that indicate the pest overwintered.
"We were out in the fields in northwest Ohio last week and found a few, so that meant that aphids had survived overwintering," Hammond says in a university report on Wednesday. "But just this week, we scouted early planted fields...and to our surprise, we were finding aphids, and not just one or two. Many plants had 30-50 aphids on them; some had over 100 aphids.
"Based on this assessment, the soybean aphid has the potential to be a huge economic problem we expect in these odd-numbered years," he adds.
Aphids are typically heavier in odd-numbered years, Hammond says, but this year's signs of early infestation aren't just because of the calendar. Rain-delayed planting dates may have a lot to do with the populations detected thus far.
"It's not a normal situation for these early plants to have these kinds of numbers in Ohio, but when the soybean aphid began its initial movement after overwintering, early planted fields were the only soybean plants available. So we are seeing heavier infestations than normal," Hammond says. "In a normal year with more soybean plants in the ground, the aphids might have spread themselves across fields and the insects wouldn't have been so concentrated or as high in one area."
If you're still working to get your soybean crop planted, you are likely in decent shape so far. But, if you were lucky enough to get your crop in the ground without any rain delays, you may want to start watching for aphid pressures already.
"Right now, we think the chances of growers finding aphids on most soybeans are slim because of the late planting. However, if they have early planted fields, it would be worthwhile to scout. We have not been finding aphids on fields treated with Cruiser," Hammond says. "We continue to recommend taking an Integrated Pest Management (IPM) approach to aphid management. While seed treatments will control early season aphid populations, they will not have any impact in mid-summer when aphids arrive in large numbers."