By Matt Reese
To date, farmers have been fortunate that entomologists had the soybean aphid pretty well figured out in Ohio.
“Soybean aphids have been a pest in Ohio since 2000 or 2001 and we seem to have outbreaks every other year. In odd numbered years we tend to have outbreaks,” said Andy Michel, assistant professor at OARDC and Ohio State University Extension with a specialty in soybean insect management. “For the past 10 years we were fairly comfortable with the every other year pattern. In Iowa and the midsection of the country, there seemed to be a couple of years where the population cycle was out of whack. But that didn’t happen in Ohio and it has gone in the every other year pattern as we had predicted.”
But, like just about everything in nature, just when it gets figured out something can change.
“This year something odd happened. We had a fair soybean aphid population in Ohio, it was scattered, but we considered it a relatively high aphid population year in 2011,” he said. “It seems like the two-year cycle is holding, but it might not hold for next year.”
Entomologists have typically been able to keep pretty close tabs on the soybean aphid population by monitoring their autumn activities.
“When soybeans start to senesce, the soybean aphids move from soybeans to buckthorn to mate and lay eggs. We can track this migration, so the amount of aphids we see on buckthorn indicates the population for the next year. If we see a large population it would indicate that the following year we would see a large population on the soybeans,” Michel said. “After outbreak years, we do not typically see a large migration to buckthorn or eggs on buckthorn, but this past year we have seen a fair amount of aphid migration to buckthorn. We’ve seen a fair amount of eggs present on the buckthorn as well. This is atypical of what we see after high aphid population years. This could indicate that we may see significant aphid populations in an even numbered year in 2012, which would be the first time that happened in the 10 years we have been studying them.”
For more about Ohio’s potential pest problems in 2012, see the Mid-November issue of Ohio’s Country Journal.