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Invasion of the Soybean Aphids September 23, 2009

Filed under: Uncategorized — Jen @ 9:00 am

For those of you who have heard Ben or me complain about the terrible swarms of bugs that have been bugging us, here is an article from the News Gazette about the Soybean Aphid Invasion.

Bothersome soybean aphids here to stay for now

By Christine Des Garennes
Tuesday, September 22, 2009 2:25 AM CDT

First, they’re not gnats.

Second, you can try bug spray to get rid of them, but there’s plenty more to replace the ones you killed.

Third, they may be here awhile.

You know those tiny, flitting, pesky insects of late, the ones that keep flying in your eyes and nostrils while you’re riding your bike, the ones that keep landing in your drink, that have covered your deck chairs, your child’s sand toys, not to mention your car’s windshield?

Yes, those bugs.

“We are being invaded by soybean aphids,” said Curt Hill, a principal research specialist in crop sciences at the University of Illinois.

A mild summer helped play a part in the large population of soybean aphids this year.

The bugs, which began their lives on buckthorn and spent the summer sucking sap from area soybean plants, are now thinking about their progeny.

The most talked-about (or rather, cursed-about) bug of the month, soybean aphids are moving out of the fields, and they’re looking to lay some eggs.

They need to overwinter in buckthorn, an invasive shrub or small tree, to do so. A few million or so have found a big patch of it outside a greenhouse near the National Soybean Research Center on campus.

For all of you new to town, “it’s not always this bad,” Hill said.

Like other crops, soybeans were planted late this year due to the spring rains. And the summer weather was not hot and muggy. Turns out temperatures were ideal for growing populations of the little bugs.

The soybean aphid goes through several different stages, according to Hill. Once the eggs hatch on buckthorn, a few generations will remain on the shrub. Eventually they make their way to soybeans. The summer stage of the aphid is actually an asexual stage. But they can reproduce asexually. Plus, when born, the aphid actually is pregnant.

Yes, pregnant. Making more aphids is something they’re quite good at doing.

“Under ideal conditions … researchers have found aphids can double their population size in 1.2 days. Populations can really explode,” Hill said. The optimal temperature is about 80 degrees, he said.

And the aphids’ predators, the multi-colored Asian ladybeetle, haven’t kept up pace.

The aphids usually stay in the fields until the day length starts to decline, and eventually they change to another stage called gynoparae, and that’s when they start migrating away from the soybeans and go out in search of buckthorn.

And that is the current stage of most of the aphids that are finding their way into our clothes, our hair and our cold beverages.

You can expect to keep swatting at them, too.

“They could be around for quite a while; there’s still a lot of green soybeans out there,” Hill said.

Until there are some hard frosts or the soybean crop is completely harvested, they’ll still be flitting around, he reported.


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