Soybean aphids piling up in a spider web

Soybean aphids piling up in a spider web

It’s been snowing aphids the past few days here in Champaign-Urbana. Trillions of them are drifting across town, settling out on our garden, getting caught in our hair. I’ve never seen anything like it.

I recently learned that this sternorrhynchan storm is composed of soybean aphids (Aphis glycines). That would explain all the aphid biomass. Illinois is a major producer of soy, and there’s no shortage of soy fields around here. Sensing the end of summer, the aphids are moving en masse to their winter host, buckthorn.

AphisGlycines2

Soy has traditionally been easy to grow in North America as it lacked any major insect pests. Until about 10 years ago, that is. That’s when the first soybean aphids, an Asian species, showed up in Wisconsin. Given the sheer numbers of these insects, I can’t imagine this bodes well for soy yields this year.

AphisGlycines3

***update (9/21): I’ve added an Aphid FAQ