Tuesday, April 24, 2012

2011 Corn/Soybean Yellow Books now available

Each year, the ISU Entomology Department produces a few Yellow Books that evaluate insecticide efficacy and PIPs (plant-incorporated protectants). My lab produces one for soybean insects, but mainly focuses on soybean aphid. Aaron Gassmann produces one for corn insects, with the majority of the report on corn rootworm.

Both are available (FREE!) as a pdf on our departmental website.

View the 2011 Corn Pests Yellow Book.

View the 2011 Soybean Pests Yellow Book.

Monday, April 23, 2012

Are you seeing painted lady butterflies?

Last week, I had several people ask me about painted lady butterflies in Iowa. They reported seeing high numbers and were wondering if this was an insect we should keep an eye on this summer. The last time I remember seeing high populations was in 2003 (while I was a grad student up in St. Paul, MN). Of course the adults are beautiful butterflies, but farmers care about the larvae (called thistle caterpillars) that are defoliators in soybean.

Thistle caterpillars are unique-looking defoliators. They have dark bodies with yellow strips, and short spines. Photo by Marlin E. Rice.

Thistle caterpillars do not overwinter in Iowa and must migrate here every year. The first generation larvae can cause the most injury during V3-V4. The last two instars eat about 97% of the soybean tissue consumed.