Accumulated Base: 50° F Degree Days May 1 through July 17, 2005. Top: Accumulated degree days. Bottom: (departure from average).
Continued warm weather has pushed degree-day accumulations slightly above seasonal averages this week. Rains on Sunday night (July 17) were welcome, but unfortunately missed southeastern and east central Iowa--the driest parts of the state.
Speaking of dry conditions, spider mites on soybean have appeared in eastern Iowa. If you consider any insecticide treatments for soybean aphid, bean leaf beetle, grasshoppers, or for that matter any other insect pest, remember that most pyrethroid products pose a mite flare-up risk. See the discussion in the soybean aphid and two-spotted spider mite articles, pages 145--147.
Also, western bean cutworm egg masses have been found in Buchanan and Pottawattamie counties, among others. The Western Bean Cutworm Monitoring website has some management suggestions.
This article originally appeared on page 152 of the IC-494(19) -- July 18, 2005 issue.