Yet another week of near normal temperatures has kept Iowa near the long-term average in growing season heat accumulation. Iowa crops are now growing well in most of Iowa, with corn between V5 and V10 and soybean mostly V3 to V6, with a few fields in southern Iowa beginning bloom (R1).
Pests of field crops present now include some very early bacterial blight and brown spot on soybean. Also, European corn borer adults are flying, with some egg masses being reported. Thistle caterpillars have shown up statewide on soybeans, but only rarely do they reach economically significant populations to warrant treatment. Another week has passed with marginal soybean rust activity in the Gulf Coast states, which continues to be good news for Iowa soybean growers.
Accumulated Base: 50° F Degree Days May 1 through June 19, 2005
This article originally appeared on page 128 of the IC-494(15) -- June 20, 2005 issue.