Crops generally improving

This information was summarized from a July 20 teleconference with the 14 ISU extension field specialists in crops located statewide.

  • Corn pollination is starting and soybean fields are beginning pod fill in many areas of the state. Unevenness in some cornfields remains but has generally improved with the hot weather and adequate moisture. Potassium deficiency symptoms are showing up on small-rooted, stressed plants. Low, wet areas in some fields show symptoms of nitrogen deficiency.
  • Localized winds caused more damage to crops in some northwest Iowa counties according to Tony Weis and Paul Kassel. Broken-off or blown-over corn was reported. The eastern third of the state has not had rain for 2 to 3 weeks and is showing some moisture stress. Elsewhere, scattered rain (1/4 inch up to 2 inches) was reported.
  • During the last 2 weeks, more farmers have discovered green snap damage in corn from earlier storms. These fields looked okay from the outside rows, but beyond the outside 6 rows, there was from 30 to 90 percent damage to the rest of the field.
  • Gray leaf spot, antracnose, and rust on corn were reported in a few fields, mainly in the southern third of the state.
  • Bacterial blight and brown spot in soybean continue to be common, but damage should be light unless we receive a lot of rainfall according to XB Yang, extension plant pathologist.
  • Bean leaf beetles were reported to be numerous and may cause pod feeding this season, according to Michael White (south central).
  • John Creswell (central) reported soybean cyst nematode symptoms showing up in some soybean fields.
  • Herbicide drift and injury problems are still being reported. These problems have been heightened because of late postemergence application of Roundup on soybean, which has drifted to corn. Several of the field specialists reported problems killing waterhemp, velvetleaf, and lambsquarter in Roundup Ready soybean fields.
  • Virgil Schmitt (east) and Joel DeJong (northwest) reported high numbers of true white grubs in bean fields as well as in corn. Soybean had been planted into some CRP fields.
  • Second cut hay is underway. Potato leafhopper numbers continue to be above threshold in alfalfa.
  • Oats are being harvested statewide with reported yields averaging 25 to 100 bu/acre. In some areas, test weights were very low.

This article originally appeared on page 152 of the IC-480(20) -- July 27, 1998 issue.

Updated 07/26/1998 - 1:00pm