Drought stress; hail damage

This information was summarized from a June 24 teleconference with Iowa State University extension field specialists in crops.

  • Some areas have been without rainfall for several weeks, and the field crop specialists reported drought-stress symptoms in corn. Other parts of the state have received variable rainfall, including localized heavy rains and hail.
  • Corn is typically at the V8 to V10 growth stage. Potassium deficiency symptoms are showing up in some areas, and affected plants often have shallow root systems because of planting depth, compacted soil, or side-wall compaction. Antracnose leaf blight is being reported and in some areas it is on the same plants that show K deficiency symptoms. A few European corn borers (1/8-inch larvae) were reported. Clarke McGrath (southwestern Iowa) reported small grasshoppers on field edges.
  • Soybean growth stage is mainly V3 to V4. Small numbers of soybean aphids have been reported in Winneshiek, Floyd, and Woodbury counties. Drift calls have continued as Roundup applications are in full swing. Iron chlorosis, soybean cyst nematode, and damping-off in soybean were reported.
  • Second-cut harvest of alfalfa is beginning and in the drier areas the alfalfa is short and not yielding very much. There are a few reports of potato leafhopper, but threshold levels have not been observed. In some areas, the pastures are very dry.
  • Oat crop generally looks good and some are being cut for forage. The wheat is beginning to turn.

This article originally appeared on pages 129-130 of the IC-488(15) -- July 1, 2002 issue.

Updated 06/30/2002 - 1:00pm