Yellow corn; soybean damping-off

This information was summarized from a June 8 teleconference with ISU extension field specialists in crops.

  • Corn and soybean development has been slowed by cool, wet weather and in general little growth has occurred during the past week.
  • Hail damage from storms on May 28 and 30 was so severe that corn and soybean fields are being replanted. John Creswell (central) commented that not all corn plants have recovered from the hail damage. They are showing stress from cool, wet weather and diseased growing point. In other areas soybean plants damaged and bruised by hail are damping-off and will need to be replanted. Replanting is being hampered by rainy conditions.
  • Yellow corn is being reported in many areas. The field specialists cited several reasons, including potassium (K) deficiency symptoms, soil compaction, and lack of root development. Warmer temperatures and sun should improve the growth and appearance of the crop.
  • Chlorotic soybean plants also are being reported. Most of these problems should improve with warmer temperatures. Causes for the yellow plants include high-pH areas in fields, wet conditions, herbicide carryover, and soybean cyst nematodes. Damping-off of soybean seedlings is a problem in some areas and in severe cases fields are being replanted.
  • Postemergence herbicide applications are behind, especially for soybean. Wet conditions continue to delay herbicide application, especially in south and southeastern areas of the state.
  • Grasshopper nymphs were reported in several locations by Michael White (south), Paul Kassel, and Joel DeJong (northwest). Some field edges are being spot-treated because of defoliation occurring in the first 10 to 15 rows of soybean.
  • Most first-cut hay is in the barn or still lying on the ground. Brian Lang and William Lotz (northeast) reported that farmers have harvested one of the best hay crops they have had in many years. Potato leafhoppers are being reported on alfalfa.
  • Wheat is headed and generally looks good. Jim Jensen (southeast) reported some diseases showing up. Oat fields are in the boot stage and others are headed. Crown rust and barley yellow dwarf are present in some fields.

This article originally appeared on page 109 of the IC-480(14) -- June 15, 1998 issue.

Updated 06/14/1998 - 1:00pm