Pest problems include bean leaf beetle and potato leafhopper

This information was summarized from an August 12 teleconference with Iowa State University extension field and campus specialists in crops.

  • Variable rainfall has occurred during the last several weeks. Conditions in the extreme southwestern, southeastern, and some northwestern counties are extremely dry and the crops are in poor shape. Rain that fell in the northwest a week ago is especially helping the soybean crop. Crops are generally progressing well in the rest of the state.
  • Corn growth stage ranges from R3 (milk) to R5 (dent). Corn rootworm damage to the roots and lodging is severe in some fields. Some of the damaged fields were treated in the spring with soil-applied rootworm insecticide. Grasshoppers have been a problem in some areas, especially where it is dry.
  • Soybean growth stage is mainly R4 (full pod) to R5 (beginning seed). Sudden death syndrome is common in a few fields, especially in Cedar, Louisa, and Muscatine counties. First-generation bean leaf beetle populations are high in some fields and second-generation beetles are beginning to emerge. Treatment will occur during the next several weeks for those fields with high numbers of bean leaf beetles. Soybean aphid numbers have been declining in most areas, although scattered fields have been treated. Potassium deficiency symptoms along with iron chlorosis and soybean cyst nematode were reported. Japanese beetles are being reported and are causing some damage to soybean.
  • Second-cut harvest of hay is almost complete. Some third-cut alfalfa harvest is beginning. Potato leafhopper over threshold levels and subsequent treatment of this pest were reported in alfalfa.
  • In the areas of the state with little rainfall, the pastures are gone. In areas that received rain, the pastures are beginning to recover.

This article originally appeared on page 171 of the IC-488(20) -- August 19, 2002 issue.

Updated 08/18/2002 - 1:00pm