Insect numbers are higher than normal

This information was summarized from a May 8 teleconference with ISU Extension field specialists in crops.

  • Farmers in most areas of the state have planted more than 95 percent of their corn acres. Most corn is emerged. Soybean planting is typically 60 to 90 percent completed with up to 60 percent emerged (in southern counties). Scattered rains of up to an inch occurred across the state during the early morning of May 8.
  • Many cornfields have large infestations of corn flea beetles. Insecticide treatment of some fields has occurred during the past week, especially in the southern two-thirds of the state. Populations of corn flea beetles seem to be declining, so check the numbers of beetles because treatment may not be necessary (see article in May 1 ICM newsletter).
  • Bean leaf beetles are feeding on newly emerged soybean plants. See article on pages 71-72 for threshold and treatment information.
  • Spraying has occurred in some alfalfa fields that are at threshold levels for alfalfa weevils. Other fields have been cut to take care of the alfalfa weevil population. A few potato leafhoppers are showing up in alfalfa.
  • Pastures are dry and slow growing in most areas. The oat crop is reported to be good in most areas. Winter wheat in southern Iowa is starting to head.
  • Waterhemp and woolly cupgrass are starting to germinate. Weeds are beginning to break through preemergence herbicide treatments, especially in areas with dry soil.

This article originally appeared on page 71 of the IC-484 (9) -- May 15, 2000 issue.

Updated 05/14/2000 - 1:00pm