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Issue No. 18, Article 2/July 28, 2006

An Inventory of Field Crop Insect Issues in the Midwest

On July 25, extension entomologists from Illinois, Iowa, Kansas, Kentucky, Michigan, Minnesota, North Dakota, and Ohio convened during a teleconference to share information about insect situations and issues in their respective states. A synopsis of the reports follows:

Illinois (Mike Gray, Kevin Steffey)

  • Lots of corn rootworm larval damage in research plots at the Urbana location. Preliminary results will be provided in a near-future issue of the Bulletin. After thunderstorms in some areas, lodged corn resulting from rootworm larval damage was apparent.
  • Western corn rootworm adults are exhibiting dispersal behavior as they fly from one field to others.
  • Numbers of soybean aphids continue to increase slightly, but average densities (aphids per plant) still are quite low.
  • The numbers of western bean cutworm moths being captured in pheromone traps in Illinois are large in some locations, especially northwestern counties. Check out the numbers for yourself. Refer to the more detailed article in this issue of the Bulletin.

Iowa (Marlin Rice)

  • Drought conditions prevail in some areas.
  • Soybean aphids can be found in almost every soybean field, with 30 to 50 per plant being reported as the largest counts.
  • The largest densities of first-generation bean leaf beetles observed in recent years.
  • Not many reports of lodging caused by corn rootworm larval damage, although some goosenecking has been observed.
  • Densities of potato leafhoppers in alfalfa are large, and "hopperburn" is common.

Kansas (Phil Sloderbeck)

  • Numbers of soybean aphids are low.
  • Large numbers of head moths in sunflowers.

Kentucky (Doug Johnson)

  • 2006 has been a slow insect year thus far in Kentucky.
  • Only one reported find (near Lexington) of soybean aphids this year.

Michigan (Chris DiFonzo)

  • Emergence of very large numbers of adult corn rootworms. Reports of lodging related to corn rootworm larval damage have been received from many areas in the state.
  • Densities of soybean aphids have been extremely small, and no winged soybean aphids have been found in any of the suction traps in the state.

Minnesota (Ian MacRae)

  • Drought conditions prevail.
  • Densities of soybean aphids are still large in some fields, although numbers are not increasing much.
  • Twospotted spider mites are infesting some soybean fields of dry beans and soybeans.

North Dakota (Jan Knodel)

  • Drought conditions prevail.
  • 2006 has been a busy insect year in North Dakota, beginning with cutworm problems and infestations of alfalfa weevils in both first and second crops of alfalfa. The latter is not common in North Dakota.
  • Aphids have been troublesome in many crops. Soybean aphids are slowing down a bit, but numbers are still large. It is not uncommon to find 100 to 1,000 aphids per plant.
  • Sunflower head-attacking insects are making their presence known.
  • Twospotted spider mites are showing up in both dry beans and soybeans.

Ohio (Ron Hammond)

  • A couple of situations have been reported where corn rootworm larvae have caused more damage than has been true in recent years.
  • Numbers of soybean aphids are small, although they are easier to find now than they were just a week ago.
  • More potato leafhoppers have been noticed in 2006 than in recent years, and many alfalfa fields are turning yellow.

This inventory is intended to provide a snapshot of insect issues around the Midwest. We remind you that you can read more details about many of the region's insect issues in articles published in respective states' newsletters. As always, please contact any of us if you have information to share.--Kevin Steffey and Mike Gray

Kevin Steffey
Mike Gray

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