Soybean aphid populations around Iowa continue to remain below the economic threshold in most areas reported by extension field agronomists on July 16.
The one exception continues to be in northeastern Iowa where Brian Lang notes that the population in his research site near Decorah has gone from 30 per plant on June 28 to 405 per plant on July 5, to 1,137 per plant on July 12 (Table 1). Soybean fields in northeastern Iowa should be scouted now and an insecticide application should be considered when the population exceeds 250 aphids per plant on 80 percent or more of the plants. For more information, see ICM, July 9, pages 217-218.
Iowa State University
Rice, Marlin E. and O'Neal, Matthew E., "Mid-July soybean aphid update" (2007). Integrated Crop Management News. 1023.
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