Degree Days - Steady as She Goes

August 19, 2009

By Rich Pope, Department of Plant Pathology

Another August week down and it was again a favorable week with nearly normal temperatures. What we need most now is to avoid extremes in temperatures throughout the next month, with periodic rainfall. Last week was actually the first in nearly two months that was, albeit slightly, above normal in heat accumulation.

degree days

Crop conditions statewide are quite good relative to the rest of the Corn Belt. Fallout from hail and high wind events remain major issues, especially in bands from Winneshiek through Fayette counties and also from Ida through Grundy counties.

Soybean aphids are the big story among pests this week. Aphids are now easily found in fields in nearly all parts of Iowa, and populations at or near the treatment threshold of 250 aphids per plant and increasing are not uncommon. Some fields are getting close to the R5.5 stage when soybeans have progressed past the stage where soybean aphid damage is significant. Good treatment decisions this coming week will be a test. With that, there are many aerial applicators active.

Rich Pope is a program specialist with responsibilities with Integrated Pest Management. Pope can be contacted at or by calling (515) 294-5899.

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