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Field crop health matters throughout the entire growing season. The types of diseases on crops depend on the point in the growing season and the environmental conditions. Many later-season diseases result from soilborne pathogens over which in-season fungicide applications have no control. Most commercial varieties will have ratings for the performance of their selections against various diseases, including those caused by soilborne pathogens.

Although some parts of Iowa have been catching up with moisture deficits, many areas continue to be in severe drought. Drought stress combined with high temperatures is good news for field crop pests like grasshoppers and spider mites. We’ve been getting reports of high grasshopper numbers around the state this year. If your area is hot and dry, consider scouting fields now and throughout August.

Several labs in the Midwest have been monitoring the distribution of soybean gall midge in Iowa since 2018. Last year, we sampled many counties in western Iowa but only confirmed three new counties. This year, we focused on the counties just east of the distribution in 2021 and were able to confirm eight new counties in Iowa that had soybean gall midge: Humboldt, Kossuth, Palo Alto, Pocahontas, Polk, Ringgold, Warren, and Webster (Figure 1). Iowa now has 42 counties confirmed with soybean gall midge, nearly half of the state.

Western and northern corn rootworms are serious pests of corn throughout the Corn Belt (Photo 1). We recommend that farmers scout every cornfield every year, regardless of the management tactic(s) used, to evaluate management decisions and prepare for next year. It is a good idea to scout for larvae early in the season, assess root injury when larval feeding wraps up, and monitor adults later in the season.