Effects of Seed Treatments and a Soil-applied Nematicide on Corn Yields and Nematode Population Densities

Plant-parasitic nematodes are microscopic worms that feed on plants. Almost every nematode that feeds on corn is capable of feeding on many other plants. These nematode parasites are thought to be native to most Iowa soils and to have fed upon native plants before corn was grown as a cultivated crop. Population densities (numbers) of most species of plant-parasitic nematodes that feed on corn have to increase to damaging levels (called damage thresholds) before yield loss occurs.

Soybean Aphid Efficacy Evaluation

Soybean (Glycine max), grown in Iowa and most of the north central region of the United States, has not required regular insecticide use. The soybean aphid, Aphis glycines (Hemiptera: Aphididae), causes yield losses from direct plant feeding, and has been shown to transmit several plant viruses. In Iowa, soybean aphid can colonize soybean fields in June and has developed into outbreaks in July and August capable of reducing yields by nearly 40 percent.