Planting Date, Seed Treatment and Foliar Fungicide Effects On Soybean.

Soybean [Glycine max (L.) Merr.] growers have an ever-increasing number of management options including seed treatments that combine fungicidal and insecticidal activity and effective foliar fungicides.  This 2-yr study compared soybean planting dates with and without seed-applied fungicide/insecticide treatments. In addition, foliar fungicides were compared across the two planting dates and on soybean with and without seed treatments.  Use of a seed treatment increased soybean plant populations at both planting dates (eight percent early and four percent late). Yield of treated vs. untreated soybean seed were 15 and five percent greater, respectively, when soybean were planted in early May vs. early June.  Treatment with foliar fungicides consistently delayed leaf senescence and maturation, but did not provide consistent yield increases in these environments.  Results from this study indicate that when planting into cool soils in early May, Kansas soybean growers should consider planting seed treated with an appropriate fungicide/insecticide combination.