Crop Sequences for Managing Cereal Cyst Nematode and Fungal Pathogens of Winter Wheat

In the Pacific Northwest, Heterodera avenae is spreading to soils infested with root-infecting fungal pathogens of wheat. A poorly drained, silty clay foam infested with multiple pathogens was used to examine productivity of winter wheat in 11 crop sequences. Breaks between wheat crops included summer fallow or crops of pea, barley, rape, alfalfa, or Kentucky bluegrass. In the fifth year, winther wheat was planted in all sequences, after one-half of each plot was treated with aldicarb. Yield of annual winter wheat was always 40-60% less than wheat alternated with fallow or any other crop, except alfalfa contaminated with grass weeds