Effect of Foliarly Applied Spirotetramat on Reproduction of Heterodera avenae on Wheat Roots.

The cereal cyst nematode, Heterodera avenae, has the potential to reduce yields of cereal crops in the Pacific Northwest. Spirotetramat (Movento) is a foliar-applied insecticide with ambimobile translocation that reduces fecundity of sucking insects which feed on roots as well as foliage. Spirotetramat (88 g/ha) was applied to foliage during 2010 in two wheat fields infested by H. avenae near St. Anthony, ID and Palouse, WA. In Idaho, two applications at 2-week intervals during late spring to plants already exhibiting swollen white females reduced the postharvest density of H. avenae eggs plus juveniles by 35% (P = 0.03) compared to the nontreated control. In Washington, a single application before white females became apparent reduced the nematode density by 78% (P = 0.01). Grain yields and test weights were not significantly affected by application of spirotetramat at either location. In addition, symptomatic plants from the Idaho field were transplanted into greenhouse pots and treated with spirotetramat. One application (110 g/ha) reduced numbers of eggs plus juveniles/plant by 78% (P = 0.02). Spirotetramat effectively reduced H. avenae populations and warrants further evaluation as a substitute for crop rotations or long fallow periods that reduce nematode population densities in infested fields.