The aphids that spread yellow dwarf viruses are more active during warm conditions in the late spring and summer. Plants infected in the seedling stage are the most severely damaged. Early-planted oats typically suffer less yield loss because they are older during the period of the greatest aphid activity. On winter wheat, planting date has the opposite effect on yellow dwarf severity. Earlier-planted crops have more problems because aphids are still active during the seedling stage of the crop.
Winter wheat planted after the Hessian fly-free date usually escapes fall infection by the virus.
These crops can still be infected in the spring, but the impact of spring infection on winter wheat is usually minimal. Patches of stunted, yellowed plants due to barley yellow dwarf virus in wheat. Barley yellow dwarf virus in wheat, with healthy plants on the left. Management of barley yellow dwarf virus depends on planting date and genetic resistance. Resistance is available in oat and wheat varieties, and new sources, including transgenic, are being investigated.