Russian wheat aphid (Kansas Wheat)

Persistent high populations of Russian wheat aphids can lead to serious crop losses. The recommended threshold for treatment varies with the time of year and the expected yield. Populations that develop soon after the crop emerges in early fall can be damaging but are unusual in Kansas. At this time, a 20 to 30 percent infestation of plants may warrant treatment. In spring if wheat has yield potential of at least 20 bushels per acre, treatment should be considered when 20 percent of tillers show symptoms and most have live aphids. In fields with a yield potential of 40 bushels or more, it may be economical to treat when as few as 10 percent of tillers are infested. When 30 to 40 percent of primary tillers are infested between flowering and the soft-dough stage, treatment may be advisable, but infestations confined to late-developing secondary tillers are less damaging to yield.