A more accurate method to determine the need for treatment is to walk a diagonal or zigzag pattern across the field, stop 10 times and collect 10 tillers at random at each stop. More efficient sampling procedures are described in Sampling Russian Wheat Aphid in the Western Great Plains , Great Plains Agricultural Council Publication 138. After flowering, substitute 500 for 200 in the numerator of the formula. If the calculated ET is lower than the percent infested tillers observed, a treatment should be cost effective. There probably is no benefit from insecticide applications made after the crop has reached the soft dough stage.
Scout fields at least weekly in the spring.
Spring foliar treatments have been the most common type of treatment in Colorado over the past 10 years. Both cool temperatures and drought stress can interfere with the plant's ability to absorb systemic insecticides. Make ground applications in at least 10 gallons of spray volume per acre. Aerial applications can be made in one gallon of spray volume per acre prior to jointing and after flowering. Otherwise, use 2 gallons per acre.