Determinação do período de avaliação de não-preferência de sorgo ao pulgão-verde, Schizaphis graminum (Rond.) (Homoptera: Aphididae).

To determine the evaluation period of preference of the greenbug, Schizaphis graminum (Rond.) to sorghum (Sorghum bicolor) genotypes, a study was conducted at the Embrapa/National Corn and Sorghum Research Center, Sete Lagoas, MG, using different sources of resistance. Cultivars were randomized within pots and 11-d after planting five apterous adult greenbugs/plant were released in the center of the pot. Evaluation based on the number of insects in each genotypes, after 24, 48, 72 and 96 hours of the insects release indicated that 72 hours after infestation was the ideal period to evaluate the non-preference of S. graminum to sorghum