The effect of alternating a resistant sorghum (Sorghum bicolor) genotype, Tx 430 x GR, and a susceptible genotype, BR 601 on the biology of the greenbug, Schizaphis graminum (Rond.) was evaluated at Embrapa/National Corn and Sorghum Research Center, Sete Lagoas, MG. Biological aspects of S. graminum were evaluated by rearing it continuously on susceptible or on resistant genotypes up to three generations or alternatively after each generation between genotypes. On average it was obtained a pre-reproductive period of 6.7 d and reproductive period of 22.6 d when the insects were reared on the susceptible genotype; on the resistant genotype the values were 7.4 and 15.3 d. The production of nymphs/female was 33.7 and 14.7 on the susceptible and resistant genotypes, respectively.
Insecta; Aphididae; greenbug; host plant resistance; Sorghum bicolor
