EFFECTS OF DIMBOA LEVELS IN WHEAT ON THE SUSCEPTIBILITY OF THE GRAIN APHID (SITOBION-AVENAE) TO DELTAMETHRIN

The effects of DIMBOA in cultivars of wheat on aphid antibiosis and to lerance to the insecticide deltamethrin were investigated for the aphi d Sitobion avenae. Over 48 hours the mean relative growth rate differe d significantly between nymphs of S. avenae reared on wheat cultivars containing different levels of DIMBOA. Nymphs on the resistant cv. Alt ar showed a significantly greater susceptibility to deltamethrin, with nearly a three-fold increase in the relative toxicity of deltamethrin , compared with the susceptible cv. Dollarbird. The LC50, adjusted for weight, was reduced by 91% for nymphs reared on the high DIMBOA culti var. The potential for the enhancement of predation under a reduced pe sticide regime is discussed in relation to this research.