Susceptibility of Northern Corn Rootworm Adults to Aldrin in Ohio1

Abstract

Field-collected adults of northern corn rootworm Diabrotica Longicornis (Say), were treated with insecticideacetone solutions by topical application to determine variation in aldrin susceptibility between populations during 1963 and 1964. Periodic mortality tests were conducted to determine if the toxicity of aldrin to field-collected aldrin susceptible adults is related to the time of season that beetles were collected. It appears that approximately 10 years of aldrin or heptachlor soil treatment are necessary before aldrin resistance becomes a problem. However, aldrin or heptachlor soil treatment for over 10 years does not always result in aldrin-resistant populations. The LC₅₀ value for beetles collected 14 days after the first adult was observed in the field was lower than values obtained with beetles collected late in the growing season. Aldrin-resistant adults of northern corn rootworm are cross resistant to heptachlor.