Evaluation of New Insecticide Application Strategies for Controlling the Sunflower Moth (Lepidoptera: Pyralidae) on Sunflower

Abstract

Strategies for reducing chemical use on sunflower ( Helianthus annus L.) for control of Homoeosoma electellum (Hulst) with either parathion or pyrethroids were evaluated. One application of parathion (an insecticide with a short residual life) to sunflowers when 15, 20, 25, 30, and 35% of the plants were flowering did not protect sunflowers from larval infestations. Multiple applications controlled larvae, improved yields, and reduced Rhizopus sp. infections, but the initiation of control before 35% of the plants bloomed had no advantage. Multiple applications were compared to the current recommendation that applications be initiated when 20% of the plants flower. Initiating parathion applications when 35, 70, and 100% of the plants were flowering coincided with the time when larvae would still be exposed to insecticides applied to the flower. Pyrethroids, which have long residual activity, effectively controlled infestations with two applications and were effective with a single application when the infestation was light. These data demonstrate that delayed initial application of parathion and use of pyrethroid insecticides are effective strategies for control of H. electellum .