Biological effects of combining carboxin, organomercury fungicides and insecticides as seed dressings for wheat, and the effect of these combinations on adherence of the pesticides to the seed

Abstract

AbstractWhen seeds of winter wheat were carefully dressed in the laboratory with combinations of fungicides (organomercury alone or organomercury plus the systemic fungicide carboxin) and insecticides (aldrin, carbophenothion or chlorfenvinphos as liquid formulations, or a γ‐BHC powder formulation) so as to ensure that nearly all the recommended amounts of the active ingredients stuck to them, the insecticides gave good insect control, but γ‐BHC with organomercury fungicide decreased the number of plants that germinated, and γ‐BHC with carboxin and organomercury was even more damaging.Commercially dressed seeds had only about 30 to 60% of the target dose of fungicides, but more than 80% of the target doses of the liquid insecticides aldrin, carbophenothion and chlorfenvinphos. With combinations of powder fungicide and liquid insecticide, greater amounts of pesticide on the seed were obtained if the insecticide was put on first.Because of unusually late sowings and little fungal infestation, neither laboratory nor commercially treated seeds provided good tests for control of smut.