The Mode of Action of Endrin on the Bean Stem Miner, Melanagromyza sojae, with Special Reference to Its Translocation in Soybean Plants1

Abstract

The bean stem miner ( Melanagromyza sojae (Zehntner)) is one of the most destructive pests on young soybeans in Formosa. The larvae feed on the pith of the soybean stem. The infested young plants are stunted in their subsequent growth, producing a poor yield. Of 10 insecticides tested, endrin emulsion gave the best residual control. When applied on 8- to 11-day-old summer plants, one foliar spray at such relatively low dosages as 90 g. of the active ingredient per hectare was usually effective to protect the plants from damage almost completely for about 15 days. Although endrin emulsion showed some degree of repellent action against the ovipositing flies, its persistent effect was caused by the kill of the newly hatched larvae by the toxieant translocated from the initial deposit into the post treatment growth of the plants in which the eggs are laid. Translocation of endrin applied to various parts of young soybean plants and to the surface of soil into the feeding sites of the newly hatched larvae was also studied with normal and abnormally larger dosages of this insecticide.