Effects of Chemical Seed Treatments on Wire worm Activities12

Abstract

Wire worms, Melanotus spp., were held in quart-size fruit jars containing moist soil and treated seeds to study the relative efficiencies of various insecticide seed treatments in killing them and protecting the sceds from their feeding. The abilities of the insecticide treatments investigated to kill wire worms were ranked as follows: aldrin, good; heptachlor, fair; lindane and dieldrin, mediocre; endrin, poor. Aldrin and lindane were the most repellent of these insecticides. The relatively greater repellency of aldrin, as compared with heptachlor or dieldrin, was attributed primarily to type two repellency. However the relatively high toxicity of aldrin made it first choice among the insecticides investigated, in spite of this repellency. The relatively greater repellency of lindane, as compared with heptachlor or dieldrin, was attributed to a combination of two kinds of repellency (types one and two). This repellency appears to cause lindane to rank no higher than third among the insecticides investigated from the standpoint of potential usefulne5s as a corn seed treatment for controlling wire worms. Heptachlor and dieldrin showed less type one repellency than lindane, and less type two repellency than aldrin or lindane. It was suggested that the inherent toxicity of heptachlor make it a better wire worm killer than dieldrin, and that this toxicity combined with lower degree of both type one and type two repellency make it a better wire worm killer than lindane.