The Concentration Of Wireworms by Baits Before Soil Fumigation With Calcium Cyanide

Abstract

Applications of 200 to 300 pounds of granular calcium cyanide to the acre with a grain drill under certain conditions will kill a high percentage of the wireworms in the soil, but ordinarily this treatment is too expensive for commercial use. Therefore, advantage was taken of the fact that wireworms will collect in rows or hills of seeds, and several kinds of seeds were planted as baits to concentrate the wireworms in rows. By this method a fairly heavy dosage can be applied to the baited rows, and the amount required to the acre will be considerably less than in broadcast treatment. Beans, peas, and corn all proved satisfactory attractants and concentrated;' large percentage of the wireworms in the rows. The effectiveness of the baits was reduced if other foods, such as the remains of an old crop, were left in the field. Experiments showed that the most satisfactory amount of calcium cyanide, considering both the lethal effect and the cost, was 5 to 5.5 pounds per 1,000 feet of row. For baited rows 2 1/2 feet apart this will amount to a little less than 100 pounds per acre, and for rows of greater or less width, the quantity will be decreased or increased accordingly. The percentage of wireworms attracted to the baits decreased as the width of the rows increased, being 96 per cent for 2-foot rows and 80 per cent for 4-foot rows. Commerial applications by several growers gave satisfactory results.