Control of Cutworms by Spreading Poison Baits from the Air

New Zealand Journal of Agriculture, Volume 87, Issue 3, 15 September 1953, Page 204

Control of Cutworms by Spreading Poison Baits from the Air

By

G. J. GRAHAM,

Department of

Agriculture, Gisborne fN mid-December 1952 New Zealand A army worms or cutworms (Cirphis unipuncta) were - making heavy onslaughts on a number of maize crops on the Gisborne . flats. . Two farmers with areas of 100 acres sprayed their crops with 16 per cent, lindane (gamma isomer of / . benzene hexachloride) wettable powder at 1| to 21b. per acre, applied by, sprayer to the rows only, as soon as the cutworms appeared. Many cutworms were killed, but the attack was so severe that the numbers ' surviving were sufficient to continue severe damage to the crops. .. ... A third farmer tried 50 per cent, colloidal D.D.T. as a spray with similar results. . Infestation of his crop was less severe, and he decided to put up with any further loss until pupation of the caterpillars, when damage ceased. The first two farmers, however, were determined. to rout the invaders if possible and . they decided ■ to, try poison baits. As speed was essential and no other suitable mechanical distributor was available, a Tiger. Moth aeroplane fitted for aerial topdressing' was-given a quick trial to determine the efficiency of the spread of the baits. The results were satisfactory, and sufficient bait made up of a mixture of bran and wettable lindane 16 per cent, powder, with just sufficient water to fuse the two, was prepared for .the area. An adjacent flat grass paddock was used as a landing strip, and sowing of the baits on 100 acres was completed in 2 hours. Flying at 40ft. in a slight cross wind, the aeroplane

covered a strip of about 3J chains at each run. Because of shortness of time for preparation, the ground-to-air liaison was not perfect, and some small patches were missed. This did not affect the over-all result, however, the cutworm damage being stopped immediately.