Wireworm Control on Potatoes in Idaho with Side-Dressed and Broadcast Insecticides123

Abstract

Side-dressed and broadcast applications of insecticides Were evaluated for wireworm, mostly sugarbeet wire-worm, Limonius californicus (Mannerheim), control on potatoes in 2 separate field experiments in Idaho. In the 1st experiment, Bay-38156 (O-ethyl-S-p-tolyl ethyl-phosphonodithioate) and disulfoton were side-dressed at rates of 8 ami 18, Agritox® (O-ethyl 0-2,4,5-trichloro-phenyl ethylphosphonothioate) and Dasanit® (O, O-diethyl O-[p- (methylsulfinyl) phenyl] phosphorothioate) at 0.8 and 1.8, and propoxur at 0.9 and 1.7 oz active in gredient (AI) /1000 ft of row. All treatments resulted in significant reductions in wireworm injury. The treatments are listed in the following order of decreasing effectiveness: llay-38156 > disulfoton > Dasanit and propoxur > untreated control. Control with Agritox was midway between that with disulfoton and Dasanit, but not signilificantlv different from either. In the 2nd experiment, chlordane was broadcast at the rate 10 lb; diazinon and parathion at 6 lb, phoxim at 3 lb, and Dyfonate® (O-ethyl-S-phenyl ethylphosphono dithioate) and Agritox at 4 lb AI/acre. Phorate was side dressed at 2.3 oz and dichlorvos at 3,8 oz AI/1000 ft of row. Each plot was paired with an untreated control. Reductions in damage to tubers were: Agritox, Dyfonate, and chlordane> parathion> phorate, Damage in plots treated with phoxim, dichlorvos, and diazinon did not differ from that in plots treated with Agritox, Dyfonate, and chlordane or from the plots treated with parathion, Dichlorvos side-dressed at 12.4 and 3.8 oz AI/1000 ft of row resulted in better control than that obtained with 2.0 oz. None of the chemicals gave satisfactory control. If wireworm control were to depend on one of the organo-phosphate materials, the wireworm population would be expected to increase slowly until wireworm injury again would be be of the major problems confronting potato growers in Idaho.