COMPARATIVE EFFICACY OF INSECTICIDES AGAINST TUBER FLEA BEETLE AND APHIDS IN POTATOES IN BRITISH COLUMBIA

One organochlorine, one synthetic pyrethroid, three carbamate and 11 organophosphorus compounds were tested against the tuber flea beetle, Epitrix tuberis Gent., and aphids, mainly Myzus persicae (Sulz.), on potatoes, Solanum tuberosum L. The insecticides were applied as granules only, granules with three supplementary sprays, or sprays alone at 10-day intervals. No treatment was completely satisfactory for both pests. Larval damage to the tubers was reduced significantly by granules of isofenphos, by granules with sprays of carbofuran and N 2596 (S-[p-chlorophenyl] O-ethyl ethanephosphorodithioate) and by sprays of methidathion and NRDC 143 (3-phenoxybenzyl (±)-cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate), the synthetic pyrethroid. Only the last two, and carbofuran, reduced the amount of adult beetle feeding. Aphid numbers were not reduced significantly by any treatment, but were increased significantly by three.