Initial and Residual Activity of Cidial (Phenthoate) Compared with that of Malathion and Lindane on Insects Affecting Stored Products1

Abstract

The initial activity of Cidial (phenthoate) (ethyl mercaptophenylacetate O, O -dimethyl phosphorodithioate) was compared with that of lindane and malathion on the following insects affecting stored products: Mediterranean flour moth, Anagasta huehniella (Zeller), larvae; khapra beetle, Trogoderma granarium Everts, larvae; lesser grain borer, Rhyzopertha dominica (F.), adults; saw-toothed grain beetle OryzaePhilus surinamensis (L.), adults; canfused flour beetle, Tribolium confusum Jacqueline duVal, larvae and adults; yellow mealworm, Tenebrio molitor L., larvae and adults; granary weevil, Sitophilus granaries (L.), adults; rice weevil, Sitophilus oriya (L.), adults. Cidial proved to be more effective than the other 2 products. Further tests were conducted to compare the residual activity of the 3 compounds. Cidial sprayed at 8 and 4 ppm on wheat gave almost complete control for at least I year of all species except T. granarium and A. kuehniella (poor control obtained after a few months). When applied at 2 ppm by spraying and at 4 ppm by dusting, this product provided almost complete control of T. confusum larvae and S. oryzae adults for I year and of some of the other species for a few months. Larvac;, used as a dust at 2 and 4 ppm, was fully effective for I year against R. dominica, S. granarius ., and S. oryzae and for a few months against T. confusum larvae; its toxicity to all the other species was limited from the outset. Malathion sprayed at 8 ppm gave almost complete kill of T. confusum larvae and S. oryzae adults for 3 months and of S. granaries for 2 months. None of the insecticides affected the germination of the seeds to any extent for I year after treatment.