The Effectiveness of Some Insecticides on Several Vegetable Crops1

Abstract

Six insecticides were tested on vegetable crops for phytotoxicity, effectiveness against insects, and effect on flavor and quality of some of the crops. At rates below those usually recommended, Thiodan® (6,7,8,9,10,10-hexaehloro-1,5,5a,6,9,9a,-hexahydro- 6, 9- methano-2, 4, 3-benzodioxatheipin-3-oxide), ethion, malathion, Dibrom® ( O,O -dimethyl- O -(1, 2-dibromo-2, 2-dichloroethyl) phosphate), Sevin® ( N -methyl-1-naphthyl carbamate), and Trithion® ( S -(p-chlorophinylthio) methyl O,O -diethyl phosphorodithioate) showed no phytotoxicity to cucumber, cantaloupe, tomato, potato, snap bean, lima bean, cabbage, and eggplant. Yields from eggplant and cabbage were significantly in- creased by sprays of Thiodan, ethion, malathion, Dibrom, and Trithion. Yields of cabbage were significantly increased by Sevin. Yields of tomato, potato, cucumber, and cantaloupe were not significantly increased by any of the insecticides. All materials used were highly effective against the eggplant lace bug, ( Gargaphia solani Heid.), the margined blister beetle ( Epicauta pestifera Werner), the cabbage looper ( Trichoplusia ni (Hbn.)). the imported cabbageworm ( Pieris rapae (L.)), the potato leafhopper ( Empoasca fabae (Harris)), and the Mexican bean beetle ( Epilachna varivestis Muls.). Thiodan was most effective against the cabbage flea beetle ( Phyllotreta cruciferae (Goeze)) and the corn earworm ( Heliothis zea (Boddie)). Sevin was effective against the melon aphid ( Aphis gossypii Glov.) but not the potato aphid ( Macrosiphum solanifolii (Ashm.). Trithion and ethion were highly effective against the two-spotted spider mite ( Tetranychus telarius (L.)). Thiodan and Trithion gave excellent control of the potato aphid. No off-flavors were detected in any of the crops.