Status of Insecticide Resistance in Insects Attacking Vegetable Crops

Abstract

Intensive treatment of vegetable crops with the organic insecticides has produced several instances of insect resistance to these materials. Similar treatment over much longer periods with inorganic insecticides, however, did not produce such resistance. Considering the large total number of vegetable pests, relatively few have developed insecitcidal resistance, but these resistant insects constitute the most pressing problems in vegetable insect control at the present time. Vegetable pests, exclusive of the mites, which have developed a definite resistance to insecticides, include the following: imported cabbageworm (<i>Pieris rapae</i> (L.)), cabbage looper (<i>Trichoplusia ni</i> (Hbn.)), diamondback moth (<i>Plutella maculipennis</i> (Curt.)), tomato fruitworm, (<i>Heliothis zea</i> (Boddie)), salt-marsh eaterpillar (<i>Estigmene acrea</i> (Drury)), Colorado potato beetle (<i>Leptinotarsa decemlineata</i> (Say)), potato flea beetle (<i>Epitrix cucumeris</i> (Harr.)), southern potato wireworm (<i>Conoderus falli</i> Lane), Mexican bean beetle (<i>Epilachna varivestis</i> Muls.), onion maggot (<i>Hylemya antiqua</i> (Mcig.)), carrot rust fly (<i>Psita rosae</i> (F.)), vinegar fly (<i>Drosophila</i> sp.), serpentine leaf miner (<i>Liriomyza pusilla</i> (Meig.)), onion thrips (<i>Thrips tabuci</i> Lind.), lygus bugs, green peach aphid (<i>Myzus persicae</i> (Sulz.)), and melon aphid (<i>Aphis gossypii</i> Glov.) with a possibility of resistance in potato aphid (<i>Macro-siphum solanifolii</i> (Ashm.), tomato hornworm (<i>Protoparce quinquemaculata</i> (Haw.)), European corn borer (<i>Pyrausta nubialis</i> (Hbn.)), beet armyworm (<i>Laphygma exigua</i> (Hbn.)), southern garden leafhopper (<i>Empoasea solana</i> DeL.), and garden symphylid (<i>Scutigerella immaculata</i> (Nwp.)). The vegetable insects which have developed resistance are for the most part, the logical ones to have done so. The biology and habits of at least some of the resistant forms differ markedly from that of the nonresistant strains. Although the prediction of the development and spread of resistance is extremely difficult, it is believed that by a study of the biology, habits, and insecticide control program being used at least some educated guesses can be made in this respect. The possible solution to the problem by reporting instances of resistance, testing for tolerance, and changing insecticides before control failure occurs, is discussed.