Malathion Bait Sprays for Control of Apple Maggot (Diptera: Tephritidae)

Abstract

Malathion (1.2 g [Al]/liter, applied at 2-wk intervals for a total of four spray applications) was compared with malathion mixed with 0.25 and 0.5% Nu lure bait for control of the apple maggot, Rhagoletis Pomona ella (Walsh), in 1986 and 1987 seasons. Apples sprayed with malathion mixed with Nu lure had the lowest fruit injury in both years. In 1986, fruit injury averaged 18.3 ± 16.4% (x ± SEM) in apples treated with malathion bait mixture compared with 39.0 ± 9.5% in apples treated with malathion alone and 56.3 ± 15.5% in untreated apples. In 1987, apple maggot injury in apples treated with malathion bait mixture averaged 3.7 ± 3.2% compared with 45.7 ± 2.7% in apples treated with malathion alone and 26.7 ± 22.2% in untreated apples. Laboratory bios says of residual toxicities of malathion against apple maggot adults at a rate of 1.2 g (AI)/liter indicated efficacy of <1 wk and complete ineffectiveness within 12 d after application on apple foliage and fruits. At the higher rate of 2.4 g (AI)/liter, only 17%mortality was noticed 16 d after application. Further laboratory tests indicated total adult mortality within 48 h and negligible rates of opposition (<1 egg per female) in apples treated with malathion at rates of 0.3 and 0.6 g (AI)/liter mixed with 1% Nu lure bait. In apples treated with malathion alone, 29 ± 7.7% mortality occurred and 10 eggs per female were deposited at the end of 48 h for 0.3 (AI)/liter rate, and 21 ± 7.7% mortality occurred and 16 eggs per female were deposited for 0.6 g (AI)/liter rate. Nu lure alone at 1% had no adverse effects on survival and opposition of apple maggot females. Results of these field and laboratory experiments showed that addition of Nu lure bait to malathion increased adult mortality and reduced opposition in treated apples.