Effects of Microbial, Botanical, and Synthetic Insecticides on `Red Delicious' Apple Arthropods in Arkansas

Abstract

Insecticides were compared for control of codling moth (Cydia pomonella) and oriental fruit moth (Grapholita molesta), and effects on european red mites (Panonychus ulmi) and predatory mites (Neoseiulus fallacis) in `Red Delicious' apple trees (Malus ×domestica). Ten days after treatment with azinphosmethyl, celerylooper (Anagrapha falcifera) nuclear polyhedrosis virus, rotenone-pyrethrin, or codling moth granulosis virus, fruit damage by larval codling moth and oriental fruit moth was significantly less than trees treated with Bacillus thuringiensis var. kurstaki or water (control). Trees treated with azinphosmethyl or celery looper nuclear polyhedrosis virus had fewer damaged fruit where larvae exited than did other treatments. By 21 days after the last treatment, all treatments had significantly more wormy or damaged fruit than did azinphosmethyl. At 10 days after treatment, the two viruses were more deleterious to codling moth than to oriental fruit moth causing a <1:3 ratio of these larvae compared to >3:1 ratio for the other treatments. On 16 June, 100 predatory mites were released onto the trunk of each tree. The minimum ratio of predatory mites to european red mites (>1:10) that favors biological control of european red mites occurred in all treatments by 14 July, except those treated with azinphosmethyl or rotenone-pyrethrin that had significantly more cumulative mite days of european red mites than the other treatments. The use of azinphosmethyl delayed biological control of the european red mites until 27 July whereas rotenone-pyrethrin treatment never attained biological control of the mites.