New method of acephate application to potted plants for control of Aphis gossypii, Frankliniella occidentalis and Bemisia tabaci

Abstract

A novel method for delivering the systemic insecticide acephate was tested with chrysanthemums and gerbera daisies. The method involves applying the insecticide to the interior surface of plant pots in paint. Two paints were tested, a latex paint and SpinOut, a paint already in use for controlling plant growth. The SpinOut used lacked the cupric hydroxide component used to limit root elongation. Acephate, in the form of Orthene WPS, was applied to the pots in two separate experiments. The first was a dose-response experiment with four rates (0, 5, 15, and 25 mg/pot) to test the efficacy of acephate in paint using caged melon aphids on chrysanthemum plants conducted over a 23 day period. In this experiment Orthene in paint was also compared with a granular acephate formulation, Pinpoint 15G. The second was conducted on gerbera over 60 days and tested the efficacy of Orthene-painted pots in controlling caged melon aphids and free-flying western flower thrips and silverleaf whiteflies. In this experiment 5 rates (0, 8, 41.25, 82.5, and 165 mg/pot) of Orthene were used. In both experiments the efficacy of Orthene was compared with that of the standard rate of Pinpoint (165 mg/pot). In addition to efficacy, a marketability score of the plants and the phytotoxic effects of the two formulations were compared. Results showed that applying acephate in painted pots is a viable alternative to granular application. It reduced the effects of phytotoxicity, at equivalent rates lasts as long as the granular application, and at lower rates provides improved control over melon aphids, western flower thrips, and silverleaf whiteflies. Interestingly, the paint used may have an effect. Better control was obtained with Orthene in latex paint at lower rates and for longer than Orthene in SpinOut. It is not clear whether this was due to toxicity of latex paint, better release of acephate from latex, or possibly a synergistic effect of the latex paint.