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

A novel method for delivering the systemic insecticide acephate was tested with chrysanthemums and gerbera daisies. The method involves applying the i nsecticide 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 p lant growth. The SpinOut used lacked the cupric hydroxide component used to limit root elongation. Acephate, in the form of Orthene WPS, was applied t o the pots in two separate experiments. The first was a dose-response exper iment with four rates (0, 5, 15, and 25 mg/pot) to test the efficacy of ace phate in paint using caged melon aphids on chrysanthemum plants conducted o ver a 23 day period. In this experiment Orthene in paint was also compared with a granular acephate formulation, Pinpoint 15G. The second was conducte d on gerbera over 60 days and tested the efficacy of Orthene-painted pots i n 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 1 65 mg/pot) of Orthene were used. In both experiments the efficacy of Orthen e 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 phytotoxi c effects of the two formulations were compared. Results showed that applyi ng acephate in painted pots is a viable alternative to granular application . It reduced the effects of phytotoxicity, at equivalent rates lasts as lon g as the granular application, and at lower rates provides improved control over melon aphids, western Bower thrips, and silverleaf whiteflies. Intere stingly, the paint used may have an effect. Better control was obtained wit h Orthene in latex paint at lower rates and for longer than Orthene in Spin Out. It is not clear whether this was due to toxicity of latex paint, bette r release of acephate from latex, or possibly a synergistic effect of the l atex paint. (C) 2000 Elsevier Science Ltd. All rights reserved.