Residual toxicity of pesticides used for control of lepidopteran insects in citrus to the predaceous mite Euseius stipulatus Athias‐Henriot (Acarina, Phytoseiidae)

Abstract

Fourteen compounds used for suppression of lepidopteran pests of citrus were applied in a commercial manner to citrus trees. Amounts of dislodegable residues, together with mortality and fertility of Euseius stipulatus Athias-Henriot confined on treated foliage, were monitored for up to 100 days post-treatment. Several materials had little effect on E. stipulutus after seven days post-treatment.These included cryolite, trichlorfon, naled, parathjon? chlorpyrifos, mevinphos, and a formulation of Bacillus thuvingiensis endotoxin. Carbosul an, thiodicarb, methomyl and two formulations of carbaryl caused mortality for up to 30 days. Fluvalinate and esfenvalerate caused the greatest mortalities for up to 60 days post-treatment. Mortality was correlated with amounts of dislodegable residue for each material tested. There was little effect on fertility by any compound. Materials and methods Field treatmentsThe pesticides used in this study were those most widely used against lepidopteran insects attacking citrus, together with a few compounds yet unregistered for this use. The materials used (together with their formulations, use rates and sources) were the pyrethroids esfenvalerate (Asana 1.9 EC, U.S.

TOXICITY OF INSECTICIDES USED IN CITRUS TO APHYTIS MELINUS DEBACH (HYMENOPTERA: APHELINIDAE) AND RHIZOBIUS LOPHANTHAE (BLAISD.) (COLEOPTERA: COCCINELLIDAE)

“…rnelinus and for 12 of the 23 compounds tested against R. lophanthae (Tables 1 and 2). Slopes of these relationships ranged between 1.0 and 2.6, and were similar to those reported in tests of other insecticide residues Bellows et al 1992Bellows et al , 1993. In the present tests, the insects were exposed to recently deposited insecticide by walking and other activity on the leaf surface as well as through evaporation of the insecticide into the atmosphere, as opposed to being treated directly with the insecticide, and this difference in mode of contact may account for the lower slopes.…”

“…Longer term impacts result from the amount of toxic residues present following treatment. Some insecticides dissipate rather quickly and have short residual impact, others decompose~into compounds more toxic than the parent material, and others have longer residual half-lives and can affect natural enemy populations for considerable lengths of time (Bellows et al 1985;Morse et al 1987;Bellows and Morse 1988;Bellows et al 1988Bellows et al ,1992Bellows et al , 1993. These longer term effects include both mortality and sublethal ones.…”

“…A number of pests are suppressed by natural enemies, but other pests are subject to chemical treatments. The long-term residual effects of several insecticides used in citrus production on a number of beneficial organisms, including parasitic Hymenoptera and predaceous mites and beetles, have been examined (Bellows et al 1985;Morse et al 1987; Bellows and Morse 1988;Bellows et al 1988Bellows et al , 1992Bellows et al , 1993. The immediate effects of many of these insecticides have not been studied, and must be quantified to understand fully the significance of insecticides selected for use in any particular management scheme.…”

RESIDUAL TOXICITY OF PESTICIDES USED FOR LEPIDOPTERAN INSECT CONTROL ON CITRUS TO APHYTIS MELINUS DEBACH (HYMENOPTERA: APHELINIDAE)

“…The rates of residue dissipation obtained in the present study agree with those found in earlier studies (Bellows and Morse 1988) for parathion and chlorpyrifos, which dissipated rapidly, and for carbaryl, which dissipated more slowly. The initial depositions and dissipation rates for all materials agreed quite closely with a similar study with these materials (Bellows et al 1992).…”

Effect of pesticide residues on mortality of Aphytis melinus DeBach (Hym., Aphelinidae) in Munger cells and larger containers

“…Three series of bioassays were conducted for each treatment on each sample date using adult Aphytis melinus DeBach of mixed sex obtained from a commercial insectary. The first of these was a bioassay conducted in Munger cells (MUNGER, 1942; using methods described more fully elsewhere (BELLOWS et al, 1985;BELLOWS and MORSE 1988;BELLOWS et al, 1988). Ten Munger cells were set up, each exposing a 3.2 cm diam.…”