Response of the Predatory Mite Phytoseiulus macropilis (Acari: Phytoseiidae) to Pesticides and Kairomones of Three Spider Mite Species (Acari: Tetranychidae), and Non-Prey Food

Muhammad M. Amin, Russell F. Mizell, III, R. Wills Flowers


The predatory mite Phytoseiulus macropilis Banks (Acari: Phytoseiidae) is native to Florida. Some biology and ecology of this phytoseiid have been documented, but its potential as a biological control agent of phytophagous mites (Acari: Tetranychidae) has received less attention. The response of P. macropilis to 12 acaricides, 3 tetranychid mite species and 5 potential alternate foods was evaluated in laboratory bioassays. Pesticide residual effects on P. macropilis were evaluated by a double-disk leaf residue method. The synthetic pyrethroids Tame (fenpropathrin), Cymbush (Cypermethrin) and Mavrik (fluvalinate) were highly toxic. Tolerance was observed to the acaricides, Omite (propargite), and Avid (abamectin), while Vendex (hexakis), Pentac (dienochlor), and Kelthane (dicofol) were highly toxic. The insecticides Orthene (acephate) and Diazinon and the fungicides, Domain (thiophanatemethyl) and Cleary (thiophanate) were not toxic to P. macropilis. Field efficacy tests of fenpropathrin and dicofol indicated that these chemicals lose toxicity to P. macropilis 21 and 7 d after application, respectively. In olfactometer bioassays, female predators were attracted to kairomones produced by their rearing host Tetranychus urticae Koch on bean leaves but not to kairomones of the tetranychids Oligonychus ununguis (Jacobi) and T. evansi Baker and Pitchard on their respective host plants. Predators did not respond significantly to selected alternate foods: pollen from the hybrid daylily Hemerocallis spp., Phylloxera spp. larvae, eggs of false oleander scale Pseudaulacaspis cockerelli (Cooley), a sugar-water solution and water. This study identified several pesticides that could be integrated with use of P. macropilis as a biological control. Results also indicate that the predator may have a narrow prey range and require specific species of mite prey for survival and oviposition.

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