Toxicity of fruit fly baits to beneficial insects in citrus.
Two fruit fly baits, Nu-Lure/malathion and GF-120 (Spinosad) were evaluated in the laboratory for non-target impacts on beneficial insects. Nu-Lure/malathion proved attractive and toxic to adults and larvae of the coccinellid species, Curinus coeruleus Mulsant, Cycloneda sanguinea L. and Harmonia axyridis Pallas, a lacewing species, Chrysoperla rufilabris Burmeister. The coccinellids Olla v-nigrum Mulsant, Scymnus sp. and nymphs of the insidious flower bug, Orius insidiosus (Say) did not succumb to Nu-Lure baits, even in no-choice situations. Nu-Lure was also attractive and lethal to adults of two aphidophagous flies; Leucopis sp. and the syrphid fly Pseudodorus clavatus (F.). Both Nu-Lure and GF-120 caused significant mortality to the parasitoid wasps, Aphytis melinus De Bach and Lysiphlebus testaceipes Cresson, within 24 h of exposure. However, GF-120 caused no significant mortality to any coccinellid in either choice or no-choice situations, despite considerable consumption of baits. Adults of P. clavatus tended to avoid GF-120, although mortality was significant in no-choice tests. Although larvae and adults of the lacewing C. rufilabris consumed GF-120, mortality was delayed; adults died 48 -96 h post-exposure and those exposed as larvae died two weeks later in the pupal stage. The Nu-Lure bait did not appear palatable to any of the insects, but the high concentration of malathion (195,000 ppm) caused rapid mortality to susceptible insects. Nu-Lure bait without malathion also caused significant mortality to flies and lacewings in cage trials. Although GF-120 bait appeared more benign overall, further research efforts are warranted to increase its selectivity for target fly species and reduce its attractiveness to parasitoids and lacewings. I conclude that the Florida "fly free zone" protocol in its current form is not compatible with an IPM approach to commercial citrus production.
Michaud
J P
JP
Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA. jpmi@ksu.edu
D000818:Animals; D002957:Citrus / Q000469:parasitology*; D004338:Drug Combinations; D007300:Insect Control / Q000379:methods*; D007313:Insecta / Q000187:drug effects*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva; D018942:Macrolides / Q000633:toxicity*; D008294:Malathion / Q000633:toxicity*; D009758:Nymph
D004338:Drug Combinations; D007306:Insecticides; D018942:Macrolides; D008294:Malathion; C415329:spinosad