Toxicity of Cypermethrin on the neotropical lacewing chrysoperla externa (Neuroptera:Chrysopidae)

-HARAMBOURE M; FRANCESENA N; REBOREDO GR; SMAGGHE G; ALZOGARAY RA AND SCHNEIDER MI

Communications in Agricultural and Applied Biological Sciences

Ghent University

Lugar: Ghent; Año: 2013 vol. 78 p. 339 - 344

1379 1176

SUMMARYThe generalist predator Chrysoperla externa (Neuroptera: Chrysopidae) is distributed in the NeotropicalRegion and presents a strong potential as a biological control agent due to its easily rearing, high voracityand tolerance to several pesticides. This species feeds on relevant pests such as aphids, whiteflies, tripsand various lepidopterans. In Argentina, an indiscriminate chemical control with broad spectrum pesti-cides is still the first option for controlling pests causing resistance problems and reduction of beneficialorganisms. Therefore, it would be desirable that predators or parasitoids develop tolerance or resistanceas phytophagous pests for their maintenance in the agricultural ecosystems. The objective of this workwas to evaluate the tolerance of C. externa to the pyrethroid cypermethrin by topical exposure in labora-tory conditions. The symptoms evaluated were tremors, movement, knockdown, inability to walk due tobeing glued. Recovery from poisoning symptoms was also evaluated. Six different concentrations of thepesticide, including the full field one, were tested. The exposure method was by topical applications onthird larval instar. A low toxicity on larvae at 24 h post-treatment was observed, even at the highest con-centration evaluated. Most of treated individuals looked normal at 24 h post-treatment; those who wereknocked down showed a complete recovery between 48 and 72 h post-treatment. C. externa demon-strated a high tolerance to pyrethroids. This could be due to the activity involved in pyrethroids biotrans-formation (for example, esterases and mixed-function oxidases), or to a low sensitivity of the moleculartarget. Future studies should be addressed at biochemical and molecular levels to complete ourknowledge about insecticide effects on this predator.