Effects of Neurotoxic and Biorational pesticides on reproductive parameters and ovarian development of Chrysoperla externa adults (Neuroptera: Chrysopidae).

HAROMBOURE MARINA; FRANCESENA NATALIA; ALZOGARAY RAÚL; SCHNEIDER MARCELA INES

Ghent

Simposio; 67 th International Symposium on Crop Protection.; 2015

Universiteit Ghent

Compatibility between natural enemies (NE) and selective pesticides is a strategy for pest controlin the framework of Integrated Pest Management (IPM). Several experiments of lethal and sublethal effects of pesticides on NE are carrying out that give the knowledge for implement these programs. An efficient NE should have a wide geographic distribution and feed on a broad range ofprey, among other caracteristics. Chrysoperla externa Hagen is a Neotropical predator with a distribution from the Antilles to the Patagonia region in Argentina. Its three larval instars feed on soft-body arthropods with economic importance, such as aphids, thrips, lepidopteran larvae,whiteflies and acarii. C. externa has been reported as part of the entomofauna of the HorticulturalRegion of La Plata (Buenos Aires province) feeding on important horticultural pests. Adults feed on pollen and nectar from the crops or spontaneous nearby, and therefore they are exposed to pesticides. For this reason, the objective of the present work was to evaluate lethal and sublethal effects of different insecticides commonly used in this region on C. externa adults by ingestionexposure. Four insecticides with different modes of action were evaluated at their maximum recommended concentrations for their use in the field: cypermethrin 25 mg/l i.a. (Glextrin 25%),acetamiprid 200 mg/l i.a. (Mospilan 20%), pyriproxyfen 75 mg/l i.a. (Epingle 10%) and azadirachtin 40 mg/l i.a. (Neem-Azal 1,2%). Adults of less than 24 h of emerged were exposed to insecticides by ingestion through aqueous solutions during 72 h. Distilled water was used as solvent. Controls were exposed to solvent alone. After 72 h from insecticides exposition, individuals were sexed according to their external genitalia and were paired. The toxicity end-points were: mortality, andfecundity and fertility of the surviving females during 7 days. Dissections of the treated females were done, ovaries were removed and observed under binocular microscope in order to record ovarian anomalies, and relate potential effects of the insecticides on reproduction. The 100% of individuals exposed to acetamiprid died during the 24 h after treatment. The remaining treatments did not affect the adult survival. At long term, fecundity and fertility were reduced by azadirachtin and this effect was corroborated with the ovaries dissections, showing ovarian anomalies. Cypermethrin and pyriproxyfen did not show any variation in the survival and reproduction with respect to control. Our studies reflect that C. externa adults are susceptible to acetamiprid and azadirachtin and corroborate the importance of toxicity studies of pesticides on all developmentalstages of a determined NE.