Influence of thiacloprid and spirodiclofen on survival and fecundity of predatory miteTyphlodromus pyri Scheut. (Phytoseiidae)

Abstract: The influence of thiacloprid and spirodiclofen on survival and reproduction of thepredatory mite Typhlodromus pyri (Phytoseiidae) was studied under laboratory conditions onnatural substrate. Methods included effects by direct sprays of the test organisms and residualtoxicity by contact with a treated surface during one week. Effects of thiacloprid and spirodiclofenwere estimated on basis of lethal effects (survival rate) and sublethal effects (eggs laid and hatchingrate).Corrected mortality with thiacloprid and spirodiclofen reached 61.3% and 33.3%, respectively.Both results were significantly different to control and thiacloprid mortality was significantly higherthan spirodiclofen. Egg production and hatched larvae and nymphs by leaves were reduced withboth products but as these reductions were more or less proportional to the mortalities, direct effectson reproduction were not observed with both test products.Results indicated that spirodiclofen had limited effects on T. pyri and could be used in IPMprogrammes. Thiacloprid was more toxic in the laboratory on natural substrates and shouldpreferably be tested in more realistic conditions before being recommended or not in IPM.