Two new acaricides, pyridaben and fenpyroximate: evaluation of their efficacy on Panonychus ulmi (Koch) and Aculus schlechtendali (Nal.) and their nontarget effects on beneficial arthropods.
The efficacy of 2 new acaricides, pyridaben and fenpyroximate, was evaluated in an apple orchard (cv. Golden Delicious) in Trentino, Italy, in 1991-92. The acaricides were very effective against the tetranychid Panonychus ulmi, but less effective against the eriophyid Aculus schlechtendali. Both acaricides had a negative effect on the predatory phytoseiid Amblyseius andersoni in laboratory tests and in the field. The nontarget effects of pyridaben on beneficial arthropods in pear orchards (cv. Kaiser) was also examined. Its toxicity varied depending on the species and life stage exposed; pyridaben was toxic to young instars of the anthocorid Anthocoris nemoralis, moderately toxic to the trombidiid Allothrombium fuliginosum and had a low toxicity against adult anthocorids, species of chalcid parasitoids and spiders [Araneae].