Observations on Population Levels of the European Red Mite (Acarina: Tetranychidae) and Associated Arthropod Predator Complexes in Different Spray Programs Over a 5-Year Period

Abstract

Selective and nonselective insecticide and fungicide treatments were applied in season-long programs in a Swiss apple orchard, for the control of arthropod and fungal pest complexes. The effects of these treatments on the European red mite, Panonychus ulmi (Koch), and its predators were studied over a period of 5 years. Abroad-spectrum compound, azinphos-methyl, gave good control of the codling moth, Cydia pomonella L., under a program of four to six sprays every 2 weeks per season. Equal or slightly inferior control was given by the more selective chemicals, chlordimeform and diflubenzuron. Fungicides used were either mite-suppressive or had no effect on mite predators. Effective P. ulmi predation was also enhanced by the use of selective acaricides and the combined effects of a predaceous mite, Amblyseius finlandicus (Oudemans), and a number of beneficial insects which became established in the blocks that received the selective insecticide treatments. These beneficial arthropods kept P. ulmi numbers below the damage threshold, demonstrating that integrated chemical and biological control of this pest is possible.