Population Density of the Important Harmful Mites and Their Predatories in the Walnut Orchards of Around Van Lake

Abstract

The aim of this study was to determine the population densities of pest and important predatory mites in the walnut orchards of around Van Lake. The study was conducted in five walnut orchards in the Adilcevaz county in Bitlis (three orchards) and Gevas county in Van (two orchards), during the growing seasons of 2005-2006. Surveys were carried out in every week from May to November. The results of study indicated that the population densities of mites began to increase generally in early July, reached the maximum level at late July and at early August and preserved to late October. In this period, the population densities of Aceria erinea Nalepa (Acari: Eriophyidae) and Eotetranychus carpini (Oudemans) (Acari: Tetranychidae) were determined as 51.9 galls/leaf and 304.1 mites/leaf, respectively. Euseius finlandicus (Oudemans) (Acari: Phytoseiidae) was the most effective predatory mite on E. carpini and A. erinea and it was observed that its population reached to 4.5 mites/leaf. In the sprayed orchard, E. finlandicus population was not enough for controlling mites and the population densities remained at very low levels.