Seasonal population dynamics of Typhlodromus pyri Scheuten (Acari, Phytoseiidae) in apple orchards in the region Meckenheim

Abstract

Typhlodromus pyri Scheuten (Acari, Phytoseiidae) has been reported as the most important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture. However, biological data on T. pyri was insufficient on important parameters like seasonal population dynamics and within-tree and on-leaf distribution in apple orchards in the region of Meckenheim, Germany. The purpose of the present work was, therefore, to obtain experimental data on these parameters of T. pyri from 2000 to 2002 in the apple orchards in this region. The results showed that overwintered females of T. pyri reactivate and start laying eggs between late March and early April. The mean daily number of the different stages of T. pyri per leaf peaked in July each year, where it ranged between 0.92-1.68 eggs, 0.81-1.41 nymphs, 0.64-1.32 females and 0.37-0.52 males. A significantly higher number of T. pyri individuals congregated in the bottom layer of trees (0.34-0.64 individuals/leaf) than in the middle and top layers (0.23-0.38 and 0.12-0.23 individuals/leaf, respectively). We found that 91.4-94.1% of the total eggs, 89.6-91.7% larvae, 73.0-76.5% nymphs, 60.5-64.6% adult females and 52.6-55.9% adult males concentrated their activities in the inner area of the leaf surface. More than 50% of the predatory mites congregated in the bottom layer in winter. Mean total density of the over-

Population density of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) on various pear cultivars in organic and integrated orchards

“…The influence of host plant phenology was confirmed also by our experiments in both years, because we observed the highest population density of T. pyri in the autumn cultivar Conference. In our experiments we recorded the highest number of T. pyri individuals in the first half of August 2009 and in the second half of August 2010, while Khan & Fent (2005) found the highest number of T. pyri individuals on the leaves of an apple-tree in the Meckenheim area in July. The population density of T. pyri was different also in particular orchards.…”