Interactions among populations of predatory mites and insect and mite pests on olive trees in Turkey

Abstract

This study was conducted to determine the population fluctuations and interactions between predatory mites and pests on leaves, shoots, and flower buds of olive trees. Studies were carried out at weekly intervals in four unsprayed olive orchards at Bursa (Turkey), which were located in different ecological areas, during 2007 and 2008. Population fluctuations of predators and pests were monitored by counting individuals on ten 25-cm long shoots collected at different heights from 10 trees in each olive orchard. The mites and mobile small insects were extracted in Berlese funnels and then examined under a stereomicroscope. In this study, the most common pest species found were: Brevipalpus oleae, Aceria oleae, Thrips tabaci, Liothrips oleae, Parlatoria oleae and Saissetia oleae. Although several mite predators, representing the families Phytoseiidae, Erythraeidae, Cheyletidae and Stigmaeidae, were found, members of the family Phytoseiidae dominated. Among the phytoseiid species, Typhlodromus (Typhlodromus) athiasae and Typhlodromus (Anthoseius) recki were found more often, whereas T. (A.) involutus was rarely encountered. Observations conducted at Bursa during the 2 years suggested that in these olive orchards the phytoseiids exist in a clear numerical response to pest species such as B. oleae and the thrips species. In addition, the results indicated that the large phytoseiid populations were a response to the secretions of the scale insects.