Release rates of typhlodromus athiasae porath and Swirski (Acari : Phytoseiidae)‎ to control the two-spotted spider mite Tetranychus urticae Koch (Acari : Tetranychidae)‎ on apple seedlings under greenhouse conditions

الملخص EN

A study was conducted at the Biological control studies and Research Centre -BCSRS (Damascus University /Syria) during 2013 – 2014.

The effectiveness of the predatory mite Typhlodromus athiasae Porath and Swirski (Acari: Phytoseiidae) as a suppressive agent of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), was evaluated on apple seedlings at release rates 1:10, 1:20 1:40 predator:prey and no predaceous mites serving as control under greenhouse conditions.

The ratio of 1:10 predator:prey reduced T.

urticae populations significantly after one week of release with the highest density of T.

athiasae occurring in 6th week, and kept them at low levels thereafter.

The highest mean numbers of T.

urticae were found in the 5th week at ratios 1:10, 1:40 predator:prey and in the 4th week at 1:20 predator:prey.

This study demonstrates the potential of T.

athiasae to effectively control T.

urticae on apple seedlings under greenhouse conditions at predator:prey ratio of 1:10.

However, T.

athiasae was unable to control the T.

urticae populations when the predator:prey ratio reduced to 1:40.