A Study of some Methods for Apple spider mites Population Management in As- Suwayda Governorate- Southern Syria

Some management methods of spider mite population were studied on apple trees dur-ing the period 2018-2021 at different elevation in Southern Syria-. As- Suwayda Governorate. Population dynamics of phytophagous mite Tetranychus urticae Koch (Acari: Tetranychidae), Panonychus ulmi Koch (Acari: Tetranychidae) and Phytosei-ids were studied on Golden Delicious and Starking Delicious apple varieties. Different densities of spider mites on the two varieties were observed, The Phytosiieds (Typh-lodromus (Typhlodromus) pyri Scheuten و Typhlodromus (Typhlodromus) cotoneastr Wainstein) population density was higher on Starking Delicious. Sustibility of eight apple varieties towards the two studied spider mite species showed significant differences of infection among varieties, which correlated to the content of apple leaves of main nu-trition (N P K). Principal component analysis (PCA) showed positive correlation to P. ulmi with apple-leaf contents of potassium and showed positive correlation to T. urticae with ni-trogen and phosphor.The most susceptible varieties to P. ulmi were Top Red, Starking Deli-cious and Starking Red Delicious, and the most susceptible varieties to T. urticae were Golden Delicious, Golden 972 and Granny Smith. The results revealed no significant ef-fect of basal application of fertilizers, except in case of potassium sulphate, on the number of the two species; whereas foliar treatment had variable effects on both spe-cies, it decreased the numbers of T. urticae and increased the numbers of P. ulmi. Nitrogen and phosphour had positive effectson T. urticae. Field application of horticulture oils on both apple varieties proved efficacy in reducing numbers of both mite species wheth-er during dormant or growth seasons. The negative impact of summer oil on Phytosei-ids mites was more notable than it of dormant oil. The effect of botanical bio-pesticide on all development stages of T. urticae and P. ulmi was studied under lab and fieldconditions. The study demonstrated that herbomite and nimbecidine1% EC were ef-fective control pesticides,the number of mobile stages reached 1.5/leaf comparing with 5.1 /leaf in control, thus it can be used in IPM programs. The effect of several acaricids of different mode of action groups were evaluated under in lab and field conditions (Cyflumetofen, Hexythiazox10%, Abamectin 1.8%, Spirodiclofen24%). They showed different efficiency. Activity of Spirodiclofen24% on eggs reached 100% after15 days of treatment and 96.01% in Cyflumetofen treatment and 100% on mobile stages in both acaricids. Mixing some acaricids with summer oil led to long lasting affect com-pared to other treatment.