Pathogenicity of the Fungus Beauveria bassiana and Cladosporium sp. on Different Life Stages of the Two Spotted Spider Mite, Tetranychus urticae Koch Under Laboratory Conditions

Shaabow, A. and A. Haj Hassan. 2023. Pathogenicity of the Fungus Beauveria bassiana and Cladosporium sp. on Different Life Stages of the Two Spotted Spider Mite, Tetranychus urticae Koch Under Laboratory Conditions. Arab Journal of Plant Protection, 41(3): 314-320. https://doi.org/10.22268/AJPP-41.3.314320 This study was carried out in the entomology laboratory of the Agricultural Scientific Research Center in Lattakia, Syria, to evaluate and compare the effect of local isolates of the entomopathogenic fungus Beauveria bassiana and two isolates of the fungus Cladosporium spp. on different life stages of the two-spotted spider mite Tetranychus urticae during October 2021.Conidial suspension for each fungal isolate were applied at a concentration of 1×107 conidia/ml, on the different stages of mites (adults, nymphs, eggs), using the direct spraying method. The effects of each isolate were significantly different between stages. The results obtained showed that the most affected stage was the adults stage, with a death rate of 100% when treated with B. bassiana isolate, whereas it reached 72.5 and 58.5% when the two isolates of Cladosporium sp. were used. The egg stage was less sensitive to infection with fungi, where the death rate reached 59% for one of the two isolates of Cladosporium sp., 45.13% for the second isolate and 38.25% for the B. bassiana isolate. The half lethal time (LT50) was 3.82 days for the B. bassiana isolate on the adults stage, whereas isolate 2 of Cladosporium spp. was more effective on nymph and egg stages, with LT50 reached 7.77 and 8.68 days, respectively. Keywords: Tetranychus urticae, biological control, Beauveria bassiana, Cladosporium spp