author(s)
Fazal Maula, Imtiaz Ali Khan

abstract
Two Spotted Spider Mite (TSSM), Tetranychus urticae Koch and European Red Mite (ERM), Panonychus ulmi Koch (Tetranychidae: Acarina) are major mite pests of applernorchards in Swat valley. For efficient control of pest mites on apple basic knowledge of developmental durations of pest is utmost important. In the present study developmental stages of TSSM and ERM were studied at two levels of temperature (24-26 °C) and (29-31 ^oC) and constant level of relative humidity 65+5% under laboratory conditions at Agricultural Research Institute, Mingora, Swat during 2010. The test arthropods were reared on fresh apple leaves. Variation in temperature significantly affected the developmental stages of both the male and female of the mite species. The total developmental duration of T. urticae female was 12.4 days at 24-26 ^oC and 10.0 days at 29-31 ^oC while for male it was 10.8 days at 24-26 ^oC and 8.3 days at 29-31 °C. The developmental duration of ERM female was 12.18 at 24-26 °C and 9.8 days at 29-31 ^oC while for male it was 11.61 days at 24-26 °C and 9.35 days at 29-31 °C. The developmental duration of females of both the species were longer than its males and it was longer for females and males of TSSM than of ERM. The present findings might be used in devising integrated pest management of TSSM and ERM on apple orchards in the Swat valley.