spider mite Tetranychus urticae Koch. Pathogenicity of the two fungi against T. urticae were studied and evaluated under
laboratory and semi-field conditions. Three fungal spore suspensions were prepared; T. harzianum (2x106 spores/ml),
C. herbarium (1x106 spores/ml) and a mixture of both fungi (50%: 50%). The effect of fungal spore suspensions on the
deferent stages of T. urticae was studied at 30 & 35oC and 90 % R.H. The mortality percentages of all mite stages
increased with prolonging the period after spraying. The mixture of the two fungi gave higher mortality than a single one
after 3 and 7 days for all mite stages reaching 46.8% and 59.8% after 3 and 7 days respectively at 30oC, while at 35oC, it
increased to 65.1% and 83.0%after the two periods respectively. Under semi-field conditions, the mean reduction in mite
population resulted from using suspensions of T. harzianum and C. herbarium recorded 42.4 and 43.9% respectively
after 10 days of spraying, while it increased to 58.2% when using the mixture of the two fungi. Both fungi T. harzianum
and C. herbarium exhibited a positive effect in the pathogenicity of the two-spotted spider mite, T. urticae, but it is
recommended to use a mixture of both fungi to obtain more efficient control.