Pathogenicity of Two Fungi; Trichoderma harzianum and Cladosporium herbarium on The Two-spotted SpiderMite; Tetranychus urticae Koch

Abstract

Two fungi; Trichoderma harzianum and Cladosporium herbarium were isolated from dead bodies of the two-spotted 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 (2x10 6 spores/ml), C. herbarium (1x10 6 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 & 35 o C 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 30 o C, while at 35 o C, 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.