Testing the Pathogenicity of Metarhizium anisopliae Against Tetranychus urticae Adults Under Laboratory Conditions

Abstract

Laboratory studies were conducted to evaluate the pathogenicity of three isolates of the pathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin (M1, M2 and M3) to the adults of the two-spotted spider mite Tetranychus urticae Koch, in addition to their effect on the longevity of the adult females. Results obtained showed high efficacy of the three isolates in killing the spider mite adults, as the mortality rate 10 days after treatment reached 91.32, 75.89, and 56.25% for isolates M1, M2 and M3, respectively. The half lethal time (LT₅₀) attained was 4.3, 6.0, and 6.4 days for isolates M1, M2, and M3, respectively. The effect of the fungus on mite females’ longevity was evident, and the isolate M1 was the most effective in reducing adult female longevity, as the average longevity rate was 5.3 days, followed by M2 (6.4 days) and M3 (7.475 days), compared to the control treatment (13.875 days).

Keywords:

Entomopathogenic fungi, the two-spotted spider mite, Tetranychus urticae, Metarhizium anisopliae, pathogenicity.