Effects of Beauveria bassiana and Metarhizium anisopliae on mortality, fecundity and egg fertility of Tetranychus evansi

• Published in: Journal of applied entomology (1986) 2006-04, Vol.130 (3), p.155-159
• Main Authors: Wekesa, V.W, Knapp, M, Maniania, N.K, Boga, H.I
• Format: Article
• Language: English
• Subjects: application rate; Beauveria bassiana; Biological and medical sciences; Biological control; conidia; Control; developmental stages; dose response; egg fertility; egg hatchability; entomopathogenic fungi; fecundity; Fundamental and applied biological sciences. Psychology; Metarhizium anisopliae; mite control; mortality; Phytopathology. Animal pests. Plant and forest protection; Protozoa. Invertebrates; Tetranychidae; Tetranychus; Tetranychus evansi
• ISSN: 0931-2048; 1439-0418
• DOI: 10.1111/j.1439-0418.2006.01043.x

The susceptibility of various developmental stages of Tetranychus evansi Baker & Pritchard (eggs, larvae, protonymphs, deutonymphs and adults) to the entomopathogenic fungi Metarhizium anisopliae (Metschnikoff) Sorokin and Beauveria bassiana (Balsamo) Vuillemin was evaluated under laboratory conditions. Three concentrations (3.0 [multiplication] 10⁶, 1.0 [multiplication] 10⁷ and 1.0 [multiplication] 10⁸ conidia/ml) of both fungi were used for each stage. The effect of fungal infection on fecundity and egg fertility was also investigated using both fungal species. Deutonymphs that survived the infection and developed into adult females were allowed to oviposit. Adults and deutonymphs were more susceptible to fungal infection than larval and protonymphal stages at all the concentrations. Nevertheless, the concentration level influenced the mortality of the different mite stages. Eggs were also susceptible to fungal infection and mortality was dose-dependent. Fungus-treated female mites laid fewer eggs than the controls but there was no significant difference in egg hatchability between the treatments.