Abstract

RUIZ-SANCHEZ, Esaú et al. In vitro growth, sporulation and germination of five strains of Metarhizium and their virulence on Bemisia tabaci eggs and nymphs. Rev. Mex. Mic [online]. 2011, vol.33, pp.9-15. ISSN 0187-3180.

In vitro growth, sporulation and germination of four wild and one commercial strains of Metarhizium and their virulence on Bemisia tabaci eggs and second instar nymphs under laboratory and greenhouse conditions were evaluated. The radial growth of the colony was significantly lower for MaSin strain (0.30 cm/day). The sporulation was significantly higher in MaSin (8.5x10⁶ conidia/ml) and MaCol strains (6x10⁶ conidia/ml). The conidial germination was not significantly different between the strains evaluated. The virulence of the Metarhizium strains on B. tabaci was evaluated by immersion of leaves that contained eggs or nymphs in conidial suspension (1 x 10⁷ conidia/ml). There was no significant difference on mortality of eggs under laboratory (9.9-32.2%) or greenhouse (18.7-30.7%) conditions by the effects of the Metarhizium isolates. There was no difference either on mortality of nymphs (67.7-88.2%) by the effects of the strains in laboratory conditions. However, in greenhouse conditions, MaSan and MaCol strains caused significantly higher mortality, with values of 60 y 50.5%, respectively. These results indicated that all strains are more virulent for nymphs than for eggs of B. tabaci. MaSan and MaCol strains could be potential candidates for the management of B. tabaci.

Keywords : biological control; entomophatogenic fungi; whitefly.

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