A laboratory investigation on virulence of Metarhizium anisopliae on Thrips tabaci (Thys.: Thripidae) and its predator, Orius albidipennis (Hem.: Anthocoridae)

Abstract

In the present study, virulence of three isolates of Metarhizium anisopliae (Ascomycota, Clavicipitaceae) were evaluated on the second instar larvae of the onion thrips, Thrips tabaci Lindman by using spray potter tower at six conidial concentrations of isolates (103-108 conidia/ml) with Thrips Entomopathogenic Bioassay System (TEBS) method. Causing the highest total mortality rate on thrips larvae and having the lowest LC50 value (2.3 × 104 conidia/ml), M. anisopliae EUT118 was selected as the highest virulent isolate. Afterwards, the susceptibility of female adults and 5th nymphs of Orius albidipennis (Reuter) was tested against this isolate of M. anisopliae without attendance of host. Results indicated that two stages of predator; female adults and 5th instar nymphs had similarly low susceptibilities to fungal infection. In general, our results revealed that the anthocorid predator, O. albidipennis was less affected by this isolate of fungus. As a result, these two biocontrol agents could be used both together in control programs of T. tabaci in greenhouses.

Keywords

• thrips tabaci
• orius albidipennis
• metarhizium anisopliae
• biological control