Effect of the entomopathogenic fungi on mortality and injury level of western flower thrips,<i>Frankliniella occidentalis</i>

Abstract The harmfulness of western flower thrips, Frankliniella occidentalis, including insect mortality and plant injury level after the application of three productive and active strains of the entomopathogenic fungi, Metarhizium anisopliae, Lecanicillium lecanii, and Beauveria bassiana, was estimated. LC50 of the M. anisopliae for second instar larvae was twice that of L. lecanii and 1.7 times higher than that of B. bassiana. The average number of damage zones on leaf surfaces after the application of fungi (5×106 spores per ml) constituted 3.0 ± 0.7, 15.9 ± 4.6, and 22.4 ± 4.3 per leaf, respectively (control 67.0 ± 5.7). The total damage area of the leaves was 2.2 ± 0.4, 5.2 ± 0.9, and 4.5 ± 0.6% (control 13.7 ± 3.0%), respectively. Fungi B. bassiana and L. lecanii showed the same level of insect mortality but the number of damage zones and the total damage areas had significant differences. The most effective fungus was found to be M. anisopliae which provided higher plant protection as measured by the decrease in plant injury.