Epidemiology ofBeauveria bassianain Controlled Populations ofBactericera cockerelli

Abstract

The effect of four variables -- ratio of infected/healthy individuals, sex, interference from healthy males, and transmission time — was evaluated to know the potential of horizontal transmission of Beauveria bassiana (Balsamo) Vuillemin strain Bb-M to induce epizootics in controlled populations of tomato/potato psyllid, Bactericera cockerelli (Sulc). In addition, the time in which 50% of the conidia germinated (GT50) and response to humidity were evaluated. The Bb-M strain required high humidity to sporulate (≥ 93%) and had a GT50 of 12.7 hours. The proportion of infected/healthy insects was very correlated (r = 0.804, p ≤ 0.05) with dissemination of the entomopathogen, suggesting a larger number of infected insects increased the spread of the entomopathogen. The sex effect was not consistent in transmission of the entomopathogen, with tendency toward greater infection (94%) when only males were infected. Transmission by males fluctuated from 15 to 96.66%, with greatest transmission having a ratio of 1:10 (infected males:healthy females). The mean transmission time (Tt50) was 5.8 days. The results showed the evaluated strain by the auto-dissemination technique has potential for use in management of tomato psyllid; however, future studies are needed to design and evaluate strategies for application in the field.