One Metarhizium brunneum Strain, Two Uses to Control Ceratitis capitata (Diptera: Tephritidae)

We determined the virulence and insecticidal activity of the hypocrealean fungus Metarhizium brunneum (Petch) strain EAMb 09/01-Su and its crude extract against Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae) and we evaluated the combined use of the fungus with its crude extract. We also determined the effect of fermentation time, temperature, and initial pH of the M. brunneum culture medium on the insecticidal activity of the crude extract. When C. capitata adults were sprayed with a conidial suspension, the strain EAMb 09/01-Su caused 100% mortality with a mean lethal time (LT50) of 5.6 d and mean lethal concentration (LC50) of 2.84 x 10(7) conidia per milliliter. Fermentation time significantly affected the lethality of the crude extract when it was provided to C. capitata per os. The highest level of mortality (73.3%) and the shortest median survival time (25.5 h) was obtained from 15-d-old cultures. The crude extract was demonstrated to be thermostable, given that the mortality was >50% at 48 h when the extract had been heated to 100 degrees C for 3 h. Lastly, the optimum initial pH for maximum crude extract activity in terms of mortality ranged between 7 and 9. Additivity was observed for all M. brunneum EAMb 09/01-Su strain crude extract combinations tested, indicating compatibility between products. We concluded that the M. brunneum EAMb 09/01-Su strain is a promising tool for medfly control alone or in combination with its crude extract.