Effect of Beauveria bassiana and Metarhizium anisopliae (Deuteromycetes) upon the coffee berry borer (Coleoptera : Scolytidae) under field conditions

The effect of three strains of the fungus Beauveria bassiana (Balsamo) Vuil lemin and two strains of Metarhizium anisopliae (Metschnikoff) Sorokin upon the coffee berry borer, Hypothenemus hampei (Ferrari),was studied in three coffee farms at different altitudes (450-1,100 m above sealevel) in Soconu sco, Chiapas, Mexico. The maximum average percentage mycosis varied accordi ng to altitude. At 450 m asl (El Rincon) mycosis was 14.3% for B. bassiana and 6.3% for M. anisopliae; at 880 m asl (Santa Anita) mycosis was 40.6% fo r B. bassiana and 12.6% for M. anisopliae, and at 1,100 m asl (Alpujarras) 33.9% for B. bassiana and 22.1% for M. anisopliae. The effect of fungal myc osis through time was not significant (P > 0.01) in any of the farms, but t here was a significant difference between the strains of the fungus (P < 0. 01); the best strains being Bb25 and Ma4 at the lower altitude, Bb26 and Ma 4 for the middle altitude and Bb26 and Ma4: at the higher altitude. Environ mental factors such as temperature, relative humidity and rain were not cor related with the percentage mycosis caused by B. bassiana and M. anisopliae . However, in the case of B. bassiana there was a significant, positive cor relation (P < 0.01) between the infestation levels of the pest and the myco sis response of the entomopathogen.