Biological quality of Beauveria bassiana formulations used for control of the coffee berry borer

Abstract

For commercialization of entomopathogenic fungal formulations, the control of biological, physical, and chemical properties are necessary to assure the consumer a product of maximum field efficacy. This study summarizes the results of the analysis of quality variables such as spore concentration per gram, germination percentage (24 h), mortality percentage and average mortality time (days) of the coffee berry borer, of different Beauveria bassiana formulations evaluated between 1993-1998. Averages values were determined based upon the total number of samples of each product evaluated during the six years period. The highest spore concentration of B. bassiana was found in Conidia WG® (4,4xIO'ºe/g), followed by freeze dry Brocaril® (4.3xl010e/g). The latter also presented the highest germination (95±5,4) followed by the Cenicafé strain (86±5,6). The greater percentage of mortality caused to freeze-dry Brocaril® (92±10) in a time average of 4,5±0,8 days, and the Cenicafé strain (81 ± 13) in 4, 7±0,8 days. The Bb9205 isolation reactivated in berry borer, multiplied in rice with 30 days of development was used as a reference, presented the following averages: concentration of 1,9xl010e/g, germination 90±8.1 %, mortality 90±8.6% in 4, 7± 1,0 days. The results showed a high variability throughout the time especially in spore concentration; this variable this related to factors involved in the process of production like substrate, storage, temperature, and humidity. The improvement of these limiting conditions has led to higher formulations quality in recent years.