Use of Biological and Chemical Pesticides in Agricultural Production: What Fate for Entomopathogenic Fungi?

Abstract

In the context of integrated pest management, the compatibility between the products used and even with the natural enemies of crop pests should still be elucidated. In this study, interviews were done with about 60 coffee growers to assess the use of pesticides in the protection of coffee berries. Then, in vitro tests were used to evaluate the effects of extracts of the seed powders of Thevetia peruviana, Azadirachta indica, the chlorpyriphos-ethyl insecticide and the chlorothalonil + dimethomorph fungicide, on the development parameters of the entomopathogenic fungus Beauveria bassiana, the natural enemy of the coffee berry borer, Hypothenemus hampei. The said tests consisted of the method of poisoning the culture medium with pesticides, observation and counting of spores under the optical microscope. The analysis of the collected data showed that depending on the type and severity of the pest pressure, growers apply several types of mainly chemical pesticides. Among the pesticides tested, extracts of T. peruviana, A. indica and chlorpyriphos-ethyl considerably reduced the development of B. bassiana. These results show that in crop protection, the use of biological or chemical substances should be done in a judicious way, to ensure the conservation and the valorization of natural enemies of phytosanitary pressures.