Actividad insecticida y persistencia de un formulado a base de Beauveria bassiana para el control de Diatraea saccharalis

The development and use of microbial pesticides for the control of agricultural pests has intensified in recent years due to the increasing need for reductions in the use of highly toxic agrochemicals. To fill this growing need for biopesticides it is necessary to develop suitable formulations that stabilize microorganisms against environmental stress factors that reduce their efficacy and persistence in the field. In this context, the objective of the present work was to determine the insecticidal activity and persistence on sugarcane plants, of an emulsifiable concentrate (EC) containing Beauveria bassiana for the control of sugarcane borer, Diatraea sp. Photostability of the formulation under UV radiation type B and the mean and ninety lethal concentrations were also determined under laboratory conditions. The EC reached more than 80% efficacy against D. saccharalis larvae under semi-controlled field conditions. The EC efficiently photostabilized the conidia, maintaining 68.9% germination after nine minutes of irradiation while unformulated conidia completely lost the ability to germinate. This effect was also observed for the insecticidal activity, with unformulated conidia losing 30% more efficacy than formulated conidia after nine minutes of irradiation. The insecticidal activity and conidia count on sugarcane plants under field conditions decreased one and two weeks post application, respectively. Although the EC containing on B. bassiana demonstrated effective insecticidal activity against D. saccharalis, it is necessary to carry out field trials to optimize the formulation and determine the method and frequency of application to maximize its performance.