Desenvolvimento do fungo Beauveria bassiana exposto à bactéria Bacillus pumilus

Abstract

Species of entomopathogenic fungi belonging to the genus Beauveria are among the most frequently found on dead insects in the natural environment. B. bassiana is the most studied species as a biological control agent for pests in several crops of economic interest. This species, during pest management, can come into contact with other phytosanitary products used in crops. Among the antagonistic microorganisms is the bacterium Baccilus pumilis, whose mode of action is to inhibit the development of the pathogen on the leaf surface, in addition to activating the plant's defense system. Thus, the objective of this work was to evaluate the effect of the microbiological fungicide based on Bacillus pumilus, on the vegetative growth and production of conidia of B. bassiana (IBCB 66). Different doses of commercial product based on B. pumilus (100, 400 and 800 mL.ha-1) were mixed with the liquefied culture medium and this was poured into Petri dishes. After solidification, the fungus was inoculated at three equidistant points and the plates incubated for 7 days in a BOD-type climatic chamber at 25 ± 1 ºC, 12-hour photophase and relative humidity of 70 ± 10%. At the end of the incubation period, the average diameter of colonies produced and the number of conidia produced were evaluated. It was verified that there was no effect of the different doses of the biofungicide tested on the evaluated parameters. The results suggest the possibility of joint use of these microorganisms, when necessary, without impairing the performance of the entomopathogenic fungus.