Microesclerotia production of Purpureocillium lilacinum in three different media.

The use of the resistant propagules, termed microsclerotia (MS), produced by the nematophagous fungus Purpureocillium lilacinum stands out as an eco-friendly tool for the control of various soil-inhabitant pests. The present study aimed to screen 36 isolates of P. lilacinum from the ESALQ collection of microorganisms for maximum MS production. Three culture media were tested varying Carbon:Nitrogen ratio corresponding to 10:1 for medium named J4 and 50:1 for both media J6 and A1. All liquid cultures were cultivated in baffled flasks (250 mL) containing 45 mL of each medium inoculated with 5 mL of spore suspension. The flasks were maintained on a rotary incubator shaker (300 rpm at 28 ± 2°C) for 96h. Concentrations of MS greatly varied among all isolates, where yields reached up to 6x104 MS.mL-1 for J6, 1-2x104 MS.mL-1 for J4 and A1. Therefore, there is a strong evidence that higher Carbon:Nitrogen ratio promotes greater numbers of MS for isolates of P. lilacinum. Media optimization and bioefficacy tests against nematodes and arthropod pest are underway with the bests P. lilacinum MS producers.