Production and processing of Metarhizium anisopliae var. acridum submerged conidia for locust and grasshopper control

Currently, mycopesticide development for locust and grasshopper control depends on aerial conidia or submerged spores of entomopathogenic fungi. In Our Study, the production of submerged conidia of Metarhizium anisopliae var. acridum (IMI 330189) was investigated in a liquid medium containing 3% biomalt and 1% yeast extract (BH-medium). The effects of freeze and spray drying techniques Oil the quality of submerged conidia were determined. The influence of different additives on the viability of fresh Submerged conidia and their suitability for oil flowable concentrate formulation development was assessed. In a BH medium maintained at 180 rev min(-1), at 30 degreesC for 72 h, IMI 330189 produced a green pigmented biomass Of Submerged conidia whereas in Adamek medium it produced a yellowish biomass of submerged spores. The spore concentration was high in both media; however, the size of the spores produced in the BH medium was significantly lower than those produced in Adamek medium (P<0.001). Submerged conidia can be effectively dried using either freeze or spray drying techniques. The viability and speed of germination were significantly affected by the drying and pulverizing process (P<0.001). The initial viability was significantly higher for spray-dried Submerged conidia than for freeze-dried spores. pulverizing of freeze-dried Submerged conidia reduced the speed of germination and the viability by 63-95%. Dried Submerged conidia can be stored over 45 wk at low temperatures (<10degrees) Without suffering a significant loss in viability. Furthermore, we have identified carriers that Lire suitable for oil flowable concentrate formulation development.