Drying and formulation of blastospores of Paecilomyces fumosoroseus (Hyphomycetes) produced in two different liquid media

Formulation matrices can play an important role in improving the storage su rvival and biocontrol efficacy of microorganisms used for the control of pe st insects. In this study, liquid culture-produced blastospores of the ento mopathogenic fungus Paecilomyces fumosoroseus were formulated with differen t inert and organic materials prior to air-drying. Paecilomyces fumosoroseu s blastospores were produced in two different liquid media, a basal salts m edium supplemented with Casamino acids and glucose (LM1) and a medium conta ining peptone of collagen and glucose (LM2). Blastospores produced in the t wo test media were formulated with various supports. The formulation suppor ts were cornstarch, rice flour, talc powders, Mexican lime, calcined kaolin clay, and diatomaceous earth. Several of the supports were tested at diffe rent concentrations. The initial and long-term (after storage at 4 and 28 d egreesC) survival of the formulated, air-dried blastospores were evaluated. Initial blastospore viabilities were affected by the formulation material and by the blastospore production medium. Medium composition, drying suppor t and storage temperature had an impact on the long-term survival of the bl astospores. Under the conditions of the study, LM1 produced higher concentr ations of blastospores that not only survived drying better than blastospor es produced in LM2 but also maintained viability longer during storage in t he formulation supports tested. The nature of the drying supports was shown to have a significant impact on the storage stability of all blastospores, particularly those produced in LM1. Under the production, drying and stora ge conditions used in the study, calcined kaolin clay formulations stored a t 4 degreesC had the best storage stability. In all formulations tested, sp ore survival over time was reduced for blastospore formulations stored at 2 8 degreesC rather than 4 degreesC.