Whey for mass production of Beauveria bassiana and Metarhizium anisopliae Adane KASSA a, *, Michael BROWNBRIDGE b , Bruce L. PARKER a , Margaret SKINNER a , Vladimir GOULI a , Svetlana GOULI a , Mingruo GUO c , Frank LEE c , Teri HATA a a University of Vermont, Entomology Research Laboratory, 661 Spear Street, Burlington, VT 05405-0105, USA b AgResearch Limited, Agriculture and Science Centre, Gerald Street, PO Box 60, Lincoln, New Zealand c University of Vermont, Department of Nutrition and Food Science, 351 Marsh Life Science Building, Burlington, VT 05405, USA article info Article history: Received 8 June 2007 Received in revised form 29 November 2007 Accepted 10 December 2007 Corresponding Editor: Richard A. Humber Keywords: Conidia Entomopathogenic fungi High lactose Submerged spores Whey permeate abstract Spore production of Beauveria bassiana and Metarhizium anisopliae was studied in a novel whey-based culture media. Spore yield and viability were determined for two B. bassiana (GHA-726 and CA-603) and two M. anisopliae (CA-1 and IMI 330189) isolates following production in three whey-based systems: solid, liquid, and a diphasic production system. Our study indicated that whey permeate can be used effectively for production of spores of entomopathogenic fungi. However, spore yield and viability were significantly influ- enced by fungal isolate, whey concentration, and the type of production process used. Under the conditions defined in the present study, spore yields ranging from 1.3  10 9 – 10  10 11 spores l 1 of whey medium could be obtained depending on the strain and pro- duction process used. Our study revealed that spores produced by all strains in whey-based solid and liquid media showed between 73–99 % viability; germination rates were compa- rable with those obtained using the standard SDA medium. In the two-stage production process, the viabilities of conidia produced by GHA-726, CA-603, and CA-1 were 35–86, 32–98, and 6–29 %, respectively; viability was correlated with whey concentration and iso- lates. Whey permeate can be used as a growth substrate for mass production of biocontrol fungi. We hypothesize that spore yield and viability could be improved by careful selection of whey content in the medium, incorporation of critical additives and optimization of culture conditions. Published by Elsevier Ltd on behalf of The British Mycological Society. Introduction Entomopathogenic fungi are ideal candidates for integrated pest management (IPM) in forests and greenhouses (Kaya & Lacey 2000). They have a limited host range, with minimal impact on non-target species. Mass production and formula- tion processes directly influence the cost, shelf life, virulence, and field efficacy of fungal products. Production processes for fungal biopesticides must be low-cost and yield high concentrations of viable, virulent, and persistent propagules (Jackson 1997). Production and formulation technologies have been developed for aerial conidia and submerged spores of entomo- pathogenic fungi (Burges 1998; Butt & Brownbridge 2001; Deshpande 1999). The type of process used depends on the fungal strain, target pest, environment, formulation and application strategies, desired end product, and the market (Deshpande 1999; Jackson 1997). The nutritional composition * Corresponding author. E-mail address: akassa@uvm.edu journal homepage: www.elsevier.com/locate/mycres mycological research 112 (2008) 583–591 0953-7562/$ – see front matter Published by Elsevier Ltd on behalf of The British Mycological Society. doi:10.1016/j.mycres.2007.12.004