CONIDIA PRODUCTION OF THE FUNGUS BEAUVERIA-BRONGNIARTII ON BARLEY AND QUALITY EVALUATION DURING STORAGE AT 2-DEGREES-C

Strains of Beauveria brongniartii were cultivated on whole grains of barley. The yield of conidia depended mainly on the addition of water and the length of incubation. Two attempts of mass production in polyamid bags were carried out: (1) with a low yield of 3.24 × 106 conidia/g barley after 14 days of incubation and (2) with a high yield of 1 × 108 to 2 × 109 conidia/g after 24-42 days, both at 23°C. During storage at 2°C for 24 months, the number of viable conidia decreased due to germination and natural loss of viability. Spore production as well as the rate of loss in viability varied between the strains. As the fungus continued to grow at the storage temperature, the nutrient reserves of the medium decreased continuously. This led to a considerably reduced efficacy of the formulation in bioassays against white grubs (Melolontha melolontha L.). © 1992.