Mass Production, Yield, Quality, Formulation and Efficacy of Entomopathogenic Metarhizium anisopliae Conidia

Aims: The aim of this study was to develop an easy but robust method for mass production, to formulate and compare the efficacy of mass produced conidia of a local isolate Metarhizium anisopliae against aphids and oil-formulated conidia against whiteflies.
Study Design: The randomized complete block design with replications.
Place and Duration of Study: 2012-2014, Laboratory of Crop Protection Department, Faculty of Agricultural Engineering and Veterinary Medicine, Lebanese University.
Methodology: Isolate of fungal entomopathogen M. anisopliae (Metschn.) Sorokin (LIM1) was grown on cooked rice, wheat, vegetable peels and burgul in roasting bags to produce and harvest spore powder. The cultures were dried and total yield of harvested conidia was determined. After harvesting, spores were submitted to quality control to assess concentration, germination, purity, moisture content and pathogenicity against rose aphid, Macrosiphum rosae L., mealy plum aphid, Hyalopterus pruni and melon aphid, Aphis gossypii Glover. Formulated in different oils, conidia were stored at different temperatures for 16 weeks. Oil-formulated conidia were tested against whiteflies under field conditions.
Results: Among the substrates studied, burgul had the highest yield (21 g/100 g substrate). The optimum time for harvesting was 3 weeks. C:N ratio was also the lowest for conidia produced on burgul which caused the highest mortalities and thus appeared the most virulent against all tested insects. Sunflower oil formulated conidia retained viability for at least 16 weeks at room temperature. The preliminary results indicated some but not significant control of whiteflies in the pot experiments.
Conclusion: M. anisopliae could be mass produced in large quantities on burgul substrate. The quality of produced inocula as measured by endogenous C:N ratios would be largely affected by substrate used for mass production. The quality would also influence the efficacy against target insects. Mass produced conidia could also be stored as dry or formulated in sunflower oil at room temperature up to 16 weeks. Use of endogenous C:N ratio as quality control indicator for high quality inocula is highly recommended. Use of vegetable peels as potential substrate for mass production combined with a recyclable oil as formulant could be a low cost and environmentally sustainable technology for future mass production of entomogenous fungi.