Molasses-Based Medium Requires no Nitrogen Supplement for Culturing Three Entomopathogenie Fungi

The suitability and economics of molasses-based media supplemented with different nitrogen sources for mass production of the entomopathogenic fungi Beauveria brongniartii (Saccardo) Petch, Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschinikoff) were evaluated. Radial growth of all three fungi on molasses agar media differed significantly among different nitrogen supplements. The salts NaNO, and KNO-supported the highest radial growth. Yeast extract, soyflour and defatted soyameal were next best while fertilizer grade urea inhibited growth of B. brongniartii. Spore production of B. brongniartii or M. anisopliae did not differ significantly among molasses broth media fortified with different nitrogen supplements. In B. bassiana, however, yeast extract supported significantly highest spore production and fertilizer grade urea the lowest. A comparison of cost of components for the production of the fungi showed that molasses medium without any nitrogen source was least expensive compared to all other media fortified with different nitrogen sources.