O presente trabalho verificou a influência da qualidade da luz na esporulação e crescimento radial do fungo entomopatogênico <i>Metarhizium anisopliae</i> (Metsch.) Sorokin. Para isso utilizaram-se seis linhagens: A₄, A₁₉, E₉, K, M e P; três meios de cultura: Meio Completo (MC), Meio de Arroz (MA) e Batata-dextrose ágar (BDA); seis tratamentos com luz: ?BL? (?black light?), azul, verde, amarelo, vermelho e dia, e uma testemunha (escuro). Verificou-se que o crescimento radial foi mais influenciado pelo meio de cultura do que pela luz. A produção total de conídios aumentou, em média 116%, quando as linhagens foram cultivadas sob luz, mas a amplitude da resposta foi função do meio de cultura, da linhagem e da qualidade de da luz. Linhagens com baixa produção de conídios em MC e BDA recuperaram a capacidade de esporulação em MA mesmo sem tratamento luminoso. A viabilidade dos conídios diminuiu significativamente na linhagem E₉, quando cultivado em MC e iluminada com luzes azul, verde, vermelho, amarelo ou dia.

The present work was carried out in order to study the influence of the quality of light in the radial growth and sporulation of the entomopathogenic fungus <i>Metarhizium anisopliae</i> (Metsch.) Sorokin. It was used six fungus strains, three growth media (complete medium - CM, rice medium - RM and potato-dextrose-agar - PDA). The types of light used were: ?black-light? (BL), blue, green, yellow, red and day lights, and also a check treatment (dark). The radial growth was less influenced by the qualities of light that by the growth media. The best medium was the CM; PDA was superior to the RM. The total yield of conidia increased, in average, 116% when the strains were under light, in relation to dark. The magnitude of response, however was function of the growth medium, the strain, and the quality of light. Strains with low conidia production, where grown on CM and PDA, recovered their capacity of sporulation in RM, even in the dark. The strain E₉ had its conidia viability reduced significantly when grown on MC, under blue, green, red, yellow or day light. Every quality of light increase significantly the production of conidia, but for a maximum yield, it is necessary to determinate the best light, in relation to each strain and growth medium.