Alternative substrates for conidiogenesis of the entomopathogenic fungus Beauveria bassiana (Bals) Vuillemin (Deuteromycotina: Hyphomycetes)

Abstract Beauveria bassiana is a promising fungus for the biological control of insect pests. The growing costs of conidia production have raised the need to ascertain the efficiency of some low cost substrates. The aim of this study was to analyze the potential use of different raw substrates without nutritional supplement for B. bassiana conidiogenesis. Growth and sporulation were evaluated using 30 g of substrate and 0.3 μL of a conidia suspension (1 x 106 conidia/mL). After 10 days of incubation (70 ± 10% humidity and temperature (T) = 29 ± 1 °C), rice (2.00 x 106 conidia/g substrate), algaroba (2.36 x 106 conidia/g), malt A (1.22 x 106 conidia/g) and malt B (1.75 x 106 conidia/g) showed the highest levels of conidia production. The resulting conidia showed insecticidal activity higher than 80% on coconut termites. These new raw substrates may represent viable alternatives for the production of entomopathogenic fungi for use in the biological control of various insect pests.

摘要 球孢白僵菌（Beauveria bassiana）是一种极具应用潜力的害虫生物防治真菌。当前分生孢子（conidia）生产的成本持续攀升，使得研究亟需明确各类低成本基质的使用效率。本研究旨在分析无营养添加的不同天然基质用于球孢白僵菌产孢（conidiogenesis）的潜力。实验采用30g基质与0.3μL浓度为1×10^6孢子/mL的分生孢子悬浮液，对菌株的生长与产孢水平进行评价。在湿度70±10%、温度29±1℃的条件下培养10天后，大米（2.00×10^6孢子/克基质）、阿拉罗巴（algaroba，2.36×10^6孢子/克）、麦芽A（1.22×10^6孢子/克）及麦芽B（1.75×10^6孢子/克）展现出最高的分生孢子产量。所获得的分生孢子对椰子白蚁的杀虫活性均高于80%。上述新型天然基质有望成为生产昆虫病原真菌（entomopathogenic fungi）的可行替代方案，用于各类害虫的生物防治。