Compatibility of polymers to fungi Beauveria bassiana and Metarhizium anisopliae and their formulated products stability

ABSTRACT. Stability during storage is a limiting factor in the development and use of bioinsecticides. This study aims to evaluate the compatibility of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana with components used in encapsulated formulations and to evaluate shelf-life in formulations with B. bassiana. Sodium alginate and maltodextrin, hemicellulose, and dimethyl sulfoxide solvents were evaluated. Compatibility was evaluated by mixing the components with PDA, and the parameters evaluated were vegetative growth, sporulation and viability. The formulations of fungi were prepared in various concentrations of sodium alginate and then added drop-wise to calcium chloride. To evaluate the stability, formulations were stored at 26.5, 4.0, and -20.0°C. Monthly, samples were taken, and the capsules were placed on Petri dishes with PDA to verify the growth after seven days of incubation. These evaluations were performed by the 12th month. Biopolymers evaluated were compatible with both fungi, exception maltodextrin at 1.5%, which was classified as moderately toxic to B. bassiana. Dimethyl sulfoxide was classified as moderately toxic to B. bassiana at 3.0% and to M. anisopliae at 2.0% and 3.0%. The formulations were stable throughout the 12 months in the conditions evaluated, while for the pure conidia of the fungus, 46% viability in the 6th month at 26.5°C was observed.

摘要 储存稳定性是制约生物杀虫剂开发与应用的关键瓶颈因素。本研究旨在评估两种昆虫病原真菌——金龟子绿僵菌（Metarhizium anisopliae）与球孢白僵菌（Beauveria bassiana）与微囊制剂常用组分的相容性，并探究含球孢白僵菌的微囊制剂的货架期。本次试验评估了海藻酸钠、麦芽糖糊精、半纤维素以及二甲基亚砜溶剂。相容性测试通过将待测组分与马铃薯葡萄糖琼脂（PDA）混合开展，评估指标包括营养生长、产孢量与孢子活力。采用不同浓度梯度的海藻酸钠制备真菌微囊制剂，随后将其逐滴滴入氯化钙溶液中。为评估制剂稳定性，将制备好的微囊分别置于26.5℃、4.0℃与-20.0℃条件下储存。每月采样一次，将微囊置于含PDA的培养皿中，于恒温培养7天后观察真菌生长情况，该评估持续至第12个月。本次评估的生物聚合物与两种真菌均具有良好相容性，但1.5%浓度的麦芽糖糊精对球孢白僵菌表现为中度毒性。3.0%浓度的二甲基亚砜对球孢白僵菌表现为中度毒性，而2.0%与3.0%浓度的二甲基亚砜对金龟子绿僵菌同样表现为中度毒性。在本次评估的储存条件下，制备的微囊制剂在12个月储存期内均保持稳定；而未经包埋的纯真菌分生孢子在26.5℃储存至第6个月时，孢子活力仅剩余46%。