Stability of Beauveria bassiana (Bals.) Vuill. conidia stored in different packagings

ABSTRACT: One of the limiting factors in the use of more substantial amounts of entomopathogenic fungi is the difficulty in maintaining conidial viability for long periods in storage. The need for developing formulations and packaging that would increase the shelf life of these microorganisms is therefore important. Considering this, this study aimed to identify packaging types that would maintain conidial viability for long storage periods at different temperatures. A granular B. bassiana (CG 432) mixture (conidia and parboiled rice) was used, stored in three different packaging types: Coex, metallized polyester, and polyethylene, which were stored in refrigerator (6 ± 2°C) and in an incubator (25 ± 1°C) for 180 days. Germination percentage and water content were the parameters used to evaluate packaging influence on conidial viability. The conidia stored in Coex packaging showed the highest germination percentage in refrigerator and at room temperature during the entire storage period. This packaging also provided the lowest water acquisition by the conidia during storage. Regardless of packaging, the conidia stored in refrigerator showed the highest germination percentage in relation to those stored at room temperature (25 ± 1°C).摘要：昆虫病原真菌（entomopathogenic fungi）大规模应用的限制因素之一，是难以在长期贮存过程中维持分生孢子活力（conidial viability）。因此，开发可延长这类微生物贮存寿命（shelf life）的制剂与包装方案具有重要意义。鉴于此，本研究旨在筛选可在不同温度下长期贮存并维持分生孢子活力的包装类型。本实验采用由分生孢子与蒸谷米复配的颗粒状球孢白僵菌（B. bassiana）CG 432混合物，分别装入Coex包装、镀铝聚酯膜（metallized polyester）与聚乙烯（polyethylene）三种包装材料中，并分别在冷藏箱（6±2℃）与培养箱（25±1℃）中贮存180天。本研究以萌发率（germination percentage）与含水量（water content）作为评价包装对分生孢子活力影响的参数。结果显示，在整个贮存周期内，采用Coex包装的分生孢子在冷藏与室温条件下均表现出最高的萌发率；同时，该包装可使分生孢子在贮存过程中的吸水量降至最低。无论采用何种包装，冷藏贮存的分生孢子萌发率均高于室温（25±1℃）条件下贮存的分生孢子。