Production of Microsclerotia by sp., and Factors Affecting Their Survival, Germination, and Conidial Yield.

Microsclerotia (MS) produced by some species of can be used as active ingredients in mycoinsecticides for the control of soil-dwelling stages of geophilic pests. In this study, the MS production potential of two strains and one strain was evaluated. The three strains were able to produce MS in liquid fermentation, yielding between 4.0 × 10 ( EAMa 01/158-Su strain) and 1.0 × 10 ( EAMa 01/58-Su strain) infective propagules (CFU) per gram of MS. The EAMa 01/58-Su strain was selected for further investigation into the effects of key abiotic factors on their survival and conidial yield. The MS were demonstrated to be stable at different storage temperatures (-80, -18, and 4 °C), with a shelf-life up to one year. The best temperature for MS storage was -80 °C, ensuring good viability of MS for up to one year (4.9 × 10 CFU/g MS). Moreover, soil texture significantly affected CFU production by MS; sandy soils were the best driver of infective propagule production. Finally, the best combination of soil temperature and humidity for MS germination was 22.7 °C and 7.3% (/), with no significant effect of UV-B exposure time on MS viability. These results provide key insights into the handling and storage of MS, and for decision making on MS dosage and timing of application.