Native Trichoderma harzianum Tolerates Abiotic Stress and Reduces Feeding Performance of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)
Ivan Renn Bataclan1,2, Prakaijan Nimkingrat3, and Nanette Hope Sumaya1,2*
1Department of Biological Sciences, Mindanao State University-Iligan Institute of Technology
2Flora Biodiversity Laboratory – Premier Research Institute of Science and Mathematics
3National Biological Control Research Center – Khon Kaen University
Heat and UV-B are damaging environmental factors that affect the viability of endophytic fungi in the field, impacting crop protection and development. In this study, we tested the response of a native Trichoderma harzianum BDP05311, isolated from agricultural soils in Western Mindanao, Philippines, to heat stress at 45℃ and UV-B irradiation at 1000 mW m−2 for durations of 0, 2, 4, and 8 hours, followed by a 24-hour incubation. Simultaneously, feeding performance of fifth to sixth instar Spodoptera frugiperda larvae was assessed on maize leaves treated with a concentration of 1×108 conidia mL-1. Conidia of T. harzianum BDP05311, exposed to heat, exhibited high relative spore germination rates (60%-80%) after 2 and 4 hours of exposure, while germination was significantly reduced after 8 hours (12.5%). Similarly, UV-B exposure showed comparable germination patterns; after 4 hours of exposure, medium germination was observed (51%), followed by low germination after 8 hours (10.3%). Furthermore, maize leaves treated with T. harzianum BDP05311 resulted in a 72.07% reduction in feeding performance for fifth to sixth instar S. frugiperda larvae. Taken together, native T. harzianum BDP05311 offers new insights into the variability of native fungal isolates in tolerating abiotic stress and reducing the feeding performance of S. frugiperda larvae. These findings could be harnessed for the development of sustainable crop protection strategies.