| 論文英文摘要 |
Since fall armyworm (Spodoptera frugiperda) invade into Taiwan in 2019, this pest has severely damaged food crops such as corn and sorghum. The larvae chew on corn leaves, tassels, and bore into the growth points to feed, resulting in reduced yield and quality. Currently, chemical pesticides are the primary control method, but long-term use can lead to development of resistance. Therefore, this study aims to use entomopathogenic fungi (EPF) as control agents, selecting strains with potential to control the fall armyworm and tolerate to different abiotic stresses. The tested strains included Cordyceps javanica PMEPF02, Beauveria bassiana PMEPF11, PMEPF23. The pathogenicity of the five strains against fall armyworm larvae was tested using the leaf-dip method. The results showed that PMEPF02 strain had the highest pathogenicity, with an LT50 of only 1.69 days. Followed by PMEPF11, and PMEPF23, with LT50 values of 3.27, and 6.11 days, respectively. In ultraviolet tests, PMEPF11 exhibited the best tolerance; after 15 minutes of UV-B treatment, it still had a germination rate of 42%. Agricultural chemicals, including the recommended fungicide propiconazole and herbicides glufosinate-ammonium and pyrazosulfuron-ethyl for corn, inhibited conidia germination of the four test strains. Additionally, combining B. bassiana PMEPF11 with the commercial Bacillus thuringiensis subsp.aizawai strain NB-200 product not only enhanced the insecticidal effect but also reduced the LT50 to 0.68 days. In summary, B. bassiana PMEPF11 is a potential strain for controlling the fall armyworm, and combining it with the commercial B. thuringiensis product can shorten the lethal time. |