| 論文英文摘要 |
Phytophthora capsici is a significant threat to vegetable production in Taiwan and globally. Streptomyces plicatus isolate B4-7 has emerged as a promising biocontrol agent against Phytophthora blight. Analysis using C18 solid-phase extraction (SPE) fractions of B4-7 in anti-fungal assays against P. capsici demonstrated that lower polarity SPE fractions exhibited robust inhibition of mycelial growth and induced abnormal sporangium formation. To use the biological agent B4-7 together with fungicides in crop disease control, we tested the inhibitory effect of five recommended fungicides on B4-7's mycelium growth through paper disc assays. The results showed that, except for chlorothalonil and copper hydroxide, dimethomorph, etriazole, and metalaxyl, exhibited no inhibitory effects on B4-7. When the B4-7 culture broth was applied to Phytophthora-infested peppers, it resulted in 100% inhibition. Similarly, applying copper hydroxide or etriazole alone to the infested plants yielded the same results. Co-application of half-dosages of B4-7 culture broth and copper hydroxide, or etridiazole, significantly reduced the disease severities (12.5%, 0%) and infection rates (12.5%, 0%) of Phytophthora crown rot disease compared to the control treatments (93.8% and 100%) in peppers. These results suggest the potential of combining S. plicatus B4-7 with fungicides in an integrated approach for Phytophthora blight management. |