- 期刊
Colletotrichum siamense引起之荔枝葉部針點病病原特性及防治藥劑篩選
Physiological Characteristics, Pathogenicity and Fungicide Sensitivity of Colletotrichum siamense Causing Lychee Pepper Spot Disease
摘要
荔枝針點病之病原菌為Colletotrichum siamense，可危害荔枝葉片與葉柄，造成黑色針點狀病斑。本研究由雲林古坑「糯米糍」及「桂味」荔枝品種之針點病病斑上分離得Colletotrichum spp.，經形態觀察及分子類緣關係鑑定確認為C. siamense。由先前研究中確認C. siamense對荔枝「糯米糍」葉部具有病原性，本研究則對荔枝品種「台農7號」進行葉部接種，藉此得知本病原菌亦可侵染糯米糍以外之品種。又進行溫度對C. siamense菌絲生長與孢子發芽影響試驗，結果發現C. siamense菌絲最適生長溫度為25-30℃，且在15℃之低溫時仍可生長；分生孢子則在20-30℃之間皆可於葉片上萌芽並產生附著器。進行C. siamense之菌絲生長與分生孢子發芽對化學藥劑之感受性評估，發現腐絕快得寧及甲基多保淨對菌絲生長具有較佳抑制效果，克熱淨及得克利次之；在抑制分生孢子發芽方面，則以腐絕快得寧、腈硫醌及百克敏有較好的抑制能力，亞托待克利及得克利次之。本研究之結果，可提供作為田間荔枝針點病在防治策略及藥劑施用上之參考。
並列摘要
The causal agent of lychee pepper spot disease is Colletotrichum siamense. The symptom shows black needle-like spots on leaf, fruit, petiole and pedicle. In this study, many isolates of Colletotrichum spp. were isolated from needle-like spots on lychee 'Gue Wei' and 'No Mi Ci' and all of them were identified as C. siamense based on morphology and molecular phylogenetic analysis. In our previous study, the pathogenicity of C. siamense on lychee has been validated on lychee 'No Mi Ci'. In this study, pathogenicity test was conducted on lychee 'TN 7' to confirm that the pathogen causes symptoms on other variety in addition to 'No Mi Ci'. The temperature effect on C. siamense mycelial growth and spore germination was investigated. It was found that the optimal temperature for mycelial growth was 25-30℃, and mycelia growth of C. siamense kept viable under 15℃. In addition, spores germinated and produced appressoria on lychee leaves under 20-30℃. The result of fungicide sensitivity test indicated that thiabendazole + oxine-copper and thiophanate-methyl are the most suppressive on mycelial growth of C. siamense, followed by iminoctadine triacetate and tebuconazole. In addition, thiabendazole + oxine-copper, dithianon and pyraclostrobin had best suppression on spore germination, followed by azoxystrobin + difenoconazole and tebuconazole. The results of this study provide information for fungicide selection and control strategy on lychee pepper spot disease in the field.