蒸熱處理對採後軟熟‘愛文'芒果炭疽病徵發展之影響

Effect of Vapor Heat Treatment on the Symptom Development of Anthracnose in Harvested Ripe 'Irwin' Mango

詹文莉(Wen-Li Chan) ； 吳俊達(Chun-Ta Wu)

《臺灣園藝》 58卷2期 (2012/06) Pp. 103-116

https://doi.org/10.6964/JTSHS.201206.0103

摘要

芒果炭疽病主要由真菌Colletotrichum gloeosporioides Penz.引起，是芒果採後重要的病害，亦為我國‘愛文’芒果外銷過程中劣變的主要原因之一。以試驗用蒸熱機模擬標準蒸熱流程（果心溫度46.5℃維持30 min.）處理軟熟‘愛文’芒果後，置於20℃觀察20天，炭疽病罹病率小於5.3%，顯著低於對照組的發病率66.7%。果實以人工接種炭疽病菌分生孢子後蒸熱與不蒸熱（對照）比較，蒸熱組無接種部位炭疽病斑之發生，但對照組在接種部位病斑發展之直徑達24.2mm。不蒸熱與蒸熱後之果皮接種病菌比較，則顯示蒸熱後之果皮對炭疽病更為感病。將分生孢子在玻璃紙上培養至形成附著器階段，經蒸熱處理後，在馬鈴薯葡萄糖洋菜（potato dextrose agar）培養基培養，菌絲再生長率為6.8%，而未經蒸熱處理者為94.4%，證明蒸熱處理可以殺滅潛伏芒果炭疽病菌，抑制其菌絲再生長。依據模擬蒸熱處理不同致死熱積溫（45℃以上溫度×處理時間）對體外培養之菌絲再生長率迴歸曲線推測，貯運前蒸熱處理熱積溫若達5700℃．min，能降低軟熟‘愛文’芒果炭疽病罹病率到5%以下。

關鍵字

熱處理 ； 致死熱積溫 ； 採後處理

並列摘要

Mango anthracnose, caused by Colletotrichum gloeosporioides Penz. fungus, is a serious postharvest disease of mango; and it is also one of the major causes of fruit deterioration in 'Irwin' mango exported from Taiwan. Ripe 'Irwin' mango treated with standard vapor heat (VH) quarantine procedure (fruit core 46.5℃ for 30 min) in an experimental VH equipment had less than 5.3% anthracnose incidence, significantly lower than the incidence of 66.7% for untreated control in 20 d of storage at 20℃. No anthracnose symptom was found on the conidia-inoculated and then VH treated fruit in 20 d, while the average diameter of the lesions was 24.2 mm on the inoculated fruit without VH treatment. However, when the inoculation was made after VH treatment, the result showed that the susceptibility of the fruit to anthracnose increased by VH treatment. When the quiescent C. gloeosporioides in vitro incubated on cellophane until appressorium-formation stage was either VH treated or not before being cultured in potato dextrose agar medium, the VH treated group had a mycelia regrowth percentage of only 6.8% while the other group, 94.4%. VH treatment apparently had a fungicidal effect on the quiescent conidia and prevented from their hypha regrowth in the culture medium.

並列關鍵字

heat treatment ； lethal heat accumulation ； postharvest handling