臺灣酪梨園根腐病原菌 Phytophthora cinnamomi 對於亞磷酸之生體外感受性測試
Other Title
The Variation of in vitro Sensitivity of Phytophthora cinnamomi Isolates to Phosphite from Avocado Orchards in Taiwan
Journal
台灣農業研究
Journal Volume
75
Journal Issue
3
Start Page
565
End Page
571
ISSN
2790-086X
Date Issued
2026-09-15
Author(s)
嘉義農業試驗分所
嘉義農業試驗分所
Abstract
由 Phytophthora cinnamomi 造成之酪梨根腐病 (Phytophthora root rot) 是世界上危害酪梨最重要之病害之一。目前在許多國家，使用亞磷酸進行防治已行之有年，然而，長期使用亞磷酸可能導致對亞磷酸具耐受性之菌株產生。因此，本研究旨在調查臺灣不同地區 P. cinnamomi 菌株對亞磷酸的敏感性。本試驗挑選臺中、南投、雲林、嘉義及臺南共 18 處酪梨園中共 51 株 P. cinnamomi 菌株進行測試，利用添加不同濃度亞磷酸之5% V8 培養基對病原菌進行菌絲生長抑制率測試並計算抑制 50% 生長的有效濃度 (the effective concentration to reduce growth by 50%; EC50)。本次試驗結果顯示，多數菌株對亞磷酸具敏感性，共有 22 株菌株 EC50 值介於 10–15 mg L-1 之間；而有 7 株菌株對於亞磷酸具有耐受性，EC50 值介於 41–67 mg L-1 之間；此外，試驗發現於嘉義市分離之 3 株 P. cinnamomi 菌株 EC50 值超過 100 mg L-1，顯示該區域有強力抗亞磷酸之菌株且有擴散的風險。而以菌株配對型分析 EC50 值範圍，發現 A2 配對型菌株之 EC50 值差異性較高。地區分析上，臺中與嘉義地區同時存在 2 種配對型之菌株，且均存在耐受性菌株 (EC50 > 35 mg L-1)，顯示存在病原菌透過有性生殖傳播抗藥性之風險。本研究之結果將有助於國內建立有效且永續使用亞磷酸防治酪梨根腐病之策略。
Phytophthora root rot (PRR) caused by Phytophthora cinnamomi is the most important disease of avocado worldwide. Phosphonate fungicides have been applied to manage this disease for decades in many countries. However, phosphite use has increased tolerance to phosphite in P. cinnamomi isolates. This study aimed to investigate the phosphite sensitivity of P. cinnamomi isolates collected from different avocado orchards in Taiwan. A total of 51 P. cinnamomi isolates were obtained from 18 avocado orchards located in Taichung, Nantou, Yunlin, Chiayi, and Tainan. The in vitro sensitivity of mycelial growth to phosphite was measured on 5% V8 agar at different phosphite concentrations, and the effective concentration to reduce growth by 50% (EC50) values were determined. Most isolates were sensitive to phosphite, with 22 isolates exhibiting EC50 values ranging from 10 to 15 mg L-1. Seven isolates showed tolerance to phosphite, with EC50 values ranging from 41 to 67 mg L-1. Moreover, three isolates obtained from Chiayi City had EC50 values exceeding 100 mg L-1, indicating the presence of highly resistant isolates in that region. Analysis of mating types revealed that A2 isolates displayed a wider range of EC50 values. The regional analysis revealed that both mating types and tolerant isolates (EC50 > 35 mg L-1) were present in orchards in Taichung and Chiayi, indicating a potential risk of the dissemination of resistant isolates via sexual reproduction. The results of this study will provide essential information for developing effective and sustainable phosphite management strategies against avocado root rot in Taiwan.
Subjects
酪梨
根腐病
Phytophthora cinnamomi
Avocado
Root rot
Phytophthora cinnamomic
Publisher
農業部農業試驗所
Type
short communication
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