福建省芋疫霉交配型测定及防治药剂筛选

王荣波; 石茗月; 徐月华; 刘裴清; 卞润恬; 翁启勇; 李本金

doi:10.19303/j.issn.1008-0384.2024.07.008

福建省芋疫霉交配型测定及防治药剂筛选

Mating Type and Effective Control of Phytophthora colocasiae in Fujian

摘要

摘要:
目的明确福建省芋疫霉交配型，筛选可用于防治芋疫病的化学药剂。
方法对2020年采集自福建4个地区的芋疫病样本进行病原菌分离纯化，结合形态特征观察、致病性测定和Ypt1序列同源性分析对病原菌进行鉴定，通过与辣椒疫霉A1、A2交配型菌株对峙培养来测定其交配型，并利用菌丝生长法测定6种杀菌剂对病原菌的室内毒力。
结果通过形态特征观察、致病性测定和ITS-LSU-Ypt1融合序列同源性分析，明确所分离病原菌均为芋疫霉（Phytophthora colocasiae）。交配型测定发现，所分离的125个芋疫霉菌株中，122个为A2交配型，3个为A1A2交配型。室内药剂筛选结果表明，98%甲霜灵对芋疫霉抑菌效果最好，EC₅₀值为（0.146±0.032） μg·mL⁻¹；95%烯酰吗啉、98%氟吡菌胺和94%氰霜唑抑菌效果较好，EC₅₀值介于（0.239±0.011）~（0.713±0.088） μg·mL⁻¹；而95%嘧菌酯的抑菌活性最低，EC₅₀值为（23.447±3.666） μg·mL⁻¹。
结论福建省芋疫霉以A2交配型为优势群体，甲霜灵、烯酰吗啉、氟吡菌胺和氰霜唑可作为芋疫病高效防控的轮换使用药剂。

Abstract:
Objective Mating type and fungicides for effective control of Phytophthora colocasiae that caused 2020 taro blight epidemic in Fujian were determined.
Method Specimens of diseased taro tissues were collect from the 4 blight-infected regions in Fujian to isolate and identify the pathogen. Based on the morphology, pathogenicity, and sequence homology of ITS-LSU-Ypt1, the pathogenic strains were identified to be of P. colocasiae. Subsequently, mating type and sensitivity to 6 fungicides of the isolates were determined in the laboratory.
Result In total, 125 strains were isolated and identified to have caused the epidemic. Out of them, 122 belonged to the A2 mating type and 3 the A1A2 type. The laboratory toxicity test of 6 fungicides on the isolates showed 98% metalaxyl to be the strongest with EC₅₀ of (0.146±0.032) μg·mL⁻¹, while the EC₅₀ of 95% dimethomorph, 98% fluopicolide, and 94% cyazofamid ranged from (0.239±0.011) μg·mL⁻¹ to (0.713±0.088) μg·mL⁻¹ and that of 95% azoxystrobin at (23.447±3.666) μg·mL⁻¹.
Conclusion The dominant strains of P. colocasiae that caused the taro blight in Fujian in 2020 were of the A2 mating type and could be best controlled by using 98% metalaxyl, 95% dimethomorph, 98% fluopicolide, or 94% cyazofamid.

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