McKay A H, Förster H, Adaskaveg J E
Department of Plant Pathology and Microbiology, University of California, Riverside 92521.
Plant Dis. 2012 Feb;96(2):235-242. doi: 10.1094/PDIS-06-11-0525.
Few postharvest treatments are available for managing sour rot of citrus caused by Galactomyces citri-aurantii and they are generally not very effective. The demethylation-inhibiting (DMI) triazole fungicides propiconazole and cyproconazole were found to be highly effective and more efficacious than other DMIs evaluated, such as metconazole and tebuconazole, in reducing postharvest sour rot of citrus. Additional studies were conducted with propiconazole as a postharvest treatment because it has favorable toxicological characteristics for food crop registration in the United States and the registrant supports a worldwide registration. Regression and covariance analyses were performed to determine optimal time of application after inoculation and fungicide rate. In laboratory studies, decay incidence increased when propiconazole applications were delayed from 8 to 24 h (lemon) or 18 to 42 h (grapefruit) after inoculation. Effective rates of the fungicide were 64 to 512 μg/ml and were dependent on inoculum concentration of the sour rot pathogen and on the type of citrus fruit. Propiconazole was found to be compatible with sodium hypochlorite at 100 μg/ml and 1 to 3% sodium bicarbonate without loss of efficacy for decay control on lemon. The addition of hydrogen peroxide/peroxyacetic acid at 80 μg/ml slightly decreased the effectiveness of propiconazole. Heated (48°C) solutions of propiconazole did not significantly improve the efficacy compared with solutions at 22°C. In experimental packing-line studies, aqueous in-line drenches applied alone or followed by applications of the fungicide in storage or packing fruit coatings were highly effective, reducing sour rot to between 0 and 1.2% compared with 83.8% decay incidence in the control when treatments were made up to 16 h after inoculation. When the fungicide was applied in either fruit coating, decay was only reduced to 49.1 to 57.1% incidence. Tank mixtures of propiconazole with the citrus postharvest fungicides fludioxonil and azoxystrobin were highly effective in reducing green mold caused by isolates of Penicillium digitatum sensitive or moderately resistant to imazalil and sour rot. Propiconazole will be an important postharvest fungicide for managing sour rot of citrus and potentially can be integrated into current management practices to reduce postharvest crop losses caused by DMI-sensitive isolates of P. digitatum.
目前几乎没有针对由柑橘乳孢霉引起的柑橘酸腐病的采后处理方法，而且这些方法通常效果不太理想。研究发现，脱甲基抑制（DMI）三唑类杀菌剂丙环唑和环丙唑在减少柑橘采后酸腐病方面非常有效，且比其他评估过的DMI杀菌剂（如戊唑醇和戊唑醇）更有效。由于丙环唑在美国食品作物注册方面具有良好的毒理学特性，且注册人支持全球注册，因此对其进行了更多采后处理研究。进行了回归分析和协方差分析，以确定接种后最佳施药时间和杀菌剂用量。在实验室研究中，接种后若将丙环唑的施药时间从8小时推迟至24小时（柠檬）或从18小时推迟至42小时（柚子），腐烂发生率会增加。该杀菌剂的有效浓度为64至512微克/毫升，这取决于酸腐病原菌的接种浓度和柑橘果实的类型。研究发现，丙环唑与100微克/毫升的次氯酸钠以及1%至3%的碳酸氢钠兼容，对柠檬腐烂控制的效果不会降低。添加80微克/毫升的过氧化氢/过氧乙酸会略微降低丙环唑的有效性。与22°C的溶液相比，48°C的丙环唑加热溶液的效果没有显著提高。在实验包装线研究中，单独进行在线水浸处理，或在储存或包装水果涂层时随后施用该杀菌剂，效果都非常好，与接种后16小时内进行处理的对照组83.8%的腐烂发生率相比，酸腐率降至0至1.2%。当在任何一种水果涂层中施用该杀菌剂时，腐烂发生率仅降至49.1%至57.1%。丙环唑与柑橘采后杀菌剂咯菌腈和嘧菌酯的桶混制剂在减少由对抑霉唑敏感或中度耐药的指状青霉分离株引起的绿霉病和酸腐病方面非常有效。丙环唑将成为管理柑橘酸腐病的一种重要采后杀菌剂，并有可能融入当前的管理措施中，以减少由对DMI敏感的指状青霉分离株造成的采后作物损失。
