Bowers John H, Locke James C
United States Department of Agriculture-Agricultural Research Service (USDA-ARS), U. S. National Arboretum, Floral & Nursery Plants Research Unit, Beltsville, MD 20705.
Plant Dis. 2004 Jan;88(1):11-16. doi: 10.1094/PDIS.2004.88.1.11.
Formulated plant extracts and oils were investigated for control of diseases caused by Phytophthora spp. Soil infested with chlamydospores of Phytophthora nicotianae was treated by incorporating 1, 5, and 10% aqueous emulsions of formulations containing clove oil, neem oil, pepper extract and mustard oil, cassia extract, synthetic cinnamon oil, or the fungicide metalaxyl. Population densities of P. nicotianae were determined at 0 (before treatment), 1, 3, 7, 14, and 21 days after treatment. Treatment of the soil with 5 and 10% aqueous emulsions resulted in significant (P < 0.05) differences among treatment mean values at each assay date. After 1 day, population densities were reduced to below the limit of detection (<0.04 CFU/cm) in soil treated with 10% aqueous emulsions of two pepper extract-mustard oil formulations and two cassia extract formulations, and near the limit of detection for a synthetic cinnamon oil formulation. Over time, populations of P. nicotianae were detected in the assay; however, after 21 days, populations of P. nicotianae in soil treated with one of the pepper extract-mustard oil formulations still were not detected. Formulations of clove oil, another pepper extract-mustard oil combination, the two cassia extracts, and the synthetic cinnamon oil reduced populations 98.4 to 99.9% after 21 days compared with the nontreated control soil. The neem oil formulation and metalaxyl did not reduce pathogen populations at any rate tested. In the greenhouse after 35 days, 10% aqueous emulsions of a pepper extract-mustard oil formulation, a cassia extract, and the synthetic cinnamon oil formulation suppressed disease development in periwinkle 93.0 to 96.7% compared with the nontreated infested soil. The observed reduction in the pathogen population and significantly more healthy plants in the greenhouse indicates that these formulations of plant extracts and oils could have important roles in biologically based management strategies for control of diseases caused by P. nicotianae.
研究了配方植物提取物和油类对疫霉属病菌引起的病害的防治效果。用含有丁香油、印楝油、辣椒提取物、芥子油、桂皮提取物、合成肉桂油或杀菌剂甲霜灵的制剂的1%、5%和10%水乳液处理被烟草疫霉厚垣孢子侵染的土壤。在处理前（0天）、处理后1天、3天、7天、14天和21天测定烟草疫霉的种群密度。用5%和10%水乳液处理土壤后，各测定日期的处理平均值之间存在显著差异（P < 0.05）。处理1天后，用两种辣椒提取物-芥子油制剂和两种桂皮提取物的10%水乳液处理的土壤中，种群密度降至检测限以下（<0.04 CFU/cm），一种合成肉桂油制剂的土壤中种群密度接近检测限。随着时间的推移，在测定中检测到了烟草疫霉种群；然而，21天后，用一种辣椒提取物-芥子油制剂处理的土壤中仍未检测到烟草疫霉种群。与未处理的对照土壤相比，丁香油制剂、另一种辣椒提取物-芥子油组合、两种桂皮提取物和合成肉桂油制剂在21天后使种群数量减少了98.4%至99.9%。印楝油制剂和甲霜灵在任何测试浓度下均未降低病原菌种群数量。在温室中35天后，与未处理的侵染土壤相比，一种辣椒提取物-芥子油制剂、一种桂皮提取物和合成肉桂油制剂的10%水乳液抑制长春花病害发展的程度为93.0%至96.7%。在温室中观察到的病原菌种群数量减少以及健康植株显著增多表明，这些植物提取物和油类制剂在基于生物学的烟草疫霉病害防治策略中可能发挥重要作用。
