Chaijuckam Patcharavipa, Davis R Michael
Department of Plant Pathology, University of California, Davis 95616.
Plant Dis. 2010 Aug;94(8):986-992. doi: 10.1094/PDIS-94-8-0986.
Aqueous extracts from ginger, pepper, basil, and garlic plants and essential oils from neem, garlic, lemongrass, and cinnamon were evaluated for their antagonistic effects against Rhizoctonia oryzae-sativae, the cause of aggregate sheath spot of rice. The compounds in 5% concentrations in water or agar were tested on several R. oryzae-sativae isolates. Cinnamon oil, the most efficacious plant product in vitro, was further tested in the greenhouse for the control of the disease on two rice cultivars inoculated with R. oryzae-sativae. One milliliter of each of four cinnamon oil concentrations (12.5, 37.5, 62.5, or 87.5%) diluted in vegetable oil was applied to the surface of the water in constantly flooded pots. Cinnamon oil failed to reduce the disease caused by one of the isolates at any concentration. Cinnamon oil suppressed the disease caused by the other isolate on one of the cultivars at a concentration of 37.5%, and on both cultivars at a concentration of 62.5 and 87.5%. However, cinnamon oil at 87.5% was phytotoxic. Cinnamon oil has potential to control aggregate sheath spot but relatively high concentrations were required for disease suppression.
对姜、胡椒、罗勒和大蒜植株的水提取物以及印楝、大蒜、柠檬草和肉桂的精油进行了评估,以研究它们对引起水稻菌核病的稻梨孢菌的拮抗作用。在水中或琼脂中5%浓度的化合物对几种稻梨孢菌分离株进行了测试。肉桂油是体外最有效的植物产品,在温室中进一步测试了其对两种接种了稻梨孢菌的水稻品种病害的防治效果。将四种肉桂油浓度(12.5%、37.5%、62.5%或87.5%)各1毫升稀释在植物油中,施用于持续淹水花盆的水面上。肉桂油在任何浓度下都未能降低由其中一种分离株引起的病害。肉桂油在37.5%的浓度下抑制了其中一个品种上由另一种分离株引起的病害,在62.5%和87.5%的浓度下对两个品种的病害均有抑制作用。然而,87.5%的肉桂油具有植物毒性。肉桂油有控制菌核病的潜力,但需要相对较高的浓度来抑制病害。