Davis R M, Hao J J, Romberg M K, Nunez J J, Smith R F
Department of Plant Pathology, University of California, Davis 95616.
University of California Cooperative Extension, Kern County, Bakersfield 93307.
Plant Dis. 2007 Feb;91(2):204-208. doi: 10.1094/PDIS-91-2-0204.
The ability of soil-applied garlic powder and diallyl disulfide to stimulate germination of sclerotia of Sclerotium cepivorum, the cause of white rot of onion and garlic, was evaluated in four field trials. Because sclerotia germinate in response to exudation of specific volatile sulfides and thiols from allium roots, sulfides applied to the ground in the absence of an allium crop cause death of the sclerotia after they germinate and exhaust nutrient reserves. In this study, garlic powder and a synthetic garlic oil, diallyl disulfide, were incorporated into the soil in commercial fields naturally infested with S. cepivorum. Methyl bromide was included as a chemical control. Within 3 months after treatment, over 90% of the sclerotia died in the plots treated with the germinationstimulants, which was similar to the reduction of viable sclerotia achieved with an application of methyl bromide. The degree of sclerotial mortality in plots treated with garlic powder at 112 kg/ha or more was almost equal to that achieved by diallyl disulfide at 0.5 ml/m or methyl bromide at 448 kg/ha. Despite the efficacy of the stimulants and methyl bromide to reduce populations of sclerotia, the pathogen caused substantial root rot and yield losses in subsequent garlic crops planted about a year after soil treatment. However, germination stimulants have utility because the reduction of the vast majority of sclerotia in a field reduces the risk of spread of the pathogen to neighboring fields.
在四项田间试验中，评估了土壤施用蒜粉和二烯丙基二硫化物对洋葱和大蒜白腐病病原菌——洋葱核盘菌菌核萌发的刺激能力。由于菌核会响应葱属植物根系分泌的特定挥发性硫化物和硫醇而萌发，因此在没有葱属作物的情况下施用于地面的硫化物会导致菌核萌发并耗尽养分储备后死亡。在本研究中，将蒜粉和一种合成大蒜油——二烯丙基二硫化物，施用到自然感染洋葱核盘菌的商业田土壤中。甲基溴作为化学对照物。处理后3个月内，用萌发刺激剂处理的地块中超过90%的菌核死亡，这与施用甲基溴后存活菌核的减少情况相似。以112千克/公顷或更高剂量施用蒜粉的地块中菌核死亡率几乎与以0.5毫升/平方米施用二烯丙基二硫化物或以448千克/公顷施用甲基溴的情况相当。尽管刺激剂和甲基溴在减少菌核数量方面有效，但在土壤处理约一年后种植的后续大蒜作物中，该病原菌仍导致了严重的根腐病和产量损失。然而，萌发刺激剂仍有作用，因为田间绝大多数菌核数量的减少降低了病原菌传播到邻近田地的风险。
