大蒜在上海市嘉定县每年约种植5万亩,主栽品种为“嘉定白蒜”,以其蒜头大、色白、味辣、肉脆而闻名,是传统的出口农产品,远销东南亚和日本等国。近几年,“嘉定白蒜”的蒜头变小,产量不断降低,品质变差。经调查,发现大蒜上病毒病感染严重,田间植株几乎百分之百感病,只是发病程度轻重不同而已。田间症状:发病重的植株叶子发生扭曲,整个植株矮缩,叶子变宽、变厚,叶色浓绿,长有黄绿色的斑点,且合并产生条斑,出现花叶症状。重病株的蒜苔不易抽出或部分抽出,地下部的鳞茎不发育,不能形成蒜瓣,有时形成畸形的独头蒜,里面充满水分,用手触摸易烂,散发出腐臭气(见图1)。 Garlic in Jiading County, Shanghai, about 50,000 acres planted each year, the main varieties of “Jiading white garlic”, with its garlic large, white, spicy, crisp and famous, is a traditional export agricultural products, exported to Southeast Asia and Japan country. In recent years, “Jiading white garlic” smaller garlic, production continues to decline, poor quality. After investigation, found that garlic virus infection serious, almost 100% of field susceptible strains, only the severity of different severity only. Symptoms in the field: The diseased plant leaves distorted, the entire plant dwarfed, the leaves widened and thickened, the leaf color was dark green, and the plants had yellowish-green spots and merged to produce streaky spots with mosaic symptoms. Severe strains of garlic is not easy to extract or part of the extraction, the underground bulbs are not developed, can not form garlic cloves, and sometimes the formation of deformed single-head garlic, which is full of moisture, easy to touch by hand rotten, emitting rancid odor (see Figure 1).