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1 发病原因一是散落在田间土壤中的病菌冬孢子,可存活2～3a,且必须经过一个秋、冬、春季的生理后熟过程,才能萌发。病菌冬孢子通过牛的消化道,仍能保持活力。所以,土壤、粪肥是玉米丝黑穗病的主要侵染源。二是玉米种植面积过大,难以换茬,多年连作,加之气候干旱,导致土壤中病菌逐年积累,致使玉米丝黑穗病的侵染源增多,这是该病发生的首要原因。三是同一品种的多年种植,导致该品种的种性退化,抗逆性降低,是该病发生严重的又一原因。
1 pathogenesis First, scattered in the soil in the field of soil bacteria teliospores, can survive 2 ~ 3a, and must go through a autumn, winter and spring physiological after-ripening process in order to germination. Pathogens through the digestive tract of cattle spores, still maintain its vitality. Therefore, soil and manure are the main sources of maize head smut. Second, corn acreage is too large, it is difficult to stubble, continuous cropping years, combined with the arid climate, resulting in accumulation of soil bacteria year after year, resulting in maize head smut more sources of infection, which is the primary cause of the disease. Third, the same variety of multi-year planting, resulting in species degeneration, reduced resistance is another serious cause of the disease.