棉角斑病对棉花苗、蕾期危害的研究

Studies on Infection of Cotton by Xanthomonas campestris pv. malvacearum (Smith.) During Seedling and Flower bud

近年来,对不同类型棉田角斑病危害调查和以海岛棉为主地病害发生研究,角斑病[Xanthomonas Campestris PV.malvacearum(Smith)Dye]对棉花的危害,以苗、蕾期的顶腐、茎腐最为严重,造成顶梢和茎部黑腐的途径,主要是病菌在棉株组织内的系统侵染。棉子播种试验,毛子播种的棉苗在子叶期就出现病症,脱绒光子的棉苗在真叶3～4片时才出现病害。脱绒光子带有少量的病菌,仍是病害的侵染源,在多雨的气候条件下,可以通过系统侵染和再侵染造成严重危害。

In recent years, we surveyed the incidence and infection of cotton angular leafspot in various cotton fields and studied the infection on Gossypium barbadense L. , Result showed that the system infection of pathogen was the main way which caused cotton top and stem rot. In planting tests of cotton seed, the seedling of fuzzy seed appeared symptom in seedling, and the seedling of delinting seed never appeared symptom untill three or four leaves. The brceence of slight inoculum of delinting seed was merely the first source in infection cycle, and in raining season, the cotton was severely attacked by system and repeated infection.