CLEISTOTHECIA PREVALENCE OF POWDERY MILDEW CAUSED BY Eryslphe betae ON SUGAR BEET FIELDS IN EGYPT. | ||||
| Journal of Plant Production | ||||
| Article 5, Volume 29, Issue 9, September 2004, Page 4941-4951 PDF (632.33 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2004.238797 | ||||
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| Author | ||||
| M. E. Abdalla, | ||||
| Plant Pathology Dept., Faculty of Agriculture, Mansoura University, EI· Mansoura 35516, Egypt. | ||||
| Abstract | ||||
| The first appearance of powdery mildew symptoms on sugar beet plants usually occurred on late winter and early summer in Dakahlia govemorate, Egypt. On the basis of the observation, field study that conducted between 1st week of April and May in 2002 and 2003 to assess the Incidence and severity of the mildew on some commercial cultivars. Results showed a constant increase of mildew incidence an~ severity that occurred regularly as the time pass. There were a significant differences in mildew Incidence and severity between plots in edges and inside the fierd. In late April, Cleistolhecia were formed in abundance on all inspected cultivars in 2002 and 2003. Differences in cleistothecia density were observed on old and young leaves or in abaxial and adaXial surfaces of the leaves. Percentage of mature leistothecia ranged from 35 to 55% in early inspection and reached 85% in late inspections. Percentages of viable cleistolhecia were 70.8; 26.8 and 48.8% for the ategories of fresh; soil stored and indoor stored cleistothecia; respectively. Viable cleistotheCia from the three categories used in the pathogenicity test showed different results In percentage of reproduced powdery mildew symptoms on plants exposed to ascospores inoculum. These results clearly show that cleistothecia of Erysiphe betae (Vanha) Weltzlen can be considered as important source of inocula for powdery mildew of sugar beet in Egypt. Prevalence and perennation of cleistothecia could sustain the possibility of the development of new. and perhaps more virulent races of mildew. Keywords: sugar beet, powdery mildew; cleistothecla, Erysiphe betae. | ||||
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