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[9000698.] رقم البحث : 9000698 - |
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Agricultural practices in relation to the major disease problems management of canola in Egypt / |
| تخصص البحث : General |
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Agricultural Research Journal Suez Canal University / |
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M.A. El-Korashy |
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cultural practices - white rust - Alternaria spots |
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Isolation trails from infected seedlings and canola plants showed symptoms of root rot, charcoal rot and wilt diseases yielded three soil born fungi. However, they were identified as Rhizoctonia solani (K?hn), Macrophomina phaseolina (Tassi) Goid. and Fusarium oxysporum (Schlecht). R. solani was the most frequently isolated fungus (45.4%) followed by F. oxysporum (29.7%) and M. phaseolina (24.9%).
The impact of various cultural practices on economically important foliar diseases of canola (Brassica napus L.) in Ismailia Governorate was discussed during 2000-2001 and 2001-2002 seasons. The diseases considered were white rust (Albugo candida), Alternaria leaf, stem and fruit spots (Alternaria spp.), downy mildew (Peronospora parasitica), charcoal rot (Macrophomina phaseolina), wilt (Fusarium oxysporum) and root rot (Rhizoctonia solani).
Studying the effect of inoculum density of the fungal propagules in the infested soil and crop amendments to soil, on soilborne diseases showed positive reaction against incidence of root rot, wilt and charcoal rot. Infection percentage increased by increasing the fungal propagules density of R. solani (the cause of root rot), F. oxysporum (the cause of wilt) and M. phaseolina (the cause of charcoal rot). Regarding the effects of soil amendments on charcoal rot, root rots and wilts diseases, adding soybean, sesame, maize, sunflower and peanut straw to soil one weak before planting greatly reduced infection by these diseases. The least disease incidences were observed with maize, soybean or sunflower straw.
Planting on ridges decreased the severity of these diseases incidence and increased the seed yield. The 60-cm apart was better than 30-cm apart in this respect. Also, the 20-cm hill spacing decreased the diseases incidence as compared to 10 and 15-cm hill spacing. On the other hand, planting canola on Oct. 15 gave generally the least infection by diseases and increased the seed yield as compared with planting on Sept. 15 or Nov. 15 in two tested seasons. In contrast, the highest severity of the diseases incidence was recorded in sprinkler irrigation than surface one, since 15 min. irrigation every 48 hrs gave the less severity of the diseases incidence than 30 and 45min.
Downy mildew, Alternaria spots, white rust and damping off were increased with increasing the level of nitrogen (N) fertilizers, while it decreased by increasing the level of phosphorus (P) and potassium (K) fertilizers. The seed yield was always increased by increasing K level. Generally, the best level of NPK fertilizer in minimizing these diseases and maximizing seed yield was (25-60-48) unit NPK. On the other hand, percentage of pre-emergence damping-off was decreased in depth 2-cm than 3 or 4-cm. |
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