Japonica rice, Giza 171, was inoculated with either a dry or fresh soil-based inoculum of cyanobacteria containingAnabaena cylindrica, Anabaena oryzae, Nostoc muscorum andTolypothrix tenuis together with fertilization with urea at 0, 36, 72, or 108 kg N/ha. Fresh inoculum enhanced plant growth, yield and N content in comparison with the dry one. The efficiency of nitrogen utilization from the urea at all N concentrations was improved by using the fresh inoculum. Natural infection with leaf and neck blast caused byPyricularia oryzae Cav. increased with increasing N fertilization. Algalization with the fresh inoculum decreased leaf blast while neck blast was slightly higher in the algalized sub-plots but without considerable yield damage.

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The study aimed to evaluate certain commercial Egyptian rice cultivars in both seedling and adult stages to blast disease, identify rice blast hot spots at different rice governorates, and identify effective rice blast resistance genes and common physiological races of Pyricularia grisea under field conditions during 1994 to 2007 seasons. Fourteen Egyptian rice cultivars were tested during the period of study. In addition, ten Japanese differential varieties and two international differential varieties evaluated at three locations i.e. Sakha, Gemmiza and Zarzora were included and tested under natural infection at blast nursery tests.As for field resistance, the cultivars Giza 171

Two Experiments were carried out in 1999 season. The first was at the experimental farm of Rice Research and Training Center (RRTC),Sakha, whereas the second was at the experimental farm of Gemmiza Research Station. The study aimed to investigate the effect of rice blast disease on yield losses at different growth stages of cvs. Giza 171, Reiho and Giza 176. The cultivars were evaluated in split-plot design as a main plots, wheras the treatments (protection by Beam at the rate of 100g/ fed) at both tillering and heading stages, artificial inoculation with spore suspension of Pyricularia grisea (5×10 4 spores/m 2 ( at tillering and or heading stage (milking, soft dough) and natural infection were allocated as Sub-plots. The highest severity and area under disease progress curve (AUDPC) for leaf blast infection were obtained from artificial inoculation at tillering stage. Also, the highest severity and AUDPC of panicle blast infection were recorded from artificial inoculation at milking stage. Giza 171 was the highest susceptible cultivar during vegetative stage, while Giza 176 was the most susceptible cultivar during heading stage. Maximum actual loss due to blast infection in grain yield and 1000-grain weight was obtained from artificial inoculation at milking stage. Panicle blast infection had stronger influence than leaf blast infection. Whereas yield losses due to panicle infection of Giza 171 were two folds compared to those due to leaf infection. These losses were three and four folds in case of Reiho and Giza 176.