The severe symptoms of the disease could be observed on vulnerable genotypes when grown under the impact of extreme nitrogen fertilization. ![]() This phase of the disease becomes visible very early in the temperate regions of the rice growing countries with the initial symptoms on the leaf blades after the tillering gain its peak position and usually initiated at lower parts in plants and gradually proceeds towards to the upper areas of the plants ( Goto, 1992 Cha, 1982). The disease could be characterized mainly into two distinct phases leaf blight phase, and the “Kresek phase” which is the destructive one for the epidemic of disease ( Reddy and Ou, 1976 Ou, 1985). The environment played a key role for the development of the disease and the appearance of the symptoms in the field. The lesions normally start on one or both margins of leaves or can be observed on the fresh infected leaf veins under humid conditions. the wavy margins, which can be clearly seen on the leaf blade. Lesions edges were adjoining the healthy areas on the leaves and showing the most characteristic symptom of the disease i.e. Firstly, small water-soaked lesions appear which later turned to yellowish white color expanding from the equal sides in a square form to produce elongated circular to quite uneven lesions. The pores for water percolation are present on leaf edges of the higher area of leave so, lesions normally start at leaf margins on the upper part near the top area. The pathogenic bacterium invades the rice crop plants through the water pores using the fresh wounds of 24 hours ( Mukko, 1957). The present research is based on the screening, estimation of phenolics contents epidemiology and biological control of bacterial blight of rice by plant extracts and detailed reviews of work done previously by the scientists on this issue are being reported in this chapter. The management of the crop plant diseases by utilizing the plant extracts are considered relatively secure as the plants products are economically cost effective, simply biodegradable and prove themselves as environment friendly with their response ( Mariappan, 1995). Up till now researchers gave less importance on the biological management especially using plant extracts. Comprehensive studies were performed on the etiology, epidemiology and biological management of the disease in Multan. The pathogenicity of bacterial leaf blight has confirmed that the causal bacterium is Xanthomonas oryzae pv. Environmental issues are also needed to be addressed in the future research agenda of this disease.īacterial leaf blight of rice is among the most devastating pathosystem of rice in nearly all the rice growing localities in tropical and temperate regions especially in Asian countries. Climate change has a drastic effect for the development of this disease and still there are no remedies to tackle this problem. Since, farming community has adopted rice crop in non-core areas of Indian Sub-continent where it was out of question before this. Climate change has a serious effect on this disease because in current scenarios cropping pattern has been changed and the stakeholders has shifted to some other crops rather the practicing ones. There is a need to use environmentally safe approaches to overcome the loss of grain yield in rice due to this disease. Formulations of various botanicals along with biological agents may be commercializing to help farmers to combat the disease. ![]() Evidence from my laboratory suggest that biological control is the best option having ecofriendly activities for the management either using botanicals or through some biological agents. Up to this extent, multi cropping using resistant varieties appears to be better option for the disease’s management. Studies on pathogen variation have revealed that breeding with single major gene for resistance may be unsuccessful due to breakdown in resistance. This article comprehensively reviews the etiology, symptomatology, pathogen biology, disease development, disease cycle, epidemics and epidemiology, geographical distribution and strategies for the disease management viz., exploitation of host plant resistance, cultural, physical, chemical and biological control. Abstract | This is a status review article on the destructive bacterial blight disease of rice, caused by Xanthomonas oryzae pv.
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