Document Type : Original Article
Department of Botany, Andhra University, Visakhapatnam. India.
Weeds are responsible for heavy yield losses in rice, to the extent of complete crop failure under severe infestation conditions. They occur in every field of rice (Oryza sativa) in the world which is the vital food for more than two billion people in Asia. A systematic field study was conducted in paddy field of Devarapalli Mandal, West Godavari District, Andhra Pradesh, India. Infested weeds were collected in paddy field crops for plants identification, observation, and collection. The random quadrant method was adopted for this study. The collected diseased weed plants were carried out for the extensive study on symptoms, isolation and pathogenicity of the organisms that involved in leaf spot diseases. The causal agents of diseased weed plants were isolated. The inoculated fungal pathogens are incubated on PDA for pure cultures. After harvesting of spores they were observed under the microscope. The study is used to know host specificity of isolated fungal pathogens on test plants and also used to identify bio control agents for crop development. Investigator hopes that diseased weeds of rice fields in study area provide good source of information of technical and taxonomic data to the academic institutes and research organizations like Agricultural colleges, Universities, Agricultural Universities and other agricultural agencies