Fluctuations of plant pathogens in sugar factory's waste in Kerman province of Iran

Abstract

Sugar beet roots and the attached soil are transferred to Bardsir factory for processing, and the roots are washed by water pressure. Muddy water flows as waste into canals and are used for irrigation of sugar beet farms. The possibility of occurrence and fluctuations of the pathogenic organisms in irrigation was studied during 2006 and 2007. The samples were collected from the wastewater once a week. Isolation of pathogens was done by four methods: (a) Citrus leaf baiting method and on PARPH selective medium, and common culture media such as: PDA, CMA, MA, NA and WA; (b) Irrigation of sugar beet seedling with wastewater; (c) Bioassay with healthy sugarbeet roots; (d) Cysts of nematode were extracted from waste by sieves. Many different pathogens were isolated from wastewater such as: Fusarium oxysporum, Fusarium solani, Rhizopus stolonifer, Penicillium digitatum, Aspergillus niger, Pythium aphanidermatum, Pythium akanoganese, Phytophthora cryptogea, Phytophthora drechsleri, Mucor sp., Rhizoctonia solani, Geotrichum sp., Erwinia carotovora and cysts of Heterodera schachtii. Pathogencity tests were done for each pathogen. During the first period of processing, the recovery of pythiaceae and Erwinia carotovora was in high level, and in the last period of processing the recovery of Penicillium digitatum, Aspergillus niger, Mucor sp. and Geotrichum sp. showed high levels. The recovery of Alternaria alternata, Rhizoctonia solani and Fusarium solani were stable but the cysts of H. schachtii were variable during the processing period. These pathogens were isolated from sugar beet farms irrigated with wastewater.