Epidemiology of citrus canker :a systems analysis approach

• Grant number: 99/12595-0
• Support Opportunities: Research Projects - Thematic Grants
• Duration: June 01, 2001 - May 31, 2006
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Armando Bergamin Filho
• Grantee: Armando Bergamin Filho
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Pesquisadores principais: Takao Namekata

Abstract

This research project includes two independent subprojects that, jointly analyzed, will allow a better understanding of the structure and behavior of the pathosystem Citrus-Xanthomonas-Phyllocnistis. The title of the subprojects are: (i) Citrus canker: spatial and temporal dynamics under natural epidemics and (ii) citrus canker: monocyclic components under controlled conditions. The project will be carried out for four years. The first subproject will characterize, by fortnightly assessments, the citrus canker progress curves and its spatial patterns, the progress curves of the miner Phyllocnistis citrella and its spatial patterns, and the plant phenology, considering the following treatments and its combinations: (i) with and without windbreaks, (ii) with and without control of the bacteria (Xanthomonas axonopodis pv. citri), and (iii) with and without control of the leaf miner (Phyllocnistis citrella). This is the first time that a simultaneous assessment of those variables is proposed for this pathosystem. Additionally, deposition and disease gradients will be characterized for all treatments, by the use of trap-plants and standard spore-traps. The second subproject attempts to elucidate the role of different factors of weather, host and pathogen like temperature, wetness period, citrus cultivar, leaf age, presence and type of wounds on the leaves on the monocyclic components (frequency of infection, incubation period, lesion size, and disease severity) of citrus canker under controlled conditions. This type of information is essential for complementing the conceptual model about the disease that will be drawn from the results of the experiments carried out under natural epidemics in the field (subproject 1). The knowledge of the structure and behavior of the pathosystem Citrus-Xanthomonas-Phyllocnistis is a conditio sine qua non for the definition of a rational strategy of eradication and/or economic management of citrus canker adapted to the different conditions of the State of São Paulo, Brazil. (AU)