Development of New Management Options for Farmers Based on Pathogen Ecology and Epidemiology
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Mite-vectored virus diseases. Texas A&M AgriLife in Amarillo is a Center of Excellence for wheat research. Over the last 20 years, the plant pathology program has led the wheat improvement team in investigation of a disease complex caused by the mite-vectored viruses Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV) and Wheat mosaic virus (WMoV). These viruses are widespread across the western Great Plains and capable of causing catastrophic yield and quality losses in both wheat forage and grain production. It has become clear that a two-pronged approach will be required to ensure sustainable wheat production now and into the future. First, integration of results from previous and ongoing research will be required to develop a comprehensive disease management program, which will include a risk assessment model for mite-vectored virus diseases (MVVD), an action threshold for site-specific vector control and application of cultural practices that rely on a thorough understanding of vector ecology and disease epidemiology. Secondly, to ensure long term sustainability, disease resistant germplasm will have to be identified, incorporated into commercially superior cultivars and deployed in a manner that promotes durable resistance and avoids unintended consequences, such as altering pathogen populations. Similar to release of a new wheat cultivar through the combined efforts of the wheat improvement team, the comprehensive disease management program that will result from this project will mark the culmination of years of work and research by the Amarillo plant pathology program and also identify the needs and direction for future work.Zebra Chip. Eco-epidemiology of vector-borne diseases is complex, requiring deeper understanding of both the pathogen and vector biology, and their interactions, before attempting to implement any form of prevention or control tactics. 'Candidatus Liberibacter solanacearum' (Lso), vectored by the potato psyllid Bactericera cockerelli is no different. In fact, the pathosystem is far more complex than just an ordinary pathogen-vector-disease association because of the fact that it involves different vector and pathogen haplotypes, and various host genera. Knowledge of interactions among these different entities [host (different genera) ´ vector (different haplotypes) ´ pathogen (different haplotypes)] in terms of host reactions, vector transmission abilities, haplotype competitiveness, and disease development is critical in development of sustainable management practices. Currently there are two genetically distinct haplotypes of Lso (A&B) identified from potatoes, and both can be detected individually or together in plant and psyllid samples. In addition, there are four known haplotypes of the psyllid vector identified from potatoes; the central, southwestern, and western haplotypes that have a relatively wide geographic distribution and the northwestern haplotype, which has only been identified in the Pacific Northwest.........