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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #290657
Title: Epidemiology of Plum Pox ‘D’ strain in Canada and the U.S.

Author
item Gottwald, Timothy
item WIERENGA, ERIC - Canadian Food Inspection Agency
item LUO, WEIQI - Rothamsted Research
item PARNELL, STEPHEN - North Carolina State University

Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2013
Publication Date: 3/1/2013
Citation: Gottwald, T.R., Wierenga, E., Luo, W., Parnell, S. 2013. Epidemiology of Plum Pox ‘D’ strain in Canada and the U.S.. Canadian Journal of Plant Pathology. 35:442-457.

Interpretive Summary: This paper describes the North American eradication campaigns in Canada and the U.S. for the virus disease of peach and plum known as Plum Pox Virus (PPV). The disease can devastating to both yield and fruit quality and has international implications for fruit commerce. The eradication campaigns in the U.S. were successful; however, due to fiscal constraints and political decisions, the Ministry of Agriculture halted the eradication program in Niagara, Ontario, Canada prior to extinction of the disease. As the disease continues to increase in Ontario, it threatens to spread into New York State only a few miles across the Niagara River. Survey methods are described that were used during the eradication campaigns and also those used post eradication to detect new outbreaks in New York State for early intervention and eradication. The manuscript also describes a number of characteristics of disease spread and a post-eradication retrospective analysis that determines the best eradication approach that would have extinguished the PPV epidemic in Canada more expeditiously. This retrospective analysis will be useful in future epidemics to more efficaciously eradicate and suppress the disease if or when it reoccurs in the U.S.

Technical Abstract: The successful 10-year Pennsylvania USA Plum Pox Virus (PPV) eradication program was based on vigilant survey followed by removal of all Prunus spp within 500m of confirmed PPV+ trees, resulting in declaration of eradication in October 2009. Whereas, in Ontario Canada the low incidence but widely dispersed PPV epidemic extended throughout the stone fruit industry when first discovered in 2000. The Canadian program was predicated on vigilant survey plus PPV infected tree and block removal to reduce PPV incidence initially, followed by increasingly stringent eradication protocols over time. However, eradication was not achieved prior to program termination in 2011. Retrospective analyses of the Canadian epidemic indicated that the estimated PPV distribution from known sources followed a pulse-peak-decay function. The function indicated that viruliferous aphids transmitted infections most commonly at 43m (peak) from prior infections, but PPV distribution also has a long (decaying) tail. A Weibull model, fitted to the proportion of new PPV-infected trees detected, demonstrated that 95% of new infections occurred within 628m, 465m, and 317m, for 1, 2, and 3-yr moving averages, respectively. Results suggest that eradication might be achievable by employing a 317-628m cull radius. The discontinuation of the PPV eradication program in Ontario will result in an increase of PPV in the region, if no spread prevention measures are implemented, and threaten the nearby New York State stonefruit industry. A risk-based survey methodology for commercial and residential stonefruits has been developed to sample Prunus orchards throughout New York that emphasizes proximity to prior PPV discoveries, and proximity to the Canadian border.