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Pseudomonas syringae pv. actinidiae: the Pathogen That Brings Us Together

J. L. Vanneste
Acta horticulturae 2015 v. no.1095 pp. 21-23
Latinos, Pseudomonas syringae pv. actinidiae, bacterial canker, economic impact, fruit growing, industry, kiwifruit, orchards, pathogens, raw fruit, Chile, China, France, Italy, Japan, Korean Peninsula, New Zealand, Portugal, Spain, Switzerland
It is with great pleasure that I welcome every single one of you to the First International Symposium on Bacterial Canker of Kiwifruit. It is somehow incredible and really impressive to see this morning over 150 delegates from around the world, gathered in the same room ready to discuss and share their knowledge of Pseudomonas syringae pv. actinidiae (Psa), the causal agent of bacterial canker of kiwifruit. It is surprising and impressive, because a few years ago nobody would have predicted that we would have a major international conference about what was, up until very recently, a minor pathogen of a minor crop. Kiwifruit production represents only 0.2% of the global fresh fruit production, and up until 2008 the economic impact of Psa was relatively limited and mostly restricted to Asia (China, Japan and Korea). In 2008, most if not all of the scientific literature on Psa could have been read in one single day. So what happened? We will talk a great deal during this symposium about what happened. But in a nutshell: a new biovar of Psa, biovar 3, spread around the world. The first symptoms were seen in 2008 in Latina, which is the major kiwifruit-producing region in Italy, with over 10,000 ha of gold- and green-fleshed kiwifruit orchards (Balestra et al., 2009; Ferrante and Scortichini, 2009; Vanneste et al., 2011). However, it was not before spring 2009 that it became clear that this outbreak of bacterial canker of kiwifruit was on a scale never seen before. In 2010, Psa biovar 3 was found in several kiwifruit-producing countries in Europe (France, Portugal and Turkey), in New Zealand, and in Chile. The following year it was found in Spain and Switzerland. Almost everywhere Psa biovar 3 was found, devastation followed. The worst case might actually be the Bay of Plenty, the heart of the New Zealand kiwifruit industry, which is where we are meeting today (Vanneste et al., 2013).