Bactericera cockerelli (Hemiptera: Triozidae) and Candidatus liberibacter solanacearum in potatoes in New Zealand: Biology, transmission, and implications for management

Abstract

Bactericera (Paratrioza) cockerelli (Šulc) (Hemiptera: Triozidae) is a native American psyllid species that was first reported in New Zealand in 2006. In 2008, the insect was associated with a new-to-science pathogen, Candidatus Liberibacter solanacearum (syn. 'Ca. L. psyllaurous') (Rhizobiales: Rhizobiaceae). This pathogen is the putative causal agent of zebra chip disease of potato tubers, which makes them unsuitable for processing, causes disease in seed tubers, and is perceived to affect the taste of fresh market potatoes, as well as their internal appearance. The insect/pathogen complex is also an important economic pest of other solanaceous crops, including tomato, capsicum, tamarillo, and eggplant. Here, we review the literature on the phloem-limited pathogen and focus on the integrated management of its insect vector in New Zealand. Comparisons with other regions of the world are made where appropriate. We review the current understanding and paradigms of insect-mediated transmission of plant pathogens, an increasingly important area as more Liberibacter species are discovered world-wide. Knowledge gaps are identified and recommendations made for future research aimed at defining the fundamental biological parameters underpinning the epidemiology and pathology of the disease caused by Ca. L. solanacearum in potato.