Tomato Potato Psyllid/Zebra Chip

Plant & Food Research, Potatoes NZ and Foundation for Arable Research

The problem: A new invasive insect/plant pathogen complex is creating production and quality issues in potato crops in New Zealand that are currently being addressed using insecticide applications. Research is being directed to identify technologies for managing potato crops sustainably to support an integrated pest management approach.

Key stakeholders: Potatoes NZ, Foundation for Arable Research, MBIE, Plant & Food Research researchers, business managers and senior managers, individual potato growers, chemical companies, consultants, merchants, providers of TPP monitoring services, other research providers and collaborators, Market Access Solutionz, MPI SFF and processors.

Timeline: Tomato potato psyllid (TPP) was first detected in New Zealand in 2006. It is now found in potato-growing regions in both islands. The psyllid is associated with the plant-pathogenic bacterium Candidatus Liberibacter solanacearum (CLso), which was identified in 2008. This tritrophic interaction, psyllid-bacteria-plant, is `new to science’, making research challenging and management solutions difficult to identify. The TPP/CLso complex reduces yield and quality of the crop; in particular it reduces dry matter. This results in ‘Zebra Chip’ (darkening) when potatoes are fried, rendering some tubers unacceptable for processing.

The New Zealand potato industry has estimated that the arrival of the psyllid has cost the industry around $60 million since 2008 in increased inputs and decreased yields. Currently, TPP is controlled by carefully timed insecticide applications. In 2013 Lincoln University’s Agribusiness Economics Research Unit reported that “savings in pesticide regimes alone of more than one million dollars per year are already being achieved”.
In 2013 the total value of exports from the sector was $110 million at FOB, of which almost 86% comprised processed product.

This innovation project focuses on an MBIE-funded programme called ‘Realising potato export growth through sustainable management of the zebra chip disease complex’. This programme is identifying chemical, visual and auditory cues that the psyllid uses to locate host plants or mates. It also seeks to understand genetic variability in psyllid populations in relation to host plant preference, CLso uptake and transmission, and insecticide resistance. Knowledge of the biology of pest, pathogen and host plant interactions is also essential to guide breeding of resistant or tolerant potato cultivars.

See the Growing Futures for more detail on TPP and its impacts on quality potato production in New Zealand as well as research innovations that are addressing the effects of this disease complex.