COLLABORATIVE, GROWER-LED RESEARCH TO ADDRESS CHALLENGES Gemma Carroll : Potatoes NZ Inc. communications & engagement officer
Tomato Potato Psyllid (TPP)
The Canterbury Potato Liberibacter Initiative (CPLI) was formed in August 2021 by likeminded Canterbury farmers and industry representatives to combat the devastating impact of the Candidatus Liberibacter solanacearum (Lso) bacterium causing ’zebra chip’ in potato crops. Lso is transmitted by the Tomato Potato Psyllid (TPP). The TPP incursion was first detected in Auckland in 2006 and quickly spread throughout the North Island and then the South Island to as far south as Invercargill, within five to six years. Only three to five percent of TPP in a population will carry Lso; these psyllids are classed as ’hot psyllids.’ Hot psyllids feed on the plant and infect it with Lso, causing zebra chip in the potato tubers. Zebra chip caused production issues
only in the North Island processing plants until 2015, but from 2012 to 2015 Canterbury psyllid populations were increasing and causing quality issues for both growers and processors. Since 2015 insecticide programmes have improved and increased year-on-year with weekly spraying of potato crops to reduce TPP populations. There have been other initiatives with varying levels of success over the years to reduce TPP populations. Although the control measures and agronomy of Tomato Potato Psyllid (TPP) have made improvements, the incidence of zebra chip in the processing crop has only increased and detection levels in potato fields remains high. CPLI believe the only way to tackle the TPP and Lso (zebra chip) issue in Canterbury, is a Canterbury initiative led by key industry stakeholders, with a purpose to either eradicate Lso and TPP or at the very least to reduce the incidence, so that zebra chip defects have a minimal NZGROWER : APRIL 2022 47
