A field study of <i>Bactericera cockerelli</i> feeding timing in potato crops
Since its 2006 detection in New Zealand, the tomato potato psyllid (TPP), Bactericera cockerelli, has been responsible for yield and quality-reducing damage to potatoes as well as to other solanaceous crops. TPP is best known as the insect vector for the zebra chip disease-associated bacterium Candidatus Liberibacter solanacearum (CLso), but feeding by CLso-negative TPP on potatoes is also linked to damaging effects. An improved understanding of which potato plant physiological stages are most affected by feeding of CLso-negative TPP will allow for more directed integrated pest management (IPM) plans. As part of a two-year repeated eld study to assess the effect of TPP feeding timing on potatoes, CLso-negative TPP were released into mesh cages over outdoor potato (‘Moonlight’) plantings at ve different growth stages: post-emergence, owering, post- owering, late-season, and pre-harvest. Tubers were grouped by plant at harvest. (Un)marketable numbers and weights, marketable dry matter and zebra chip severity were determined. Results from this trial and other shadehouse trials conducted previously are still being analysed but have the potential to better target IPM plans and reduce costly, labour-intensive, and environmentally impactful pesticide spray use, which is currently relied on heavily throughout growing seasons.