Noncrop host plants prime real estate for the tomato potato psyllid in New Zealand

The tomato potato psyllid, Bactericera cockerelli (TPP), and the bacterium it vectors, Candidatus Liberibacter solanacearum (CLso), are collectively responsible for significant economic losses across New Zealand’s horticulture industry. Crop host plants of TPP include potatoes, tomatoes, capsicums/ chilli peppers, tamarillos and tobacco, along with less-obvious species outside the Solanaceae family, such as kumara (Convolvulaceae). Most of these plants are short-lived summer annuals, which raises the question: what happens to TPP when crops are absent? Many less conspicuous non-crop plants also play host to TPP, some of which are perennial and therefore present year-round, potentially acting as reservoirs of both TPP and CLso in the absence of a crop. A pilot study in 2012 and subsequent vegetation surveys in Canterbury and Hawke’s Bay in 2013-14 confirmed the presence of all TPP life stages on multiple non-crop species year-round in both areas, despite adverse climatic events such as winter frosts and snowfall. These results have far-reaching impacts on the way growers should manage the borders surrounding their crops and their land in the off-season.