Growing Futures

Maintaining quality in the wake of a pest

Maintaining quality in the wake of a pest

Understanding insect pests leads to effective, efficient pest management programmes that maintain quality and reduce pesticide use

Potato is the world’s most important non-grain crop, with global production of 374 million tonnes per year. The New Zealand potato industry produces 586,000 tonnes annually with a value of $570 million. Around 80% of this value comes from domestic sales, whilst the majority of exports are as processed potatoes.

The tomato-potato psyllid (TPP), an insect pest, was discovered in New Zealand in 2006 and has since spread across the entire country. The insect may carry a bacterium, Candidatus Liberibacter solanacearum, which causes the disease zebra chip in the potato tuber and reduces yield and quality of the crop. The New Zealand potato industry has estimated that the arrival of the psyllid cost the industry around 5% of the total value chain in crop losses and control costs.

Very little was known about the tomato-potato psyllid upon its arrival, and producers began crop spraying on a weekly basis in an effort to control the insect and, by association, the zebra chip disease. Under this regime, annual costs associated with the psyllid are estimated at $28 million, including $11 million in crop impact and $6 million in control costs.

Using science to defeat the enemy

Knowledge of the insect’s biology and behaviour has led to the establishment of an integrated pest management (IPM) approach to the psyllid incursion. Spraying regimes based on insect monitoring programmes, combined with the identification of more sustainable chemical controls effective against the insect, are saving the industry an estimated $1 million annually in control costs, as well as significantly reducing the amount of chemical insecticides used on potato fields.

Ongoing research is looking to reduce these costs further through the study of beneficial insects that naturally prey on the psyllid insect and how best to encourage these in the outdoor cropping environment, as well as the development of effective biopesticides that have minimal impact on these existing natural enemies of the psyllid.

Research into the tomato-potato psyllid and its control is funded by the Ministry for Primary Industries' Sustainable Farming Fund, Ministry of Business, Innovation and Employment and Plant & Food Research, with support from Potatoes New Zealand and the New Zealand potato industry.

Created: September 2013

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