True Earth Certified Organics, near Hastings, had to stop supplying potatoes to supermarkets when the tomato and potato psyllid (TPP) ruined yield and crop quality, making it uneconomic to sort good potatoes from poor.
Owner Scott Lawson has since done some basic research crunching the numbers on the Future Farming Centre’s crop net trial at Lincoln.
He’s waiting on the good results to be repeated around the country but is hopeful insect nets will become common, like crop protection in glasshouses and orchards.
Lawson and partner Vicki Meech sell Bio-Gro-certified organic berryfruit and vegetables in the heart of Hawke’s Bay wine country and are one of the biggest producers of certified organic berry fruit and vegetables in New Zealand.
To put potatoes back in supermarkets they would need to consider the cost of buying, installing and maintaining a net, weed control and access to plots for hilling up the crop, Lawson said.
While the insect nets hadn’t been proven it could be a case of growers weighing obvious up-front costs against a hidden cost/benefit.
In the meantime, he was encouraged by the Future Farming Centre escaping blight as a potential side-effect.
The Ministry for Primary Industries says in potatoes the psyllid can reduce the numbers of tubers, size of tubers and production of secondary tubers. Harvested tubers often sprout prematurely but a complicating factor is not all host plants show “toxic” plant reaction symptoms.
In tomatoes, psyllid feeding can cause plants to produce numerous small, poor-quality fruit or prevent fruit forming.