3 minute read
Dr Jim Walker: Taking New Zealand apples places
Jim Walker
SCIENTIST FEATURE
The United Nations designated 2021 as the International Year of Fruits and Vegetables, but fruit and vegetables have always been the heart of Plant & Food Research’s business.
By Nickkita Lau : Plant & Food Research
Its innovation and science help growers improve production systems, breed better healthier fruit and vegetables, protect produce from pests and diseases and deliver quality produce to consumers around the world. This article is part of a series to introduce some of the scientists who are working to make that happen.
To Dr Jim Walker and the apple growers that he has been working closely with for the last 40 years, growing nothing short of the best will suffice.
“Everyone in the industry is motivated to grow the perfect fruit and give people what they want. There’s no point growing something substandard, it costs twice as much to pack, ship and market the fruit as it does to grow it.” Perfection means more than the perfect ratio of sweetness to acidity or the perfect crunch. Perfection is grown in one of the most sustainable apple orchard production systems in the world. Other countries have tried, but New Zealand is the only country that has a two-decade long record of successfully exporting apples to Japan, a highly exclusive, premium market with one of the strictest biosecurity requirements for imported apples. While Japan has a zero tolerance policy for the apple pest codling moth, Europe demands negligible chemical residues in contrast. Over the last two decades, the Plant & Food Research team has played a significant role in helping the industry satisfy strict quarantine inspection requirements, and the preferences of different markets with different varieties grown in a production system with the lowest possible agrichemical inputs.
Dr Walker is one of a team of scientists at Plant & Food Research mentored by esteemed integrated pest management ‘guru’ Dr Howard Wearing before they all become experts in their own right.
Their research, struggles and experiences that ultimately led to the industry-wide adoption of their low-input, sustainable pest management programme are documented in Dr Wearing’s book, Farewell Silent Spring – The New Zealand Apple Story. The drive to reduce, maybe even eliminate, all pesticide use is continuous, and the team’s latest work is the development and implementation of the Sterile Insect Technique (SIT) for codling moth, the apple sector’s key pest. Every week they release thousands of sterilised codling moths above apple orchards in Hawke’s Bay using drones and hexacopters. The sterilised moths flood the local populations of wild moths. It means that any eggs from these sterile-wild moth matings are also sterile. The outcome is no viable offspring, which causes the wild moth population to crash over time. The SIT technique is an excellent alternative to pesticides for the control of codling moth. Elimination over large areas is possible, which could negate any justification for chemical fumigation to achieve ‘zero’ risk of codling moth in export consignments. So far it has reduced the wild codling moth population in Central Hawke’s Bay by more than 90%. Already, 60% of New Zealand grown apples are insecticide residue free, while residues on the rest contain less than 10% of the legal limit. The level of residues is so low it is almost equivalent to organic apples. Besides innovations developed by his team, Dr Walker attributes the success in controlling apple pests to the growers who are very willing to adopt new ideas. New Zealand Apples and Pears and the Ministry of Business, Innovation and Employment’s support for research, along with the Ministry for Primary Industries, has also provided an important platform for implementation throughout the sector.
“We have had great cooperation from the growers participating in the SIT project, initially releasing sterile moths through their orchards from mountain bikes, now we are using GPS guided drones and hexacopters to deliver the moths. The SIT programme has continued to expand and now covers approximately 500 hectares of Hawke’s Bay orchards. For an industry of 10,000 hectares, expansion of the programme is the next challenge. Hopefully we can turn it into a national programme one day.”
