Improving improving improving
Globally avocados are challenged with biennial bearing, the cause of substantial swings in volume and inherent in the avocado tree. In New Zealand’s cool, windy and wet climate, biennial bearing shifts to a more irregular pattern of fruit production.
Avocados are after all a native of Central America, so our temperate to cold, windy climate does challenge the tree. Our research over the past five years has focussed on how to mitigate this, and canopy management is certainly coming out a strong contender to meet this challenge.
Nearly 40% of avocados are grown in Northland, with the Far North above Kaitaia the least impacted by irregular bearing, with drier, warmer weather. Under our Go Global primary growth partnership, we lead working groups in each region where growers address specific issues. So we are collecting great information from different regions on the practises growers are using on orchard and the impact that has on irregular bearing. This enables us to analyse the impact of weather versus on-orchard practise and the effects of other growing conditions.
We also know growers like to learn in the orchard so continue to improve the field days we host. These are a fantastic opportunity for us as a team to not only share technical information and vital industry updates, but also to engage with our growers.
We recently held field days in Whangarei, the Far North, Katikati and Te Puke. All of them were well attended – in particular the Katikati field day, run in conjunction with Katikati-based packhouse Just Avocados Ltd, where a record 170 growers turned up to enjoy a terrific day, with chairs set out in the sunshine on a gentle slope. The key topic of discussion across the field days was pruning. There was an update on the latest NZ Avocado research and a pretty dramatic pruning demonstration on once very large trees. It will be great to go back in a year’s time and see how those trees reacted to that dramatic pruning, contrasted with the growth of the control trees next door.
We are getting great data and information through the project ‘Avocados for Export’ led by Plant & Food Research and funded by the Ministry of Business, Innovation and Employment. Phillip West leads the trial ‘Pruning to Balance’ which aims to quantify the effects of flower thinning on crop load as a tool to correct
irregular bearing. It is a tool many other tree crops use very successfully and we are working to adapt it to avocados. But in avocados, for every 1,000 flowers only three to five fruit are produced. So every trial we do to measure the impact of flower thinning means we tag up to 12,000 flowers on a tree only to have one tray of about 25 fruit at the end of that trial. It’s tough work.
In the Far North, more orchards are planting or replanting at much closer intervals. Traditionally growers planted at 5m by 5m or 7m by 7m then removed a row of trees to end up with 10m by 10m or even 14m by 14m spacings between trees. Now orchards are planting as close as 3m by 5m, with no intention of removing trees later. Instead there is a huge pruning regime to manage those trees within that space. The advantages of closer plantings is expected to be higher productivity from better light, ease of picking, ability to pick from the ground and efficacy of sprays. The huge opportunity in avocados is driving great innovation right across the industry. It is an exciting place to be.
“The huge opportunity in avocados is driving great innovation right across the industry. It is an exciting place to be.”