Avocado Update Research delivers for growers
Collaboration is the theme of our recent research bulletin and it continues to drive our success as an industry.
The bulletin provides a snapshot of current research. With this article are details of some of the exciting results emerging from our research portfolio. This research delivers to our growers and other industry stakeholders the opportunity to contribute to the ongoing work with the aim of maximising the impact our programme has for our industry.
Our research programme aims to increase both yield, in tonnes per hectare, and consistency of yield across seasons. We are tasked with measuring the impact of the research programme on those factors. Across the avocado industry, we benchmark the performance of each orchard on an annual basis and record the improvement in that performance. We record orchard performance as “best”, “good”, and “standard”, based on the four-year average yield and consistency of yield. The chart with this article demonstrates that more than 50% of our orchards now perform in the “good” and best” category, from under 30% in 2010-14.
NZ Avocado is involved in a range of research aimed at delivering tools for our growers to help improve the consistent production of quality fruit. Our research team works collaboratively with scientists from a range of institutes including Plant & Food Research and Waikato University with the help of funding from the ministry formerly known as the Ministry for Primary Industries, Ministry of Business, Innovation and Employment and AGMARDT. With these joint efforts and combined expertise, we are making great progress into not only understanding the needs of an avocado tree better, but also delivering tools that growers can use in their orchard management practices to improve their yields. Some of the key highlights that are emerging from this research include:
The amount of water used by an avocado tree, both young and mature, has been quantified in the Bay of Plenty through monitoring the sap flow in the trunk of the trees. This has led to the generation of a crop factor relating avocado tree water use to reference evapotranspiration. This allows NZ Avocado to publish water use tables fortnightly to growers that can be used to inform irrigation strategies. This work is currently expanding into our other major growing regions, Whangarei and the Far North, to further improve the quality of the data and expand it to the different soil types and conditions.
Avocado trees have a tendency to bear irregularly, a big crop one year followed by a small or even no crop the following year. This provides significant challenges, not only for growers but also throughout the value chain – packers, marketers and even our avocado loving consumers. A significant part of our research programme is aimed at developing tools to address this variation between seasons. One of these tools is flower
pruning to balance crop load in the ‘onyear’ or the big crop year.
The early indications from the flower pruning trials are that flower removal of up to 60% as early as October does not translate to the same drop in final crop – in fact, it is only about a 10% decrease compared with unpruned trees. This flower pruning also results in larger average size fruit and most importantly has an impressive impact on return flower the following season. We are anticipating harvesting the second year’s crop in November; this will allow us to quantify the impact on the return crop from flower pruning in an on-year.
Our canopy-management working group has identified and characterised the pruning strategies of some of the industry’s top pruners. Although many of these pruning strategies differ slightly in their execution, there are some key principles that feature throughout. We have produced an animation highlighting these principles available through our website.
The key principles include pruning to maximise light interception – this is key as growing avocados is all about harvesting light. Pruning to ensure easy access for pickers and spraying allowing for better penetration and coverage. Pruning to cycle wood, ensuring that there is always wood coming through to produce the following seasons flower. Pruning to maximise the health of the tree including balancing the volume of the canopy to the ability of the roots to provide for it.
MATING DISRUPTION FOR LEAF ROLLER
Leaf roller damage to avocado fruit causes it to be rejected for export. One technology that is showing promise for the control of our leaf roller species is mating disruption. Mating disruption uses pheromones unique to the key species we are targeting to disrupt the ability of males to find a mate. A three-year Sustainable Farming funded project developing a unique blend of pheromones is entering its second year of trials. The trials are using pheromone dispensers to validate the efficacy of the pheromone blend to disrupt the mating of all our leaf roller pest species and are showing some very exciting results.
This chart demonstrates that more than 50% of our orchards now perform in the “good” and best” category, from under 30% in 2010-14.