Heretaunga Sustainable Water is holding a meeting on Thursday 30th July at the Havelock North Function Centre. It will kick off at 4pm and (as well as incorporating the groups AGM) will provide updates on the work the group has been involved in over the last year. Members and anyone who is interested in becoming a member is encouraged to attend to find out what the group has been doing to try and improve water security on the Heretaunga Plains
Optimising Chemical Thinning: Removing Some of the Magic Arts
Every spring I end up having the same conversation with growers: “Why did thinning work so well in one block and not another?” Or, “The weather looked right, the chemistry was the same—what went wrong?”
The reality is that chemical thinning is often treated as a bit of a magic art. Yet when we step back and analyse the blocks that consistently achieve good crop loads, fruit size and profitability, a pattern emerges. The best outcomes are rarely the result of luck. They are the product of planning, measurement and execution. The more information we collect and use, the less guesswork (magic art) is involved.
Before discussing thinning chemistry, growers need to define what success looks like for each block. That target will vary depending on variety, fruit size requirements, canopy capacity, site limitations and hand-thinning budgets. A crop load that is profitable in one block may be completely wrong for another. The objective is to identify the crop load that delivers maximum return at the desired fruit size and quality.
Once a target is established, everything else should work backwards from it, pruning, flowering assessments, thinning strategy and eventually hand thinning.
One of the biggest opportunities I see is making better use of information growers already have. Review previous seasons and ask:
Historical data helps identify what worked, what did not, and where changes need to be made. Too often thinning programmes are repeated year after year without considering whether the previous result actually matched the target.
Chemical thinning outcomes are largely influenced by four interacting factors:
When thinning results are poor, the answer often lies somewhere within these four areas.
One of the key messages from our work is not to overcomplicate the process. If a programme is consistently delivering good results, do not change it simply for the sake of change. Instead, focus on understanding why it works. Standardise rates, water volumes, surfactants and application methods wherever possible.
Perhaps most importantly, target optimum weather over optimum growth stage. A perfectly timed application applied in poor conditions is often less effective than a slightly later application applied under ideal conditions.
To me, the best chemical thinning you can do is the have boots on the ground. No model or forecast replaces regular orchard observation. The most successful growers are constantly checking blocks, monitoring progress and adjusting plans when conditions change. Chemical thinning should not be a “set and forget” exercise. The orchard is providing feedback every day, it is up to us to listen to it.
Take-Home Message
Crop load remains one of the biggest drivers of orchard profitability. The ability to manipulate crop load early and accurately influences fruit size, quality, labour requirements and ultimately financial returns.
The more disciplined we become around planning, measurement and execution, the less chemical thinning feels like a magic art, and the more it becomes a repeatable management process that consistently delivers profitable outcomes.
Jack Wilson
RMA update:
HortNZ is aware that a number of growers who lodged replacement water take applications last year (or early this year) for consents that expired on 31 May 2026 have recently received emails from HBRC asking them how they want to proceed with their consent applications. Many of these growers are in the Pakowhai area, or take water from the Tutaekuri-Waimate Stream.
We understand there are a number of slightly different emails from the regional council, depending on what has happened in each consent process to date, which is really confusing. We don’t want to add to the confusion by trying to explain things again in a slightly different way, but instead ask people to get in touch with Charlotte Drury on if they want to discuss what might be best in their particular situation
Also please be aware that if you do decide you want to withdraw your application, HBRC is requiring people to fill in a form to complete that process. Here is a link to it: Application-Form-Surrender-Withdrawal-V01-0326.pdf
You should be able to fill it in online, and then you can email your completed form to the consent advisor at consentadvisor@hbrc.govt.nz
Any questions, get in touch with Charlotte Drury (027 3225595 or Charlotte.Drury@hortnz.co.nz)
A bud to fruit ratio is the number of fruit buds in a tree relative to the target number of harvested fruit. Fruit bud numbers directly correlate to the number of floral sites expected in spring and can be used to manipulate vigour status and fruit size outcomes. If not pruning to a target bud number, an understanding of the post prune bud count can guide chemical thinning decisions (how hard they need to go, and the level of floral stress the tree may already be under at flowering).
Bud density and quality are driven by light, varietal tendencies and branch texture. It’s about having the right wood, and good light capture through the tree. Getting to this point without compromising yields may be a 3 to 5 year journey.
As a tree matures and settles, bud numbers tend to increase, particularly in spur varieties. In the spring, flowers acts as a carbohydrate sink when the plant is not photosynthesising, drawing solely on reserves. With a high bud to fruit ratio, the floral stress induces an ethylene spike, resulting in the plant prioritising ‘survival’ over fruit set and influences spring carbohydrate efficiencies. This can help with vigour reduction strategies.
Running a low bud to fruit ratio is a well-utilised strategy in young canopies prioritising growth, or when trying to get a jump on fruit size in spring, particularly in a settled canopy.
There is no hard and fast rule, and not all fruit buds are equal.
Best practice winter bud monitoring includes:
Fruit bud counts: Count all fruit buds regardless of size and shape, including spurs and terminal buds on darts and bourse shoots. For tip-bearing varieties, don’t be tempted to count one-year buds. These are treated as ‘bonus flower’ due to their lower reliability and typically do not produce the highest quality fruit within the tree.
Most growers count buds as a tree average to understand the overall floral load, however splitting the tree into zones allows growers to target buds in specific parts of the tree. Where are the quality buds located and where can we target detail pruning? In a 2D system this could be the target number of buds per wire; in a spindle tree, this could be splitting the tree into bottom, middle and tops. When quantified, this helps refine pruning instructions with confidence that the target cropload will still be achieved.
The budload in the attached photo shows a settled tree with a very high bud density in the tops.
Fruit bud floral capacity assessments: Fruit buds are sampled pre-pruning and assessed under the microscope to determine their floral potential. This is a best-practice winter pruning
metric, helpful on blocks where floral capacity is unknown or on biennial varieties, particularly in an off year. This allows growers to dial their bud to fruit ratio up or down.
Used well, bud to fruit ratios help growers align pruning, thinning and crop load decisions early, giving blocks the best chance of achieving the desired vigour status, target fruit numbers, fruit size and quality.
Meg Becker
There’s plenty happening across the horticulture sector as we head into winter.
Congratulations to Central Otago Young Grower of the Year winner Luke St John, who will now progress to the national final later this year. Closer to home, we’re looking forward to welcoming competitors, sponsors and supporters to the Hawke’s Bay Young Fruit Grower of the Year competition on 18–19 June.
NZAPI has also announced details for its Annual Conference and AGM, taking place in Queenstown on 22–23 July. The conference is a fantastic opportunity to hear industry updates, connect with growers and sector leaders, and discuss the opportunities and challenges facing New Zealand horticulture.
Members can also save the date for the Orchard Research Review on 2 July, which will showcase the latest orchard-based research and provide an opportunity to contribute to future industry priorities.
For more information on these events, conference registrations, industry updates and member resources, visit the NZAPI Members Portal and website.
https://www.applesandpears.nz/
European Canker Best Management – Protecting Leaf Scars.
The recent rain events have created ideal conditions for EC. Soon tens of thousands of leaf scars will be created during leaf fall. It’s important you have a program to protect these wounds from infection. Do not underestimate the impact this disease can have on the economic viability of your orchard. Do not be complacent. It’s an aggressive disease which requires and equally aggressive response.
Best practice includes:
1. Canker walk your blocks NOW. Cut, remove and burn. Lowering the inoculum level in the orchard is the No.1 management tool. You can’t rely solely on spraying your way out of this disease.
2. Commence weekly Captan &/or Copper sprays between 10% and 90% leaf fall. At least 3-4 applications over the leaf fall period. Additional applications will be needed immediately following rainfall events.
3. The Copper & Captan a.i. rates are important for efficacy. Copper a.i. rate is 1.0 kg/ha, Captan a.i. rate is 2.0 kg/ha. Note: do not exceed 5.0 kg Cu/ha/year.
4. Check pH of spray solution. Captan needs buffering to <6.5 to ensure it does not hydrolyse (breakdown).
5. Adjust water rates to achieve complete coverage. Check/test sprayer set-up to ensure even spray deposition. This is crucial for maximum protection.
6. Consider assisted leaf drop sprays, e.g. EDTA Copper, in known high-risk blocks. You must wait until natural leaf has started (~5% leaf fall) before application. Shortening the period that scars from fallen leaves are susceptible to infection reduces the risk of European canker infection. Captan/Copper sprays to cover the wounds is still essential.
7. Do not apply foliar Nitrogen once leaf fall has started. This increases EC infection risk. If Urea is required for black spot clean-up, wait until all leaves have dropped and apply as a 5% solution to the ground.
Note: Sprays are supplemental to an aggressive cutting, removal and burning of inoculum from the orchard.
Dean Rainham, AgFirst Consultants
HAG (Horticultural Advisory Group)
The Heretaunga Sustainable Water (HSW) steering committee continues to meet on a monthly basis to review project updates and set priorities. HSW exists as a forum to advocate and coordinate work that supports long-term (100-year) water security for the Heretaunga plains.
In April the HSW steering committee met with representatives of the Tukituki Water Security project. This project has successfully secured funding to complete feasibility analysis, geo technical testing and design work. Mike Scott, former CEO of Waimea Water has been appointed as CEO for Tukituki Water Security project and Mike Petersen is Chair of the project governance group. The site of this proposed dam is the same as the former Ruataniwha dam proposal but due to changing regulation and other factors, significant changes to the original design of the dam have been undertaken.
The HSW steering committee are also receiving regular updates from the Heretaunga Water Storage project which has selected a site at Whanawhana as a preferred water storage scheme. This project has also been successful in securing funding to advance feasibility analysis including geotechnical and engineering design work and has a governance group including representatives of local government, mana whenua and industry.
Both water storage projects are progressing well at this time and are confident that they can provide viable solutions that will greatly enhance water security on the plains. The HSW steering committee will continue to engage with both project groups as further information becomes available on economic, environmental, technical and cultural factors over coming months. Other project work underway includes analysis of current water abstraction along with 3D models of the aquifer to determine locations where aquifer recharge could be possible. Members of HSW can expect a newsletter update soon including details of an AGM meeting.
Richard Pentreath
Chair of HAG
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NZAPI APPOINTS DANIELLE ADSETT AS CHIEF EXECUTIVE
Decision reflects deep sector knowledge & vision for billion-dollar sector
The Board of New Zealand Apples and Pears (NZAPI) is pleased to announce the appointment of Danielle Adsett as Chief Executive, effective immediately.
Danielle’s appointment reflects her deep knowledge of the pipfruit industry and her future-focused vision for the organisation, its members and the sector.
As Market Access Manager for six years and Acting General Manager since December 2025, Danielle has provided strong and steady leadership along with clear direction and continuity for the organisation.
NZAPI Chair Andrew Gibbs said the Board was unanimous in its decision after a rigorous recruitment process.
“Danielle’s clear vision for the industry, leadership capability, and deep, long-term dedication to the sector were evident throughout the process and made her the standout candidate,” Mr Gibbs said. “We look forward to working with Danielle and the team to deliver further benefits for our members and New Zealand as a whole.”
The announcement comes at a key point in time for the industry, which achieved more than a billion dollars in exports for the first time in 2025, following several challenging seasons marred by weather events and covid-19.
Danielle said she was honoured with the appointment and has hit the ground running.
“I am committed to this sector. Our growers are passionate, innovative and resilient and they produce the world’s best apples.
“I am proud and excited to have the opportunity to support the industry, to advocate on their behalf as we seek to double exports and to work alongside a phenomenal team at NZAPI, who are all equally as committed to our members’ success.”
The Board also acknowledged the tireless work and commitment of former Chief Executive Karen Morrish, who departed at the end of 2025.
NZAPI has now begun recruitment for a Market Access Manager.
Kia ora koutou,
We are looking forward to welcoming students back to Eit in the next few weeks. We have new cohorts starting the Cert in Primary Industry Operation Skills in May, so please get in touch if you have staff needing this entry level qualification. It has a modest fee but also includes Growsafe and First Aid so is great value. Our Level 3 students will be back to study the Growing Environment and Level 4s start on Crop Protection.
Diploma students are still working with their staff to harvest the last of the crop and will return in May to continue their analysis of their research topic. The topics are varied from tree reaction on pruning techniques to chemical application. Cant wait to see the results.
Our 2025 graduates attended the EIT graduation ceremony which was a great success and great way of reaffirming the work, commitment and their achievement over the last two years. Well done Danielle Sammons, Jordan James and Navneet Kaur.
Nutrition Considerations
Throughout the period from post-harvest through to leaf fall, fruit trees are accumulating nutrients and carbohydrates, storing these for use in the following spring. New Zealand’s long growing season provides a distinct advantage for growers as photosynthesis continues to occur well into autumn. This enables carbohydrate production to continue for a longer period in our trees compared to other growing regions. Growers should look to maximise this natural advantage, and make sure their trees enter dormancy with adequate nutrient reserves.
When walking blocks, growers should be sure to take note of foliage colour, tree health, areas of poor growth or any fruit colour problems. This information, coupled with a leaf sample analysis to verify the current nutrient situation will allow the post-harvest nutrition programme to be tailored to the block’s individual needs, and ensure the trees are then set up well for the next season.
Root Health Considerations
Turning the post harvest management attention underground, root health is also an important consideration at this time of the year. Dry roots are not going to be operating at optimum, therefore growers need to ensure blocks have adequate water, for root function, root renewal and nutrient uptake as they move into dormancy. We have quite a range of growing conditions across the Heretaunga Plains, with differences in rainfall, ET, soil type, subsurface hydraulic pressure, therefore a localised understanding of your rainfall and soil moisture status is key.
Flooded root systems will also not be operating at optimum. Therefore, the post harvest period is a good time carry out drainage system maintenance. This helps ensure good root health is maintained prior to potential water logging from winter rainfall events. Poorly maintained drainage (root balls causing blockages, or collapsed tiles) is a limiting factor for root health and resilience. Good drainage allows deep root systems to develop and access underground water reserves, as well as supporting sustainable yields and nutrient uptake.
Sarah McArley, AgFirst Consultants
