Daniel Birnie
Head of Avocado

Operations update

I thought I would compare some of the key YTD stats for this season with previous ones.

• Fruit profile is in line with last season and larger than previous seasons.

• This is the slowest start to the season, as far as I can remember, and definitely for the last five years.

• Local market value has changed. Below is the Size 24 Class 2 fruit value in the July 2 pool over the past four seasons.

With our harvest this season, Trevelyan’s Avocado Growers Limited has asked the avocado team to adhere to the 40% rule as much as possible (that is, only pick 40% of your crop estimate in your first pick). At the beginning of the season, the order of orchards is based on dry matter results; as we get the blanket clearance, we will aim to pick the highest dry matter orchards first whilst also considering orchard location and contractor availability.

Our flowplan is below. As we go through the season, the estimated weekly volumes become actuals, and we smooth out the ups and downs. A number of growers have told us that they plan to wait until the new year to pick. We have 1500 bins estimated for the local market from February onwards. Last season, we did 1100 over the same period.

Katherine Bell
Grower Liaison Representative

AvoGreen rules and how to apply for a Justified Approval

After a monitor is conducted and you have met or exceeded a threshold, you have 28 days to action that monitor. This means you have 28 days to get a spray applied, or you must re-monitor. If you want to spray outside of this 28-day period, you must apply for a Justified Approval through NZ Avocado prior to the spray being applied.

Follow-up Thrip Spray

When the threshold for thrips is exceeded, a second spray can be applied 14-21 days after the first spray without further monitoring. If you need to spray outside of this time for any reason (e.g., weather, spray contractor availability, etc.), you must apply for a Justified Approval before you spray.

Free Leafroller Sprays

One “Market Access” leafroller spray can be applied without a monitor from the 1st of September through to the 31st of October. This can be used prior to bees going into the orchard OR can be used to make a spray application at night, with the permission of the beekeeper. When entering the spray into the Avodiary, you need to select “Market Access LR spray” as your justification.

One leafroller spray may be applied without a formal pest monitor justification from the 1st of November to the 31st of January. In the Avodiary, you need to select “Free Leafroller spray” as your justification.

When leafroller is found during harvest, you may apply a leafroller spray as long as evidence is provided (e.g., photos) and approval is given before spraying. Evidence is to be emailed to dispensations@nzavocado.co.nz. “NZA Justified Approval” can be selected against the spray with the date of the approval email recorded in the comments.

Action thresholds, once met, are justification to spray.

Action thresholds for leafroller:

• 2% or more fruit sites are infested OR
• 2% or more shoot sites are infested.

There is an exception to this where your pre-harvest monitoring result does not meet the threshold for leafroller (e.g. 1%); there is still justification to spray. When entering the spray into the Avodiary, the justification of “Market Access LR spray” is to be selected.

Action thresholds for thrips:

• 2% or more of sites are infested.

A follow-up spray can be applied between 14 and 21 days after the first spray without further monitoring. If you apply a spray outside of this, you need a Justified Approval.

Action thresholds for six-spotted mite:

• Thresholds for six-spotted mite have not been established; they are only suggested. You are justified to spray even with only one mite found on the monitor, although low numbers do not warrant spraying.

Action thresholds for scale:

• If live scale is present at 6% on fruit sites OR
• 4% on leaf sites.

If scale is found post-harvest, you will have it indicated on your packout report. This is a justification to spray once in each of the two peak-crawler-activity periods (Nov-Jan or March-May).

Justified Approval Process

If you need to apply for a Justified Approval, follow this link, which will take you to a page with three options. ‘Agrichemical off-label use’, ‘Delayed spraying’, and ‘Spray application without an AvoGreen justification’.

Agrichemical off-label use-choose this if you want to apply the chemical at a rate that does not match the label or if you wish to apply the chemical for a pest that is not on the label under avocados.

Delayed spraying-choose this if there is a run of severe weather or a spray contractor is not available before the 28 days on your monitor runs out. Apply for this Justified Approval before spraying.

Spray application without an AvoGreen justification-choose this if you wish to spray but have not met the requirements above in the “action threshold section.”

When you click an option to declare the dispensation you wish to apply for, the email template below will pop up. Fill this in and attach the AvoGreen report relating to the spray you want to apply before sending. Wait for an email reply with “dispensation granted” before applying the spray.

If you want to know the withholding periods and rates of certain chemicals, there are a couple of places to look besides the label.

If you go into your spray diary, click “Products” on the left-hand side, and you can search for the chemical. Click the “show market restrictions” button next to the product search bar to find the spray’s withholding period (PHI/Preharvest interval). ‘Maximum applications per season’ or any other spray requirements will be listed under ‘Disclaimer’.

If you’re looking for the registered chemical list for avocados, you’ll find it on the NZ Avocado website in the Quality Manual, Section 3. If you don’t have access to the chemical’s label, this section has what pest each chemical can be used on and other pests that may be affected by the application.

Jonathan Cutting
Avocado Technical Manager

The spring challenges: flowering, starch, pollination and fruit set.

As we enter flowering, I thought it useful to consider some of the challenges around fruit set, particularly fruit set in New Zealand. We are faced with the issues created by low mean annual temperatures, low night temperatures during flowering, long wet periods during flowering and sustaining bee activity in the orchard. Many of our challenges are underpinned by low starch reserves and a climate that results in high levels of floral bias. The literature is full of evidence to support the importance of starch reserves in ensuring good fruit set. I will relay some of the more important information and share how we can use this information to ensure reliable and consistent fruit sets.

South American research from around 10 years ago found that:

“Avocado flowers with a higher starch content in the pistil were found to successfully develop into fruit, whereas those with a low starch content abscised prematurely.”

This goes a long way to explaining the very high incidence of cukes we often observe in New Zealand. We also observe a great deal of metaxenia in New Zealand. This is a most interesting phenomenon. Metaxenia is the effect of a pollen parent on the developing maternal tissues of a seed or fruit outside the embryo and endosperm due to hormones produced by the embryo and endosperm. In simple terms, the act of pollination and pollen tube growth stimulate the start of new fruitlet development. If fertilisation fails, then the fruitlet (which is about match-head-size) stalls and aborts. We see plenty of this in New Zealand. Israeli research noted that integument (the early seed coat) failure in very small avocado fruitlets (that leads to fruit drop) was associated with starch reserves.

Australian researchers found that:

“Accumulated starch is important in supporting flowering when concentrations in the tree rapidly decline; but not so critical for fruit retention and early growth, by which time starch levels are very low.”

This is because reserve starch peaks prior to flowering, and reaches its lowest point after flowering and during early fruitlet growth. Anything that can be done to reduce the rapid drawdown of stored carbohydrates during flowering will have a dramatic and beneficial impact on fruit set and fruit retention. Regular reduction of flowering intensity well before flowering will have significant impacts on yield and fruit size! The opportunity is to explore pruning options in the period from early winter to early flower bud movement.

South African research found that, in Hass:

“Fruit and vegetative growth, along with the normal development of the permanent structures of the tree, require energy and carbon building blocks. The role of starch reserves in supplementing the daily photosynthate production is of vital importance. Low starch reserves at the beginning of a new reproductive season, facilitate an off-year which is often followed by a big yield with small fruit the following season.”

Low cropping years are often associated with a larger fruit size profile and heavy cropping years with a smaller fruit size profile. This would imply a role for carbohydrates in fruit size, most likely from current production rather than from storage.

Australian researchers noted that current season photosynthate was more important in supporting fruit growth in warmer climates and that stored starch plays a greater role in fruit growth in cooler production areas (such as BOP in New Zealand). They concluded that delayed harvest is very destructive to normal starch cycling, reduces yield significantly and initiates alternate bearing cycles.

We cannot consider fruit sets without familiarising ourselves with the uniqueness of avocado flowering. The evolutionary strategy of avocado is to eliminate self-pollination, absolutely minimise close-pollination and heavily favour cross-pollination. Cross-pollination is the transfer of pollen to the Hass stigma from a different avocado variety, such as Ettinger. Close-pollination is when pollen is transferred from a different flower on the same variety. The avocado flower opens twice, once in the female phase and once the following day in the male phase (by which time the female organs in the flower are no longer functional).

Figure 1. Avocado flower in the female phase.

There are two classes of avocado, A and B type. A-type avocados, such as Hass, are functionally female in the morning and functionally male in the afternoon. B-type avocados, such as Zutano, are the opposite; functionally male in the morning and female in the afternoon.

Figure 2. The flower-opening sequence of avocados under “ideal” temperatures – when all the open flowers in a block are considered rather than individual flowers. The green arrows indicate pollen flow.

To shift the pollen from one flower to another requires an insect vector (avocados are not wind or self-pollinated). While there is some speculation on the capacity of a range of small insects (including the hover fly and bumble bees) to act as pollinators, the European honey bee is by far the most recognised and commonly used pollinator in New Zealand. The honey bee is also the only insect that is commercially farmed and sold for pollination services.

The following summary from the Department of Agriculture Western Australia is excellent and concise. The avocado flower provides both pollen and nectar, which will attract the bees, but due to its small size, unusual opening sequence, nectar sacs tucked into the base of the ovary and lower sugar concentration in its nectar, it is not preferred by honey bees. In fact, the ancestral pollinators of avocados were small stingless wasps and flies.

Bees will often be more attracted to other plants flowering at the same time, thus limiting their effectiveness. Bees are known to scout an area to learn where preferred plants are and target these. New bees to an area will not have this knowledge and will target the closest flowers initially, gradually building their knowledge.

To maximise pollination of your avocados, it is preferable to bring in fresh hives at the start of flowering (ideally once roughly 10% of flowers have opened). Do not bring in hives too early as the bees will find other flowers to visit and then when the avocado trees begin to flower in earnest, the bees will remain preferential to the first flowers they found when they were moved into the area.

The amount of pollen deposited, and the number of bee visits have a big impact on successful fertilisation. Israeli research has shown that:

“At least twenty pollen grains or more should reach the stigma to achieve a high fertilization probability. It appears that a cooperative effort of many pollen grains is needed to break through the style and into the ovary. An average of only 1-3 pollen grains are deposited on an avocado stigma by a single visit of a pollen-carrying honey bee. Therefore, more than one visit per flower is necessary to achieve the required pollen amount.”

Figure. 3. Pollen tubes growing in the stigma and style of an avocado flower pistol. PG is pollen grains, S is flower stigma, PT is pollen tubes and ST is stigma.

“In many cultivars, a higher likelihood of fertilisation by outcross pollen, compared to that by self-pollen, was found. Moreover, it appears that pollen of certain cultivars is more potent as a cross-fertilising agent than pollen of others, namely, the formers result in higher fertilisation rates.”

This means that not all polliniser varieties are equal and some cultivars, like Ettinger, are considered “potent”.

Some form of pollen-tube-growth competition is necessary for successful fertilisation, we therefore need many bee visits to each flower. How does this translate into the number of hives and bees required on an orchard? A typical avocado tree has between 40,000 and 100,000 open flowers each day. Assuming 200 trees per hectare, eight bee visits to get 20 grains of pollen per flower and eight bee visits per minute, this equates to 166,000 bees per hectare. Assuming 20,000 foragers per hive gives us a calculated need of eight strong hives per hectare! This is 33-50 % more than the current recommendation of 4-6 hives per hectare.

In summary, the science does provide some areas we can pay attention to and improve fertilisation and fruit set, increase yield and reduce alternate/irregular bearing.

• Managing carbohydrates well and avoiding unnecessary carbohydrate-loss through autumn, winter and especially early spring (flowering). Reduce starch losses through mite and thrips damage as well as autumn flowering and excessive spring flowering. Included here are targeted sprays, abiotic stress-reducing sprays (such as seaweeds), mulching and winter pruning.
• Maximise photosynthate production and starch retention through winter using appropriate frost prevention and leaf chlorophyll support, such as low biuret urea and cytokinin containing seaweed foliar sprays.
• Make sure soil drainage is optimised and trees do not experience unnecessary saturated soil moisture stress.
• Make sure you have adequate numbers of potent pollinisers, such as Ettinger, well-spaced throughout the orchard.
• Keep canopies open and the exterior canopy as illuminated and warm as possible.
• Introduce bees to every block, making sure they are placed in a sheltered location, receiving morning sun and have access to fresh water
• Introduce bees at 10% flowering and make sure that the orchard floor is a flowering sward.
• We are facing an El Nino spring – something we haven’t had for three years! We can expect wind, cool nights, dry orchard conditions and possibly late frosts. I recommend that we plan for them and take the necessary pre-emptive actions.

Spring is a glorious time in the avocado orchard. There is time to appreciate plenty of flowers in healthy, well-balanced avocado trees serviced by plenty of foraging bees.

Enjoy this time as it gets crazy a little later…

Laura Schultz
Grower Liaison Representative

Trevelyan’s Managed Orchards update

Spring has finally sprung, and with that has come our first round of fertiliser applications for the season. Stu has been busy on our Trevelyan’s Managed Orchards, ordering and applying over 15 tonnes of lime in the form of Calciprill. The NZ Avocado Fertiliser Field Days reinforced the importance of calcium at this time of year for robust and high-quality fruit. The first eight weeks after fruit set are essential for calcium uptake.

We have also seen lower levels of boron than usual on soil and leaf tests, so some orchards have received a foliar boron application if the sprayer was going in for an insecticide application around this time – Jonathan recommends applying this at the cauliflower stage, before flowers open (see image below).

Most of our managed orchards have had our contractor apply their second ‘spring’ phosphonate injections in response to the wet conditions of the past year. The first round was applied in autumn.

These phosphonate applications will help support compromised root systems and improve the tree’s ability to resist or recover from phytophthora root rot infection. As we head into flowering and fruit set, we want tree roots to be as healthy as possible for efficient nutrient uptake. Before long, it will be time for bees in, and we will be keeping a keen eye on pollination and fruit set.

Zara Marra
Local Market Manager

Domestic market update – 3rd quarter 2023

• Larger volumes entered the early market this season, bringing extreme pressure on value.
• Export volume is increasing weekly. Low export packouts result in even larger volumes entering the domestic market.
• YTD, the industry has packed 1.3 million Tray Equivalents (TE) compared to 1 million last season.
• Last week saw a record pack volume for the New Zealand market.
• The sunshine, warmer days and summer menu are all positive attributes for the upcoming months.

The graph below shows the comparison between industry volumes and BayFarms returns over the last two seasons.

Class 2 returns per tray for the April – July period.

Sarah Lei
Head of Sustainability

Our 2022 sustainability report

“If the road is easy, it’s probably easy because it’s not a road and you’re not on it.”
Craig D. Lounsbrough

One of the most challenging tasks in my role as Head of Sustainability at Trevelyan’s is writing our annual Sustainability Report. It takes a lot of time and effort to collate the data for the report. This year we have taken a significant step and completed the design of the report in-house, which has added to the complexity of the task.

Despite these challenges, we recognise the importance of sharing our sustainability journey with our stakeholders. We remain committed to publicly reporting our sustainability progress annually, as we have done every year since 2014.

The 2022 Sustainability Report is the ninth report we have produced.

Our 2022 Sustainability Report includes the following:

• The sustainability challenges facing our business and the steps we’re taking to address them.
• Our business performance and our progress towards our sustainability targets.
• Improvements and initiatives we’ve adopted to help achieve our goal of growing a better future.
• Three case studies – sustainable finance, carbon-neutral kiwifruit and showcasing sustainability.

The report has been prepared in accordance with the latest Global Reporting Initiative Sustainability Reporting Standards (GRI Standards) (2021). The GRI Standards are the world’s most widely used sustainability reporting standard.

Our 2022 Sustainability Report can be accessed by clicking on the following link and it will also be emailed out to you in the next couple of weeks. I encourage you to read it and, if you have any comments or questions, please get in touch sarah.lei@trevelyan.co.nz.

Tim Houstoun
Avocado Grower

Where are you based and how long have you grown avocados for?

Based in the Tauranga area. I’ve had an orchard in Welcome Bay for 23 years and on Belk Road for four years.

What do you enjoy most about your orchard/ what’s been the biggest highlight?

I enjoy working outside and seeing the growth that happens on the orchard is rewarding.

What have been the biggest challenges of being a grower?

More compliance over the years and, due to a cold spell one year, we had no income from the orchard.

Can you tell us a little bit about your history?

After 30-odd years of being a diesel mechanic, I became an orchardist with no prior experience, so there has been much to learn.

What do you do in your spare time – do you have any hobbies?

Fishing, tramping, and spending time with my grandkids.

Where do you see your orchard in 10 years’ time?

Employing my grandkids to help on the orchards.

What’s an interesting fact most people don’t know about you?

I attended the World Avocado Congress in Auckland. I know it was expensive, but I gained enough knowledge that it warranted the expense.

Mandeep Kaur Mann
GAP Auditor

Tell us a bit about yourself and your background.

Greetings, my name is Mandeep Kaur Mann, and I was born in Punjab, India.

I immigrated to New Zealand in 1996 at the age of seventeen. Since then, I have been working in the kiwifruit industry, whether that be as a labourer or a grower. My first-ever job was as a packer at Seeka Limited in 1996, and I ended my employment with them as a grading supervisor in 2005. I then joined Eastpack Limited in 2009, holding various positions in the quality department, such as a Quality Controller, Line Quality Manager and GAP Auditor. I currently live in Papamoa, and my husband and I own kiwifruit orchards in Te Puke. We have a seventeen-year-old daughter and a thirteen-year-old son.

What attracted you to work at Trevelyan’s?

When Trevelyan’s had a vacant job position for a GAP Auditor in 2021, I decided to take the opportunity to apply. I was very pleased with my interviewer and was immediately attracted to the friendly and welcoming environment that Trevelyan’s offered.

What is your role and what does it involve?

I began working at Trevelyan’s in September 2021 as a GAP Auditor. My role consists of doing GAP inspections for kiwifruit and avocado growers across the North Island, ensuring growers conform to compliance requirements so they can harvest and sell crops.

When you’re not at work what do you like to do?

I enjoy spending time catching up with my family and friends. I also enjoy participating in my cultural events, watching cricket matches, and visiting the local Sikh Temple every Sunday to worship God.

Shirley Day
AvoGreen Monitor

Tell us a bit about yourself and your background.

I’ve been in the Horticultural industry for 19 years, 13 of those working at Plant and Food Research. Since those years, I’ve completed my AvoGreen training while working with VLS/Seeka after the kiwifruit maturity testing season. Whilst working at Seeka, I was buddied up with three very experienced AvoGreen monitors who gave me a great understanding of the job role.

I’ve worked for Crop Check, adding to my knowledge of identifying beneficial insects. I work part-time for Fruitfed, where I have several tasks, including monitoring, trial work and soil testing.

What attracted you to work at Trevelyan’s?

Trevelyan’s has an excellent reputation throughout the industry, and I’m very proud to be a part of their AvoGreen team as an AvoGreen Monitor,

When you’re not at work what do you like to do?

In my leisure time, you will find me gardening, which I’m very passionate about. Watching the grandchildren play Saturday sports, going for a run or bike ride and upcycling old furniture are also things I thoroughly enjoy.