Dear Trevelyan’s kiwifruit grower,

This weeks Kiwifruit TechTip looks at industry fruit development trends, harvesting at the correct maturity, Gold3 TZG Scale Changes, post harvest Movento, Zespri post harvest nitrogen trial, mainpack clean-up spray options, thinking about harvest and upcoming events.

Industry fruit development trends

This week Abdul Jabbar (Zespri’s Fruit Optimisation Leader) shared two lots of industry insight data from Supplier Monitoring (Gold3) and Supplier data for both Gold3 and HW. In general, both data sets show similar trends:

Smart Monitoring – Gold3 Summary at Week 14

  • Mean fresh weight is 138.9 g with the gain of 1.8g since week 13. Overall, fresh weight seems av.   ̴̴9.8 g higher than 2019 at the same given week.
  • Mean DM is 18.35 % with an increase of 0.43% over one-week interval. By week 14, there is 0.3 % lower DM than 2019.
  • Mean SSC is 8.35 °Brix with an increment of 1.16 °Brix over one week. Lower fractile has reached 6.11 °Brix. On an average SSC seems similar like 2019 by week 14 however higher (1.3 °Brix ) than 2018 and 2017 at the same week.
  • BWFR is 52 %, this is comparable with 2019 at the same week but 4-5% higher than 2018 & 2017.
  • Average °hue is at 103.02 and green fractile of 107.12 °hue. Colour threshold is at 105.22 °hue and this is 1.5 °hue lower than 2019 at the same week.
  • Average firmness is 6.51 kgf (with the loss of 0.11 kgf over one week) and soft fractile is at 5.16 kgf (with the loss of 0.1 kgf over one week) . For 2021 softening curve seems to be setting a bit low firmness trend (on an av. 0.46 kgf less than 2019) and this needs to be observed in coming weeks as softening curve will continue to define.

Gold3 Week 14 Industry Monitoring Comparison

Figure 1. GA Week 13 Industry Monitoring Comparison (data was not collected past Week 12 in 2020 due to Covid-19)

Hayward Week 14 Supplier Monitoring Comparison

Figure 2. HW Week 14 Supplier Monitoring Comparison

 

Supplier Monitoring  – Gold3  Summary at Week 14

  • In suppliers monitoring data mean fresh weight of GA is tracking around an av. ̴137 g
  • Av. DM is 17.63 %. Suppliers monitoring data for GA is also showing 0.3% low DM compared to recent high DM season 2019 yet higher than 2016-18 seasons.
  • Mean SSC is 7.57 °Brix and lower fractile is 5.06 °Brix. In suppliers data, SSC is 0.26 °Brix lower compared to 2019 but 0.4-0.6°Brix higher than earlier seasons.
  • GA flesh colour is developing fine with an average °hue at 102.78, green fractile of 107.33 °hue and colour threshold of 105.16. Overall colour is relatively advanced compared to past seasons.
  • GA fruit is setting a comparatively lower firmness trend with an av. firmness 6.21 kgf and soft fractile of 5.11kgf.

Supplier Monitoring  – HW Summary at Week 14

  • Mean fresh weight is 110.5 g and this is 5-6 g higher than previous seasons at week 13.
  • Mean DM is at 16.33 %. At week 13, DM is 0.28% lower than 2019 while 1% higher than 2018 & 2017.
  • At week 13, mean SSC is at 5.22 °Brix and lower fractile is 4.69 °Brix
  • Average firmness is 8.78 kgf and soft fractile is 7.49 kgf.

As we start the mainpack Gold3 period we continue to carefully watch some of the developing Gold3 trends. Both sets of Week 14 Gold3 data indicate similar fruit firmness trends where average firmness appears to be flattening and coming “more comparable” to previous years. In particular Gold3 fruit this year shows:

  • High brix levels
  • % brix when fully ripe is tracking ahead of previous years (Figure 3)
    • This is a key maturity indicator that Trevelyan’s uses to ensure the maximum storage potential of mainpack fruit is achieved (more detail below)
  • Colour is more advanced (i.e. more gold than previous years)
  • Fruit firmness appears to flattening –  remains  lower than previous years (Figures 4 and 5)

    Figure 3. % brix when fully ripe comparison (Zespri Week 14 SM Update 2021)

    Figure 4. Average fruit firmness comparison (Zespri Week 14 SM Update 2021)       

    Figure 5. Average fruit firmness comparison (Zespri Week 14 Industry Monitoring Update 2021)

    For more detail please see the attached documents:
    Week 14 SM update 2021 (to be added)
    Week 14 Monitoring update 2021 (to be added)

    The importance of harvesting your crop at the ideal maturity

    Everything we do at Trevelyan’s has the grower in mind – our focus is always on achieving the absolute best outcome for the grower.

    As we move into “mainpack” for Gold3 our focus turns to ensuring we can best supply Zespri orders throughout the season – and in particular – at the end of the shipping window. One of the ways to do this is to ensure that mainpack fruit is packed as close to its “optimal maturity” as possible thereby maximising the storage potential of the fruit.

    Better fruit storage translates to lower fruitloss, lower repack charges and maximum storage income for the grower.

    Many rely solely on Zespri’s harvest criteria to determine if the fruits ready to harvest or not, but this criteria is not really measuring fruit maturity – it’s really measuring brix , and brix is really a measure of sugar content – NOT fruit maturity.

    Just because a piece of fruit has lots of sugar, it doesn’t mean it’s mature and ready for harvest. Fruit high in sugar may actually still be immature, and if so will not store to its potential.

    Kiwifruit (along with fruits such as apples, bananas and tomatoes) are climacteric fruit, meaning that they will ripen naturally if they have reached a “tipping point” in their maturity (due to their own ethylene production and respiration). If they haven’t reached this “tipping point”, the fruit will not be able to respire or produce ethylene, and therefore can’t convert starch to sugars. This process is otherwise known as ripening.  Kiwifruit that doesn’t ripen after harvest will eventually turn soft in store before converting enough starch to sugars for it to taste good. Therefore, it is extremely important that the fruit reaches a certain point of maturity that will enable it to ripen and store effectively.

    The hard part is how to predict the level of maturity across your orchard – and what level of maturity makes for a good storing fruit. In recent years we’ve started paying far more attention to “% brix when fully ripe” – a measure that describes how far down the ripening pathway the fruit is – irrespective of brix and dry matter values. We included this measure in our internal harvest criteria guidelines for the 2019 and 2020 season and believe it was a major contributor to Trevelyan’s extremely low fruit loss results over the past two seasons.

    We plan on paying close attention to “% brix when fully ripe” again this season along with other metrics (such as firmness and brix) as part of our harvest conversation. As stated above, early trends indicate that Gold3 % brix when fully ripe is tracking ahead of previous years, and fruit firmness is lower than other years. We will continue to monitor fruit maturity in order to maximise potential of each individual fruit line and make the smartest decisions possible in conjunction with the grower. As per the 2019 and 2020 seasons, this may mean we have to slow down or speed up Gold3 mainpack harvest/packing to align with the fruit maturity.  Its only early days in regards to tracking % brix when fully ripe in Hayward,  but we will also watch this closely aid in harvest and inventory decisions.

    Reminder: Gold3 TZG Scale Changes

    In the NZKGI Weekly Update (16th April 2021) they remind growers that, as a result of the IAC Taste Review, there have been some changes to the TZG scale for Gold 3 Conventional and that you used to achieve for the same dry matter has changed.

    To work out the differences use Figure 6 below: If for example in 2019 you had an average DM of 18.0% you would have achieved a TZG of 0.67. In 2021 the same fruit will only achieve a TZG of 0.59. 

    Figure 6. Old TZG scale v’s new TZG comparison

    NZKGI reports that industry dry matter this season is tracking between 2018 and 2019. At this time of year, industry Dry Matter and TZGs for early mainpack fruit was tracking as shown in Figure 7 below:

    Figure 7. Industry DM and TZG comparison

    High scale at packing? Try a post harvest Movento 100SC application!

    If you are a conventional grower with a problem with scale at packing, consider applying Movento 100SC (960ml/ha) after harvest while leaf condition is good. Adding “Kwicken” (250-500ml/100L) to the tank will improve the uptake of Movento into the leaf, therefore improving efficacy. You’ll need to apply another scale spray in spring but applying Movento now is a great option to reduce scale pressure leading into next season.

    Please note that this application of Movento is considered “off-label” and will require a Justified Approval from Zespri.

    For more detailed information refer to Zespri GET’s “Kiwiflier Spotlight Issue #19 – Postharvest Movento for scale control” document available here.

    Zespri looking for post harvest trial blocks

    The Zespri GET Trials and Data Insights Team is looking for some HW and Gold3 blocks to run a post harvest nitrogen foliar trial. The parameters of the blocks they are looking for are:

    • Low N from leaf tests
    • Main pack GA and/or HW blocks
    • Not strung
    • Strip male and double planted preferred

    If you have blocks that meet these criteria and are open to Zespri conducting a trial on your orchard please contact Vincent Mangin (Trials & Data Insights Specialist – Global Extension Team) at vincent.mangin@zespri.com.

    Clean-up sprays for mainpack crops

    Mainpack crops typically experience more stain than KiwiStart crops. For these tough stains I recommend conventional growers use a phosphate buffered lactic acid products such as Jewel Clean LF or KiwLustre LF as good options. These cleaners act over a period of 2-3 days so a little planning is required for their use, and will have some negative impact on leaf condition.

    If you’re not using a spreader (i.e. Du-Wett° Stainless) apply stain removal products at 1500L water/ha in both directions (total 3000L water/ha) – this ensures good coverage of the fruit and a good clean!

    Organic growers can use Citric Acid at 500g/100L in 1500L water/ha in both directions (total 3000L water/ha).

    Remember that clean-up sprays are ineffective at removing sooty mould or stains caused by heavy metals (i.e. iron or manganese) in your water supply. The best option here is to prevent this type of stain from occurring in the first place by proactively managing PVH/sooty mould prior to harvest and testing your water supply for heavy metal concentrations. If you determine that you have high levels of heavy metals, ensure irrigation heads are lowered so they don’t spray water on fruit. If you use this water for overhead frost protection later in the season, consider using an alternate water source or filtering the impurities from the water.  

    Thinking about harvest…

    Just a few things to think about as harvest is drawing near:

    1. Lift low hanging fruit – anything lower than 1.5m is likely to make contact with sprayers/tractors/harvest bins which can result in cut, split or bruised fruit (affecting your packout, storage and profit).
    2. Check your sprinkler heads – fruit stain caused by irrigation water can be problematic. Irrigation heads that are too high, have been broken and/or knocked sideways can result in water spraying vertically or diagonally, wetting the fruit. Water sources that are high in heavy metals such as iron or manganese may therefore cause staining on fruit. This type of stain can be extremely difficult to remove, with clean-up sprays often being ineffective – so prevention is the best option. Prevent this type of stain from occurring in the first place by ensuring irrigation heads are set level and not too high so water is not making contact with fruit.

    If you identify stained fruit on the orchard try dipping some fruit in clean-up spray (at label rates) to see how effective it is at removing the stain. Remember, not all clean-up sprays work the same way – calcium phosphate/phosphoric acid cleaners such as CP Clean are good options for early harvested fruit, but are less effective at removing heavy staining. Tougher stains may require a phosphate buffered lactic acid product such as Jewel Clean LF or KiwiLustre LF – these cleaners act over a period of 2-3 days but typically have some negative impact on leaf condition (so are not typically recommended for use in KiwiStart).

    I also suggest you contact your Grower Services Rep so we can make a plan around harvest – knowing that fruit may be suffering from stain prior to packing is going to provide you with the best possible outcome!

    3. Enter your fruitset date and spray lines in Spray Diary now – this allows you to run spray diary “test” audits to make sure everything is passing well before harvest (and fix any errors!). Remember to run a “test audit” before your “final audit” – this will let you know if there are any issues with what you’ve recorded. Once you’ve submitted your diary for a “final audit”, your diary is locked and no further changes can be made without contacting Zespri.

    Figure 8. Spray Diary audit buttons – make sure you do a “test” audit before submitting a main audit.

    Feel free to contact me or your Grower Services Representative if you need assistance.

    4. Keep your sward low otherwise the maturity clearance/residue samplers may refuse to access your orchard.

    Upcoming events  

    1. Producer Vote: Zespri Town Halls

    Zespri is organising a series of online town halls to discuss topics relevant to the producer vote. The sessions all start at 6pm and will be moderated by NZKGI.

    • 22 April: The commercial trial and the Zespri brand. Discussion with Zespri’s Chief Growth Officer Jiunn Shih.
    • 29 April: What do the China Advisory Board think? Discussion with Zespri’s China Advisory Board
    • 5 May: How were Driscoll’s successful? Discussion with former Driscoll’s CEO Kevin Murphy
    • 12 May: Trends in fresh produce in China. Discussion with Xavier Naville of China-based Vision Management Consultants
    • 18 May: What does the Chinese consumer think? Discussion with Mark Tanner, Managing Director of Shanghai-based China Skinny
    • 26 May: New Zealand’s relationship with China. Discussion with NZ China Council Executive Director Rachel Maidment

    Growers can submit questions prior to the sessions here.

    For more information and to register, click here.

    1. Emerging Issues for Spray Contractors Meeting – Wednesday 28 April – 5.30pm – 8pm – Zespri Head Office (including buffet dinner)

    The kiwifruit industry is going through a rapid growth period and there is a need to constantly evolve in order to meet the changing conditions. Spray contractors play a vital role in adopting these changes, and as you are on the frontline each day Zespri would love to hear from you about what you perceive the upcoming issues will be for the season ahead.

    Zespri would like to extend an invitation to all spray contractors and your team members to hear about the emerging spray issues for the industry, and provide an opportunity for feedback on these issues ahead of the upcoming season.

    A buffet dinner and drinks will be provided from 5:30pm.

    The key topics of this meeting will include:

    • Explaining the change in spray contractor minimum qualifications (Guest speaker Sue Hawkins of Connexis)
    • Providing up-to-date information on Market Access Protocol and spraying tools for scale
    • Revisiting dormant and early season spray practices including Hi-Cane
    • If you will be joining online we will provide you with a Microsoft Teams link prior to the event.

    Please click here to register your attendance.

    Have a great weekend!