Dear Trevelyan’s kiwifruit grower,

This weeks Kiwifruit TechTip looks at industry fruit development trends, harvesting at the correct maturity, post harvest Movento, Zespri post harvest nitrogen trial, Zespri grower payments booklet, Trevelyan’s 2021 Winter Spray Guides, pre-harvest stain removers/drying fruit quickly, thinking about harvest and upcoming events.

Industry fruit development trends

This week Abdul Jabbar (Zespri’s Fruit Optimisation Leader) shared some industry insights from Supplier Monitoring data at Week 12. In summary Abdul states:

Smart Monitoring – Gold3 Summary at Week 13

  • Mean fresh weight is 137.09 g, this seems   ̴̴5.5 g higher than 2019 at the same given week.
  • Mean DM is 17.92 %, that’s 0.34 % lower than 2019 at week 13..
  • Mean SSC is 7.18 °Brix and lower fractile is 5.53 °Brix. SSC is   ̴0.4 °Brix higher compared to 2019 at the same week 13.
  • Average °hue is at 104.31 and green fractile of 109.14 °hue. Colour threshold is at 107.33 °hue and this is 1.55 °hue lower than 2019 at the same week.
  • Average firmness is 6.62 kgf (with the loss of 0.43 kgf since week 11) and soft fractile is at 5.24 kgf. For 2021 softening curve seems to be setting a bit low firmness trend (on an av. 0.57 kgf less than 2019) and this needs to be observed in coming weeks as softening curve will continue to define

Smart Monitoring  – HW Summary at Week 13

  • Mean fresh weight is 103.78g, with an increase of 6.9 g since week 11. However, HW weight is 3.3g less compared to 2019 at the same week.
  • Mean DM is at 16.74 % with an increase of 0.6% DM in last two weeks. Overall, there is 0.33% higher DM compared to 2019.
  • Mean SSC is at 5.22 °Brix and lower fractile is 4.64 °Brix. Compared to 2019 at week 13, SSC is 0.3 °Brix higher.
  • Average firmness is 9.53 kgf and soft fractile is at 8.06 kgf.
  • Black seed development is at 82% on average however with more than 50% of lines already reached at >90% black seeds

Figure 1. GA Week 13 Industry Monitoring Comparison

Figure 2. HW Week 13 Industry Monitoring Comparison

We continue to carefully watch some of the developing Gold3 trends as they continue to track ahead of previous years and may impact harvest decisions. 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 be lower than previous years (Figure 4)

Figure 3. % brix when fully ripe comparison (Zespri Week 13 Monitoring Update 2021)

Figure 4. Average fruit firmness comparison (Zespri Week 13 Monitoring Update 2021)

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.

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.           

Zespri 2021 Grower Payments Booklet

The 2021 Grower Payments booklet is available here on the Zespri Canopy.

Trevelyan’s 2021 Winter Spray Guides – Conventional and Organic

The Trevelyan’s 2021 Winter Spray Guides for conventional and organic growers are available here on the Trevelyan’s website. Please note that the sprays and timings are suggestions only and the unique circumstances on your orchard(s) may require a different approach to spray management. Not all sprays listed in the Zespri Crop Protection Standard (CPS) have been included, so you may like to consider further options by reviewing this document (found here on the Zespri Canopy website).

Organic/organic conversion growers are reminded that all inputs must also be BioGro™ certified (as well as allowed by Zespri) – please check with BioGro™ that organic status of every input before application

If you have any questions regarding the 2021 Winter Spray Guide, please do not hesitate contacting me or your Grower Representative.

Pre-harvest stain removers

Clean-up sprays are often not required during the KiwiStart period as leaf quality is good and the fruit is not stained from tannins produced as leaves deteriorate later in the season. However, if you choose to use a cleanup spray during KiwiStart:

  • Conventional growers – calcium phosphate/phosphoric acid cleaners such as CP Clean™ are good options for early harvested fruit.
    • Cleaning is completed once the product is dry and apply at of 5L/1000L – applied at 1500L water/ha in both directions (total 3000L water/ha minimum).
  • Organic/conventional growers – citric acid is an effective option (and the only option for organic growers), but there are occasional reports of some stains “re-staining” in coolstore.
    • Apply at 5kg/1000L – applied at 1500L water/ha in both directions (total 3000L water/ha minimum)

Struggling to harvest wet fruit? Du-Wett° and Du-Wett° Stainless may speed up conventional fruit drying times

Laboratory trial data I reviewed in 2019 suggests that the Du-Wett° and Du-Wett° Stainless can speed up drying times on wet fruit. Due to the nature of organosilicone superspreaders, water deposited on the surface of the leaf is spread more evenly and as a thinner film compared to what is normally deposited without the use of a superspreader. This can be extremely useful if your fruit is wet and you’ve got pickers on standby!

Data suggests that in the laboratory, Du-Wett° applied at 1L/ha in 500 litres water nearly halved the time for wet fruit to dry. Observations of growers in the field support this lab data.

If a quicker drying time is required, consider using:

  • Du-Wett° when no stain removal is required
  • Du-Wett° Stainless when a stain removal product is being applied

Don’t forget however, if you plan on putting a sprayer through your orchard immediately prior to harvest, first lift your crop to at least 1.5m above the ground as to minimise contact with the fruit.

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 7. Spray Diary audit buttons – make sure you complete a “main audit” if you’ve asked for spray diary to be unlocked so you could make changes

Trevelyan’s 2021 Winter Spray Guides – Conventional and Organic

The Trevelyan’s 2021 Winter Spray Guides for conventional and organic growers are available here on the Trevelyan’s website. Please note that the sprays and timings are suggestions only and the unique circumstances on your orchard(s) may require a different approach to spray management. Not all sprays listed in the Zespri Crop Protection Standard (CPS) have been included, so you may like to consider further options by reviewing this document (found here on the Zespri Canopy website).

Organic/organic conversion growers are reminded that all inputs must also be BioGro™ certified (as well as allowed by Zespri) – please check with BioGro™ that organic status of every input before application

If you have any questions regarding the 2021 Winter Spray Guide, please do not hesitate contacting me or your Grower Representative.

Pre-harvest stain removers

Clean-up sprays are often not required during the KiwiStart period as leaf quality is good and the fruit is not stained from tannins produced as leaves deteriorate later in the season. However, if you choose to use a cleanup spray during KiwiStart:

  • Conventional growers – calcium phosphate/phosphoric acid cleaners such as CP Clean™ are good options for early harvested fruit.
    • Cleaning is completed once the product is dry and apply at of 5L/1000L – applied at 1500L water/ha in both directions (total 3000L water/ha minimum).
  • Organic/conventional growers – citric acid is an effective option (and the only option for organic growers), but there are occasional reports of some stains “re-staining” in coolstore.
    • Apply at 5kg/1000L – applied at 1500L water/ha in both directions (total 3000L water/ha minimum)

Struggling to harvest wet fruit? Du-Wett° and Du-Wett° Stainless may speed up conventional fruit drying times

Laboratory trial data I reviewed in 2019 suggests that the Du-Wett° and Du-Wett° Stainless can speed up drying times on wet fruit. Due to the nature of organosilicone superspreaders, water deposited on the surface of the leaf is spread more evenly and as a thinner film compared to what is normally deposited without the use of a superspreader. This can be extremely useful if your fruit is wet and you’ve got pickers on standby!

Data suggests that in the laboratory, Du-Wett° applied at 1L/ha in 500 litres water nearly halved the time for wet fruit to dry. Observations of growers in the field support this lab data.

If a quicker drying time is required, consider using:

  • Du-Wett° when no stain removal is required
  • Du-Wett° Stainless when a stain removal product is being applied

Don’t forget however, if you plan on putting a sprayer through your orchard immediately prior to harvest, first lift your crop to at least 1.5m above the ground as to minimise contact with the fruit.

Thinking about harvest…

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

  • 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).
  • 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!
  • 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.

  • Keep your sward low otherwise the maturity clearance/residue samplers may refuse to access your orchard.
  • Understand the new Zespri Maturity Clearance System (MCS) – attend a Zespri training session (online or in person) on how to use/understand the new Zespri MCS – see the “Upcoming Events” section below for more detail.

Upcoming events  

  • Zespri movie screening – A life on Our Planet – Tuesday 13th April – 5.45pm – 8pm – Zespri Head Office

Zespri is hosting an industry screening of Sir David Attenborough’s ‘A life on Our Planet’ at the Zespri Head Office on Tuesday 13 April – doors open at 5.45pm with the movie commencing in the lobby at 6.15pm. Movie duration is 1 hour 54 minutes with a 15 minute intermission at 7.15pm. You are encouraged to stay and chat about what the movie has meant for you and listen to others thoughts.

Click here to register for the event.

  • Emerging Issues for Spray Contractors Meeting – Wednesday 28 April – 5.30pm – Zespri Head Office

Zespri would like to extend an invite to all spray contractors and affiliates to hear about the emerging issues in the industry, and provide an opportunity for feedback on these issues ahead of the upcoming season. This event will start at 5.30pm and dinner and drinks will be provided.

The key topics of this meeting will include:

  • Market Access Protocol and spraying tools for scale
  • Dormant and early season spray practices
  • Change in spray contractor minimum qualifications

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!

Gordon