The correct timing of key orchard management practices is important to acheive high yields of good quality fruit. The information below highlights some key orchard management activities with recommeded timings within each season. Information and links will be reviewed regularly to provide you with the latest information from research trial results, published literature as well as grower and consultant input.

Autumn

Phenology

March – April

  • The leafy canopy continues to extend.
  • Roots will typically flush again with white feeder roots becoming more abundantin the leaf litter.
  • The following seasons floral buds start to become visible and are distinguishable from the vegetative buds by their more rounded apprearance.
  • Some autumn flowering may occur but is usually minor
  • leaves should be a dark green colour.
  • The second and final fruit drop occurs between late March and early April. This, again is a natural adjustment of crop load by the tree.
  • Carbohydrate stores start accumulating once active growth on the tree slows down in later April.

May

  • Trees can start to look dormant but leaves and roots are still active.
  • Fruit continues to size.
  • Carbohydrate stores continue to accumulate to support Spring flowering and growth.

For a video of the phenology of a regular bearing tree, visit the link here.

For a video of the phenology of a irregular bearing tree, visit the link here.

March - April | Prune to manage regrowth

  • Prune to manage regrowth.

    • Regrowth over spring and summer can negate structural pruning carried out in winter to open up canopies.
    • Prune to maintain a more open canopy with good light distribution and spray and picking access.

      • Remove vertical high vigor shoots as these will rapidly shade neighboring limbs.   

      • Remove limbs growing back in towards the middle of the tree as these will create shade and structural issues.
      • Where multiple new shoots have grown as a result of a previous structural cut, consider thinning to two or three shoots to reduce competition with each other.Preferentially select shoots that are growing from the inside of the branch as these are structurally stronger than those growing from the outside and are less likely to break when they become loaded with fruit.

March - April | Inject trees with phosphonate

  • Root test before and 6-8 weeks after injection.
  • If root test results are higher than 90mg/kg roots at 75% moisture don’t inject
  • Expect levels of 25 – 45mg/kg at 75% moisture after injection. Higher is ok.
  • Use 15% working solution of phosphonate and use 20ml of solution per meter of canopy diameter
  • Space syringes evenly
  • Don’t inject sick trees with more than recommended dose. Sick trees have a smaller root mass which acts to concentrate phosphonate. Inject at the same rate as healthy trees.

Further resources on projection of Phytopthrora

March - May | Test soil and leaf nutrients

Leaf testing

  • Ideally sample once summer flush has ceased.
  • Sample youngest mature leaf that has hardened off (Dark green, waxy surface). Sample leaves from shoots that aren’t fruiting or flushing.
  • Collect 4 – 8 leaves from each of 20 trees selected through block or orchard. Ensure leaves collected from the same tree are distributed evenly around the canopy (e.g. from all compass points. North, South, East and West).
  • Seperate samples should be taken from blocks that differe in age, cultivar type, tree performance, soil type and fertiliser history.
  • Try to send samples for analysis as soon as possible after collection.

Soil testing

  • Soil sampling can be carried out at anytime but ideally avoid sampling soon after fertiliser application.
  • 15cm cores should be collected from half way point between the trunk and the drip line of the tree.
  • 1 core from each of 15 – 20 trees should be collected.
  • Seperate samples should be taken from blocks that differe in age, cultivar type, tree performance, soil type and fertiliser history.
  • If trying to diagnose a potential deficiency or toxicity then samples should be collected from the worst affected trees.

To view the Hill Laboratories Avocado crop guide on how to collect samples, visit the link here.

March - May | Review fertiliser plan

  • Combine information from recent soil and leaf test results, crop estimates for this season and historic soil and leaf test results to review your fertiliser plan.

    • Focus on whether the fertiliser plan is adequate for your crop load and whether historc fertiliser applications kept pace with nutrient removal. Can anything be learned by comparing soil and leaf test results from previous seasons with this season’s results?

Ask your fertiliser consultant the following questions:

  • Does my crop load match my fertiliser plan?
  • What are the base soil applications I need to keep up even if I haven’t set a crop on some trees?
  • Based on the crop load I’m seeing, can I reduce applications of some nutrients or do I need to put more on? Nitrogen and Potassium?

A good fertiliser should support the crop load you have not the one you thought you might have. Fruit set becomes visible in early summer and by late summer you have an indication of what proportion of the original fruit set is likely to hold through to harvest.

  • Maintain fertilizer applications 4 – 6 weeks apart and time with rainfall and irrigation. 20 – 30mm of rain or irrigation is a good amount to wash in fertiliser without it draining past the majority of shallow feeder roots.
  • Monitor leaf flush and fruit sizing and contact your fertiliser consultant if you have any questions or concerns about how your trees are progressing.
  • If fruit set is heavier than planned then additional general fertiliser is likley warranted and additional nitrogen fertiliser may be needed to support leaf development.
  • If fruit set is lighter than planned then lower fertiliser inputs are likely required. Reducing nitrogen inputs may help reduce leaf vigour and the amount of pruning required in future.
  • Maturing leaves before winter is the goal as these will be the engines that support next years crop as well as this one.

For more information on nutrients and fertiliser use, click here

Table of nutrient removal with crop harvest (Rosecrance et al, Better Crops, Vol 96, 2012, No 1)

March - April | Monitor soil moisture

  • Ideal mulch depth is 10cm of avocado leaf or coarse mulch material

Use soil moisture monitoring to inform irrigation

Install soil moisture monitoring on the Northern (Sunny) side of a representative tree in the block being irrigated. Probes should be half way between trunk and the drip line of the tree and in a spot that irrigation reaches if the orchard is irrigated.

If using tensiometers such as Irrometer or TenTek brands

  • Use 15cm probe for irrigation trigger (i.e. start irrigation system when readings below are reached)

    • Bay of Plenty = -30kPa
    • Whangarei = -50kPa
    • Far North = -20 to -25kPa

  • Use a 30cm probe to inform sprinkler volume per hour and/or length of irrigation
  • Applying 20 – 30mm of water per irrigation is a good starting point

    • Work out how many mm of water your sprinklers apply using the formula (mm/hour =(sprinkler volume L/hr) ÷(π X radius of sprinkler throw²)
    • e.g sprinkler head delivering 100L/hr with a radius of 4m
    • mm/hr = (100) ÷ (3.142 X 4²)
    • mm/hr = 100 ÷ 50.3
    • 1.99mm/hr
    • So a 100L/hr sprinkler with a throw of 4m radius will deliver 1.99mm of water every 1 hour the irrigation system is run. To deliver 20mm of water the irrigation system would need to be run for 10 hours.

  • If the 30cm probe is drying beyond the trigger point before the 15cm probe → increase volume of water by changing sprinkler head to higher flow rate or irrigating for longer.
  • If the 30cm probe is reading a lot lower than the 15cm probe indicating the soil at 30cm is alot wetter than the 15cm soil →  Decrease volume of water delivered at each irrigation by changing sprinkler head to lower flow rate or irrigate for a shorter period. You may need to increase frequency of irrigation events but decrease the volume of water delivered at each irrigation.
  • Addition of mulch up to acheive a depth up to 10cm will help retain moisture in top 15cm of soil.

For more information relating to, irrigation, optimum use, consent, good management and rules, visit the link here

For free access to Irrigation NZ resources, visit the link here.

Winter

Phenology

June – August

  • The tree may appear dormant but this is the key period when stored carbohydrates are accumulated to support future growth and fruit production.
  • Fruit continue to size at a linear rate.

For a video of the phenology of a regular bearing tree, visit the link here.

For a video of the phenology of a irregular bearing tree, visit the link here.

April - June | Fertiliser planning

  • If you haven’t already done so, combine information from recent soil and leaf test results, crop estimates for this season and historic soil and leaf test results to review your fertiliser plan.

    • Focus on whether the fertiliser plan is adequate for your crop load and whether historc fertiliser applications kept pace with nutrient removal. Can anything be learned by comparing soil and leaf test results from previous seasons with this season’s results?

Ask your fertiliser consultant the following questions:

  • Does my crop load match my fertiliser plan?
  • What are the base soil applications I need to keep up even if I haven’t set a crop on some trees?
  • Based on the crop load I’m seeing, can I reduce applications of some nutrients or do I need to put more on? Nitrogen and Potassium?

A good fertiliser should support the crop load you have not the one you thought you might have. Fruit set becomes visible in early summer and by late summer you have an indication of what proportion of the original fruit set is likely to hold through to harvest.

  • Maintain fertilizer applications 4 – 6 weeks apart and time with rainfall and irrigation. 20 – 30mm of rain or irrigation is a good amount to wash in fertiliser without it draining past the majority of shallow feeder roots.
  • Monitor leaf flush and fruit sizing and contact your fertiliser consultant if you have any questions or concerns about how your trees are progressing.
  • If fruit set is heavier than planned then additional general fertiliser is likley warranted and additional nitrogen fertiliser may be needed to support leaf development.
  • If fruit set is lighter than planned then lower fertiliser inputs are likely required. Reducing nitrogen inputs may help reduce leaf vigour and the amount of pruning required in future.
  • Maturing leaves before winter is the goal as these will be the engines that support next years crop as well as this one.

For more information on nutrients and fertiliser use, click here

Table of nutrient removal with crop harvest (Rosecrance et al, Better Crops, Vol 96, 2012, No 1)

June - September | Structural pruning

Content under construction. Watch this space!

For information relating to canopy management, visit the link here.

June - September | Watch for water logging

Content under construction. Watch this space!

June - August | Irrigation system maintenance

Content under construction. Watch this space!

For free access to Irrigation NZ resources, which include maintenance checklists, visit the link here.

June - November | Frost protection

Content under construction. Watch this space!

For information relating to frost protection, visit the link here.

July - August | Prepare ground for new plantings

Content under construction. Watch this space!

To access the grower manual section relating to orchard establishment, visit the link here.

To access the planting guide, visit the link here.

July - August | Install soil moisture probes

Content under construction. Watch this space!

For information relating to soil moisture management, visit the link here.

For free access to Irrigation NZ resources, visit the link here.

Spring

Phenology

September

  • Flower buds start to swell and develop.

October – November

  • Flowers start to open, are pollinated and fruitlets start to become visible.
  • New red vegetative shoot growth is produced.
  • Roots are often flushing activiely.
  • Carbohydrate stores begin to be depleted to support flower and new leaf development.

For a video of the phenology of a regular bearing tree, visit the link here.

For a video of the phenology of a irregular bearing tree, visit the link here.

August - early September | Inject sick trees with phosphonate to protect trees from Phytophthora

Trees with moderate to severe Phytophothora root rot will benefit from a spring application of phosphonate in addition to the autumn application.

  • Root test before and 6-8 weeks after injection
  • If higher than 90mg/kg roots at 75% moisture don’t inject
  • Expect levels of 25 – 45mg/kg at 75% moisture after injection. Higher is ok.
  • Use 15% working solution of phosphonate
  • 20ml per meter of canopy diameter
  • Space syringes evenly
  • Don’t inject sick trees with more than recommended dose.

Further resources on projection of Phytopthrora

10% flowering | Bring in bees

  • Monitor flowering.
  • Flowers about to open are more rounded compared to those that have already opened.
  • Bring in bees when 10% flowers have opened or earlier.
  • 5-8 hives per hectare. More bees the better.
  • Bees won’t fly in less than 17°C, windy days or very cloudy days.
  • Pollenisers can help with female/male overlap if in marginal climate.

  • Unopened flowers are quite plumb or rounded
  • Flowers that have opened and closed are more pointed
  • Female phase flowers have stamen and anthers more flat against sepals and petal whereas male flowers have more upright stamen and the anthers may have a feathery look as they present the pollen.

September - October | Flower prune excessively flowering trees

Excess crop load reduces return crop with early intervention key to mitigation

For a video about crop load management to reduce irregular bearing, visit the link here.

  • Too much flower is not a good thing but is common if the trees hasn’t held much crop.
  • Allowing the tree to set fruit will deplete value resources that could be used to support fruit sizing, spring leaf flush and next years flowering.
  • The earlier you can prune excess flower off the better but it can be easier to leave until late September/early October when new leaf flush is more visible. This will make it easier to target determinate infloresences that lack new leaf.
  • A balance of 60% determinate and 40% indeterminate is ideal.
Trial tree pruned in October 2015 before flower pruning (left) and after flower pruning (right)

What to target

Cut back to healthy foliage and target flower likely to set fruit in exposed area prone to sunburn and wind damage.

Image on the left shows type of cut made to remove flower panicle. Circled panicles in the image on the right highlight what should be targetted for pruning. This panicle has determinate flower, poor leaf condition, and if it sets fruit, fruit will be exposed to sun and wind making it likely to be low quality.

What to expect

  • Increased fruit size in year 1 with slight drop in yield
Year 1 results of a flower and fruitlet removal trial looking at the effect the timing of crop load reduction has on return crops. Trial was run from 2015- 2017 and was carried out on a Katikati orchard in the Bay of Plenty.

  • Similar fruit size in year 2 with much higher yield from trees flower pruned compared to those that weren’t.

    Year 2 results of a flower and fruitlet removal trial looking at the effect the timing of crop load reduction has on return crops. Trial was run from 2015- 2017 and was carried out on a Katikati orchard in the Bay of Plenty.

November | Apply mulch

  • 10cm is an ideal mulch thickness. Apply additional mulch if exisiting mulch is not adequate.
  • Avocado leaf is best mulch type but chiped avocado pruning is great as well. Coarse wood chip, bark or shelter prunings is ok as well.
  • Any non-avocado material to be used as mulch should ideally be aged for 6 – 12 months before applying to trees.

October - November | Plant trees

  • It’s ok to plant trees anytime if protected appropriately from frost, sun and wind.
  • Review the updated planting guide on how to take deliver of trees, inspect them, plant and care during early development.
  • Plant trees as soon as practical after delivery.
  • Plants will get going once they have recovered from transplant shock and once temperatures are warm enough.
  • Follow planting guidelines and avoid over watering.
  • If replanting avocados into and existing avocado orchard it is storngly advised to replant with a clonal rootstock with tolerance to Phytophthora root rot.
  • SR1 and Latas rootstocks are performing well in Whangarei cultivar trial but perforamnce is unknown in Bay of Plenty and Far North yet.

For more information on the different rootstocks available and their performance in different trials click here.

Ongoing | Monitor soil moisture and use spring irrigation trigger points

  • Ideal mulch depth is 10cm of avocado leaf or coarse mulch material

Use soil moisture monitoring to inform irrigation

Install soil moisture monitoring on the Northern (Sunny) side of a representative tree in the block being irrigated. Probes should be half way between trunk and the drip line of the tree and in a spot that irrigation reaches if the orchard is irrigated.

If using tensiometers such as Irrometer or TenTek brands

  • Use 15cm probe for irrigation trigger (i.e. start irrigation system when readings below are reached)

    • Bay of Plenty = -30kPa
    • Whangarei = -50kPa
    • Far North = -20 to -25kPa

  • Use a 30cm probe to inform sprinkler volume per hour and/or length of irrigation
  • Applying 20 – 30mm of water per irrigation is a good starting point

    • Work out how many mm of water your sprinklers apply using the formula (mm/hour =(sprinkler volume L/hr) ÷(π X radius of sprinkler throw²)
    • e.g sprinkler head delivering 100L/hr with a radius of 4m
    • mm/hr = (100) ÷ (3.142 X 4²)
    • mm/hr = 100 ÷ 50.3
    • 1.99mm/hr
    • So a 100L/hr sprinkler with a throw of 4m radius will deliver 1.99mm of water every 1 hour the irrigation system is run. To deliver 20mm of water the irrigation system would need to be run for 10 hours.

  • If the 30cm probe is drying beyond the trigger point before the 15cm probe → increase volume of water by changing sprinkler head to higher flow rate or irrigating for longer.
  • If the 30cm probe is reading a lot lower than the 15cm probe indicating the soil at 30cm is alot wetter than the 15cm soil →  Decrease volume of water delivered at each irrigation by changing sprinkler head to lower flow rate or irrigate for a shorter period. You may need to increase frequency of irrigation events but decrease the volume of water delivered at each irrigation.
  • Addition of mulch up to acheive a depth up to 10cm will help retain moisture in top 15cm of soil.

For more information relating to, irrigation, optimum use, consent, good management and rules, visit the link here

For free access to Irrigation NZ resources, visit the link here.

Summer

Phenology

December

  • Trees should have multiple clearly visible sites of new red/green vegetative flush about 20cm or longer.
  • Fruit sizes from ‘pin-head’ to pea size.
  • Trees will shed a proportion of fruitlets.
  • Developing fruit and leaves continue to deplete carbohydrate reserves in the tree.

January – February

  • New spring leaves start to harden off to a dark green.
  • Fruitlets size rapidly and begin to hang downwards. They may start to disappear into the growing leafy canopy if there has been sufficient flush.
  • Some fruit will drop through this period. Fruit drop is common as the tree regulates the amount of crop to carry.
  • Carbohydrate stores continue to be depleted through this time.

For a video of the phenology of a regular bearing tree, visit the link here.

For a video of the phenology of a irregular bearing tree, visit the link here.

December - February | Irrigate based on soil moisture monitoring

  • Mulch can help retain soil moisture and reduce the need to irrigate. An ideal mulch depth is 10cm of avocado leaf or coarse mulch material

 

  • Use soil moisture monitoring to understand water needs and inform irrigation.

 

Install soil moisture monitoring on the northern (sunny) side of a representative tree in the block being monitored. Probes should be half way between trunk and the drip line of the tree and in a spot that irrigation reaches if the orchard is irrigated.

If using tensiometers such as Irrometer or TenTek brands

  • Use 15cm probe for irrigation trigger (i.e. start irrigation system when readings below are reached)

    • Bay of Plenty = -25kPa
    • Whangarei = -40kPa
    • Far North = -15 to -20kPa

  • Use a 30cm probe to inform sprinkler volume per hour and/or length of irrigation

    • Applying 20 – 30mm of water per irrigation is a good starting point
    • To work out how many mm of water your sprinklers are applying, use the formula (mm/hour =(sprinkler volume L/hr) ÷(π X radius of sprinkler throw²)
    • e.g sprinkler head delivering 100L/hr with a radius of 4m

      • mm/hr = (100) ÷ (3.142 X 4²)
      • mm/hr = 100 ÷ 50.3
      • 1.99mm/hr
      • So a 100L/hr sprinkler with a throw of 4m radius will deliver 1.99mm of water every 1 hour the irrigation system is run. To deliver 20mm of water the irrigation system would need to be run for 10 hours.

  • If the 30cm probe is drying beyond the trigger point before the 15cm probe → increase volume of water by changing sprinkler head to higher flow rate or irrigating for longer.
  • If the 30cm probe is reading a lot lower than the 15cm probe indicating the soil at 30cm is alot wetter than the 15cm soil →  Decrease volume of water delivered at each irrigation by changing sprinkler head to lower flow rate or irrigate for a shorter period. You may need to increase frequency of irrigation events but decrease the volume of water delivered at each irrigation.
  • Adding mulch to acheive a depth up to 10cm will help retain moisture in top 15cm of soil.

For more information relating to, irrigation, optimum use, consent, good management and rules, visit the link here

For free access to Irrigation NZ resources, visit the link here.

December | Remove excess fruit before end of December

Trees will naturally shed some fruit in December and again around February but removing excess fruit as soon as possible will preserve tree resources for use in fruit sizing, new leaf development and return flowering.

Target

  • Fruit prone to sunburn and windrub

    Fruit pruning being carried out in late December. Exposed fruit being targetted for removal are circled in red.
  • Large bunches that will harbour pests and drain alot of resource
  • Areas of slow leaf flush

Outcome will be

  • Improved fruit size if done early enough
  • Better leaf coverage to protect remaining fruit
  • Better return flowering

For a video about crop load management to reduce irregular bearing, visit the link here.

December - February | Review fertiliser plan

Ask your fertiliser consultant the following questions:

  • Does my crop load match my fertiliser plan?
  • What are the base soil applications I need to keep up even if I haven’t set a crop on some trees?
  • Based on the crop load I’m seeing, can I reduce applications of some nutrients or do I need to put more on? Nitrogen and Potassium?

A good fertiliser should support the crop load you have not the one you thought you might have. Fruit set becomes visible in early summer and by late summer you have an indication of what proportion of the original fruit set is likely to hold through to harvest.

  • Maintain fertilizer applications 4 – 6 weeks apart and time with rainfall and irrigation. 20 – 30mm of rain or irrigation is a good amount to wash in fertiliser without it draining past the majority of shallow feeder roots.
  • Monitor leaf flush and fruit sizing and contact your fertiliser consultant if you have any questions or concerns about how your trees are progressing.
  • If fruit set is heavier than planned then additional general fertiliser is likley warranted and additional nitrogen fertiliser may be needed to support leaf development.
  • If fruit set is lighter than planned then lower fertiliser inputs are likely required. Reducing nitrogen inputs may help reduce leaf vigour and the amount of pruning required in future.
  • Maturing leaves before winter is the goal as these will be the engines that support next years crop as well as this one.

For more information on nutrients and fertiliser use, click here

Table of nutrient removal with crop harvest (Rosecrance et al, Better Crops, Vol 96, 2012, No 1)
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