Ambrosia Fruit Maturity Report - Oct 15

Tuesday, October 15, 2024

This update on Ambrosia will be the final maturity report for the season. In the regions being monitored, Ambrosia is in the midst of harvest maturity. Situations of lower-than-target crop load encourage early ripening. After the start of harvest maturity there is a window of time before those fruit ripen beyond starch index 4.5 that is recommended for storage purposes. Using Harvista at one of the example sites may have helped to delay ripening as shown by the relatively slow rate of starch conversion (however we don't have an untreated comparison so this is speculation only).

I would like to say a huge THANK YOU to the farms that have agreed to be the long-term monitoring sites for industry-wide updates on maturity. It is always my wish that you all have a good crop of quality fruit. You have all worked so hard and as harvest continues I just want to take a moment to say you're doing great work!!!

Important Note - The following information about maturity is for general industry purposes only. Growers are encouraged to use their own discretion to harvest trees that are exhibiting delayed colour development or exhibiting maturity indices that disagree with what is being reported here. Values were measured on an average of fruit that were representative of the block's crop load and tree vigour. Fruit representative of size and colour were taken from all sides of the tree.

Ambrosia Fruit Maturity Report

Fruit were taken from throughout the trees to target a one-pick harvest to strip the trees.

Table 2: Maturity indices for Ambrosia fruit sampled in the current year on Tuesday, Oct 15 2024. Values are compared with the samples taken last week on Oct 7 to estimate a weekly rate of change. Please note that in Lakeville the bottoms of the trees were harvested so the values represent remaining fruit on tree tops.

Table 2 Discussion:

Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage of Ambrosia are between 2.8 and 4.5. When harvested late, the fruit are at greater risk of developing greasiness, rot, core flush, and senescent breakdown in storage.

In the regions being monitored, the starch index values for Ambrosia are in the midst of the window of harvest maturity.
The starch index value is showing a rate of change of +1.4/wk in fruit that had reached maturity the week prior, representing a faster rate of change than what was observed previously.
The Lakeville region that was treated with Harvista at about 1 week before anticipated harvest was harvested in the tree bottoms prior to the wind. The treated fruit remaining in the treetops does appear to have a relatively slower rate of change of starch index, being only +0.5 over the last week. The Harvista was applied 11 days ago. It may have bought some time as anticipated.

The DA value appears misaligned so starch index should be monitored.
Soluble solids values in our region for Ambrosia tend to be 12% at around optimum harvest maturity but again it depends on crop load. The soluble solids are currently optimal or higher in the regions being monitored.
Where there is advanced starch movement and above-average soluble solids representing sugar content in the regions being monitored, it is due in part to lower-than-target crop load.

More observations (data not shown):

Red colour is very good on the sun exposed side and as is typical of Ambrosia the shade side is yellow.

The fruit size in my samples averaged 226 g which is slightly larger than last week. The diameter is fairly similar to last week at an average of 79 mm/3.11 inches. However, this information is highly dependent on the crop load in a particular block.
It appears as though a small percentage of Ambrosia fruit was lost to the windstorm on the weekend. Hopefully less than what was anticipated.

About each maturity measurement:

Starch Index - Starch is converted to sugars as ripening progresses. The starch-iodine test is used because iodine binds to starch molecules turning them blue/black, whereas sugars are not stained and remain clear. The Cornell chart on a scale of 1 to 8 was used above and values are an average of ten representative samples from each block.

Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block.

DA Meter - The delta absorbance (DA) value is related to the chlorophyll content of the peel. AAFC researchers in Kentville developed a protocol for Honeycrisp and Ambrosia.

For Honeycrisp, values above 0.60 are immature, values 0.6 to 0.36 are ideal for long term storage, and values below 0.35 are best for short term storage because they are more prone to storage disorders.
For Ambrosia, values above 0.47 are immature, values 0.47 to 0.28 are ideal for long term storage, and values below 0.28 are best for short term storage because they are more prone to storage disorders.
Values shown above are the average of twenty fruit taken throughout a block, with readings taken on the transition area between the sun and shade exposed sides. DA values will be noticeably different between the most mature and least mature fruit on a tree.

Notices

NSDA Programs

Programs staff would like to inform clients that applications are being accepted at this time for the following 2024-2025 programs. Programs for the 2024-2025 year, along with their applications and guidelines can be found by clicking the following links:

Market Opportunities and Diversification – Deadline October 24th
Speaker Series Assistance Program
Plant your Roots
Organic Certification Rebate Program
Agriculture Skills Student Bursary Program

For more information on these programs please contact your local Ag Rep.

Nova Scotia Loyal Program

Did you know that as a local producer and/or retailer, you are eligible to apply to become an official partner in the government of Nova Scotia’s buy local program, Nova Scotia Loyal?

This program is helping build demand for and consumption of local products and putting more money directly into the hands of local producers. You can register to participate in the program by visiting www.nsloyal.ca.

Registration will provide you with access to program materials and marketing assets to make it easier for consumers to identify and find local products. Additionally, you have the option to participate in a retailer directory designed to connect producers and retailers to increase the number of Nova Scotia products on retailer shelves.

Should you have any questions about the program, please contact: novascotialoyal@novascotia.ca

Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist

Honeycrisp and Ambrosia Fruit Maturity Report - Oct 7

Monday, October 7, 2024

Maturity updates are wrapping up for the remaining Honeycrisp fruit (treated with ReTain) and therefore the majority of this update focuses on Ambrosia fruit. In Ambrosia, harvest maturity approaches or may have begun depending on the crop load of a particular block. When harvest maturity begins there is a window of time before fruit are considered overmature for storage purposes (see the post for estimates on the rate of change of the starch index). The Ambrosia sugar content represented by soluble solids has reached optimal values.

Honeycrisp Fruit Maturity Report

The following Honeycrisp information represents the remaining fruit where maturity is slightly delayed relative to first-pick fruit.

Table 1: Maturity indices for regular Honeycrisp fruit sampled in the current year on Monday, Oct 7 2024. Where possible, values are compared with the samples taken last week on Oct 1 to estimate a weekly rate of change.

Table 1 Discussion:

Fruit treated with ReTain at 3 weeks prior to expected harvest that remain after the first-pick are still within optimal maturity. They are not overmature as they have not exceeded starch index value of 7.5. Late harvest beyond starch 7.5 results in fruit in storage with more soft scald.
Soluble solids values in our region for Honeycrisp tend to be 11% at around optimum harvest maturity but it depends on crop load.

Ambrosia Fruit Maturity Report

Fruit were taken from throughout the trees to target a one-pick harvest to strip the trees.

Table 2: Maturity indices for Ambrosia fruit sampled in the current year on Monday, Oct 7 2024. Values are compared with the samples taken last week on Oct 1 to estimate a weekly rate of change.

Table 2 Discussion:

Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage of Ambrosia are between 2.8 and 4.5. When harvested late, the fruit are at greater risk of developing greasiness, rot, core flush, and senescent breakdown in storage.

Starch index values are now within the window of harvest maturity in the example region in Rockland and are nearing the start in Lakeville and North Medford.
The starch index value is showing a rate of change of +0.7 wk in areas untreated with Harvista. There will be a window of opportunity before the fruit exceed starch index 4.5. According to the current rate of change, the harvest maturity window could be 2 weeks.
The Lakeville region that was treated with Harvista at about 1 week before anticipated harvest does appear to have slowed down in the rate of change of starch index, being only +0.3 over the last week. It may have bought some time.

Similar to the DA value in the context of Honeycrisp, there is a misalignment with Ambrosia so starch index should be monitored.
Soluble solids values in our region for Ambrosia tend to be 12% at around optimum harvest maturity but again it depends on crop load. The soluble solids are currently optimal in all regions being monitored.
Where there is advanced starch movement and above-average soluble solids representing sugar content in the regions being monitored, it is due in part to lower-than-target crop load.

More observations (data not shown):

Red colour is averaging around 57% on the entire tree for a one-pick harvest.

The fruit size in my samples averaged 220 g and is fairly similar to last week. The diameter was an average of 79 mm/3.11 inches and is similar to last week. However, this information is highly dependent on the crop load in a particular block.

Table 3: Maturity indices for Ambrosia fruit relative to samples taken last year on Oct 10, 2023.

Table 3 Discussion:

Starch index is higher this year meaning that maturity is slightly ahead.
Soluble solids vary, likely related to crop load.
The DA meter values are lower this year meaning that the DA meter also predicts advanced maturity but note comments above about possible misalignment of actual DA values with actual fruit maturity.

About each maturity measurement:

Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block.

DA Meter - The delta absorbance (DA) value is related to the chlorophyll content of the peel. AAFC researchers in Kentville developed a protocol for Honeycrisp and Ambrosia.

For Honeycrisp, values above 0.60 are immature, values 0.6 to 0.36 are ideal for long term storage, and values below 0.35 are best for short term storage because they are more prone to storage disorders.
For Ambrosia, values above 0.47 are immature, values 0.47 to 0.28 are ideal for long term storage, and values below 0.28 are best for short term storage because they are more prone to storage disorders.
Values shown above are the average of twenty fruit taken throughout a block, with readings taken on the transition area between the sun and shade exposed sides. DA values will be noticeably different between the most mature and least mature fruit on a tree.

Notices

NSDA Programs

Young Farmer Mentorship Program – Deadline October 8th
Market Opportunities and Diversification – Deadline October 24th
Speaker Series Assistance Program
Plant your Roots
Organic Certification Rebate Program
Agriculture Skills Student Bursary Program

For more information on these programs please contact your local Ag Rep.

Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist

Honeycrisp and Ambrosia Fruit Maturity Report - Oct 2

Wednesday, October 2, 2024

Maturity updates continue for the remaining Honeycrisp fruit after the first-pick including those treated with ReTain or not, in the example regions. The remaining Honeycrisp fruit are relatively less mature than first-pick fruit but are still at or near maturity and may just require more red colour to develop. In Ambrosia, starch conversion to sugars continues and fruit approach the start of harvest maturity in some situations, especially in historically early blocks and those with low crop load.

Honeycrisp Fruit Maturity Report

The following Honeycrisp information represents the remaining fruit where maturity is slightly delayed relative to first-pick fruit. The rate of change is not stated where fruit were picked between this week and last week's measurements. The Lakeville rate of change represents the change in maturity of the remaining fruit because those same fruit were reported last week.

Table 1: Maturity indices for regular Honeycrisp fruit sampled in the current year on Tuesday, Oct 1 2024. Where possible, values are compared with the samples taken last week on Sept 23 to estimate a weekly rate of change. Please note that new factors are introduced this week including first pick in Rockland and North Medford.

Table 1 Discussion: There are many factors at play but here's what I can glean for general guidance...

Fruit remaining after the first-pick of 60-75% in the example regions are not overmature as they have not exceeded starch index value of 7.5.

In the Lakeville example, the remaining fruit without ReTain may have only one more week until they become overmature for long-term storage.
In Rockland, there is no untreated comparison but ReTain applied 1 week before anticipated harvest may have slightly delayed the maturity of the remaining fruit.
Where ReTain was used 3 weeks before the anticipated harvest in North Medford, starch index values of the remaining fruit are relatively low near 4, seemingly offering some additional time to harvest.
Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage for Honeycrisp are between 5.0 and 7.5. Early harvest of Honeycrisp before starch 5.0 can lead to more bitter pit in storage whereas late harvest beyond starch 7.5 results in more soft scald.

DA meter values are not consistently aligned with starch so refer to starch comments above. The rate of change is different in ReTain-treated fruit so the standard DA meter values for optimum maturity do not apply to ReTain-treated fruit.
Soluble solids values in our region for Honeycrisp tend to be 11% at around optimum harvest maturity but it depends on crop load. The soluble solids of the remaining fruit are near-optimal.
Crop load always has an influence. More vegetation relative to less crop will result in more resources for colour and advanced maturity. The crop load in the blocks being monitored is slightly lower than target.
It becomes increasingly difficult to make historical comparisons as harvest progresses because of the variable factors like ReTain and first pick dates/percentages. However, it appears as though starch index continues to be higher at this point in time when compared to 2023, meaning that maturity is ahead.

More observations (data not shown):

Red blush colour on the fruit remaining after first-pick currently averages 45-50%. In Lakeville the fruit remaining after first pick increased in colour by 10% over the last week. Two sites were treated with ReTain so the product may influence colour if maturity is also delayed.
The fruit size across my samples averaged 238 g and 81 mm/3.2 inches in diameter. In Lakeville, the remaining fruit grew at a rate of +11.5g/wk and +0.7 mm(0.03")/wk. However, this information is highly dependent on the crop load in a particular block.

Ambrosia Fruit Maturity Report

Fruit were taken from throughout the trees to target a one-pick harvest to strip the trees.

Table 2: Maturity indices for Ambrosia fruit sampled in the current year on Tuesday, Oct 1 2024. Values are compared with the samples taken last week on Sept 23 to estimate a weekly rate of change.

Table 2 Discussion:

Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage of Ambrosia are between 2.8 and 4.5. When harvested late, the fruit are at greater risk of developing greasiness, rot, core flush, and senescent breakdown in storage.

Starch index values are nearing 2.8 in some of the example regions and there will be a window of opportunity before the fruit exceed starch index 4.5.
The starch index value is showing a rate of change of +0.5 to +1.0/wk. The fastest rate of +1.0/wk appears in conjunction with the fruit of advanced maturity. The current rate of change suggests a 2-week window and updates will be given next week.
If labour issues are anticipated, Harvista may be an option on up to 3 days before harvest.

Similar to the DA value in the context of Honeycrisp, there is a misalignment with Ambrosia so starch index should be monitored.
Soluble solids values in our region for Ambrosia tend to be 12% at around optimum harvest maturity but again it depends on crop load. The soluble solids are currently optimal in the Rockland and Lakeville example regions.
Where there is advanced starch movement and good sugar content in the regions being monitored, it is due in part to lower-than-target crop load.

More observations (data not shown):

Red colour is averaging around 45% on the entire tree for a one-pick harvest.

The fruit size in my samples averaged 223 g and growing at a rate of +16g/wk. The diameter was an average of 79 mm/3.11 inches and growing at a rate of +2 mm/+0.08 inches/wk. However, this information is highly dependent on the crop load in a particular block.

About each maturity measurement:

Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block.

DA Meter - The delta absorbance (DA) value is related to the chlorophyll content of the peel. AAFC researchers in Kentville developed a protocol for Honeycrisp and Ambrosia.

For Honeycrisp, values above 0.60 are immature, values 0.6 to 0.36 are ideal for long term storage, and values below 0.35 are best for short term storage because they are more prone to storage disorders.
For Ambrosia, values above 0.47 are immature, values 0.47 to 0.28 are ideal for long term storage, and values below 0.28 are best for short term storage because they are more prone to storage disorders.
Values shown above are the average of twenty fruit taken throughout a block, with readings taken on the transition area between the sun and shade exposed sides. DA values will be noticeably different between the most mature and least mature fruit on a tree.

Notices

NSDA Programs

For more information on these programs please contact your local Ag Rep.

Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist

Honeycrisp and Ambrosia Fruit Maturity Report - Sept 24

Tuesday, September 24, 2024

This is the fifth maturity update for Honeycrisp and the first update for Ambrosia using the example regions. The Honeycrisp fruit being monitored are within the window of optimal maturity. Soluble solids that represent sugars are higher this year relative to last year. ReTain-treated fruit are delayed in maturity as expected. In Ambrosia, some minor starch movement and good sugar content is reported especially in cases of lower-than-target crop load. If labour issues are anticipated, ReTain or Harvista may be considered.

Honeycrisp Fruit Maturity Report

Only when the first-pick already occurred were second-pick fruit sampled from the interior of the canopy, where maturity is expected to be delayed.

Table 1: Maturity indices for regular Honeycrisp fruit sampled in the current year on Monday, Sept 23 2024. Values are compared with the samples taken last week on Sept 16 to estimate a weekly rate of change. Please note that new factors are introduced this week including ReTain at the Rockland site and first pick in Lakeville.

Table 1 Discussion:

First-pick fruit are optimally mature for long term storage at starch index values that are now around 5.0 at the monitoring region in Rockland.

In Rockland, it is unlikely that the ReTain influenced the maturity of the first pick fruit but should influence later picks.
Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage for Honeycrisp are between 5.0 and 7.5.
Early harvest of Honeycrisp before starch 5.0 can lead to more bitter pit in storage whereas late harvest beyond starch 7.5 results in more soft scald.
Where ReTain was used 3 weeks before the anticipated harvest in North Medford, starch index values are relatively low near 3 after a slow increase from last week.

DA meter values have changed little over the last week and starch index values have caught up to align better with DA meter predictions for optimal maturity.

However, the ReTain-treated fruit are not yet mature according to the starch index, meaning that the DA meter value is misaligned with ReTain treatments. The DA meter was developed as a tool based on the relationship between chlorophyll degradation and the rate of change of maturity indices. The rate of change is different in ReTain-treated fruit so the standard DA meter values for optimum maturity do not apply to ReTain-treated fruit.

Soluble solids values in our region for Honeycrisp tend to be 11% at around optimum harvest maturity but it depends on crop load. The soluble solids are currently optimal.
Crop load always has an influence. More vegetation relative to less crop will result in more resources for colour and advanced maturity. The crop load in the blocks being monitored is slightly lower than target.
It becomes increasingly difficult to make historical comparisons as harvest progresses because of the variable factors like ReTain and first pick dates/percentages, but the following can be gleaned.

Starch index continues to be higher at this point in time when compared to 2023, meaning that maturity is ahead. However, the North Medford block that was treated with ReTain last year and this year at 1/2 rate on Aug 29 is maturing at a very similar rate to 2023.
All regions have fruit with higher sugar content this year relative to last year.

Where labour issues are anticipated, Harvista may be applied to temporarily halt maturity progression on first or second picks (ideally when starch index is 4.0 to 6.0). At this time, ReTain should only be considered if the block is 1 week or more away from harvest maturity in order to delay maturity of the later picked fruit. The preharvest strategy table is available on our website.

More observations (data not shown):

Red blush colour is progressing well this year overall, however, only a minor increase was recorded over the last week.

Fruit treated with ReTain generally have less colour but are also correspondingly at an earlier stage of maturity.

The fruit size across my samples averaged 220 g and growing at a rate of +5.5g/wk. The diameter was an average of 79 mm/3.11 inches and had stayed relatively constant over the last week. However, this information is highly dependent on the crop load in a particular block.

Ambrosia Fruit Maturity Report

Fruit were taken from throughout the trees to target a one-pick harvest to strip the trees.

Table 2: Maturity indices for Ambrosia fruit sampled in the current year on Monday, Sept 23 2024.

Table 2 Discussion:

The starch has begun to convert to sugars so the starch index is higher than the base level of 1.0. Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage of Ambrosia are between 2.8 and 4.5. Starch index values are currently below 2.8.

When harvested late, the fruit are at greater risk of developing greasiness, rot, core flush, and senescent breakdown in storage.
ReTain may still be applied this week or next if labour issues are anticipated, and Harvista is an option on shorter-notice.

Similar to the DA value in the context of Honeycrisp, there may be a misalignment with Ambrosia so starch index should be monitored. Updates will be provided next week.
Soluble solids values in our region for Ambrosia tend to be 12% at around optimum harvest maturity but again it depends on crop load.
Where there is already minor starch movement and good sugar content in the regions being monitored, it is due in part to lower-than-target crop load.

More observations (data not shown):

Red colour is averaging around 20% on the entire tree for a one-pick harvest.

Remember that if colour is progressing better than it has in recent years, just be cautious about harvest maturity. In some cases high colour encourages harvest of immature fruit.

The fruit size in my samples averaged 207 g. The diameter was an average of 77 mm/3.03 inches. However, this information is highly dependent on the crop load in a particular block.

About each maturity measurement:

Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block.

DA Meter - The delta absorbance (DA) value is related to the chlorophyll content of the peel. AAFC researchers in Kentville developed a protocol for Honeycrisp. For Honeycrisp, values above 0.60 are immature, values 0.6 to 0.36 are ideal for long term storage, and values below 0.35 are best for short term storage because they are more prone to storage disorders. For Ambrosia, values above 0.47 are immature, values 0.47 to 0.28 are ideal for long term storage, and values below 0.28 are best for short term storage because they are more prone to storage disorders. Values shown above are the average of twenty fruit taken throughout a block, with readings taken on the transition area between the sun and shade exposed sides. DA values will be noticeably different between the most mature and least mature fruit on a tree.

Notices

NSDA Programs

Market Opportunities and Diversification -*Newly Opened
Limestone Trucking Assistance Program Application Deadline: September 30, 2024
Get Growing Program - Application Deadline: September 30, 2024
Young Farmer Mentorship Program *Extended Application Deadline: October 8, 2024, the website will reflect this change shortly*
Speaker Series Assistance Program
Plant your Roots
Organic Certification Rebate Program
Agriculture Skills Student Bursary Program

For more information on these programs please contact your local Ag Rep.

Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist

Honeycrisp Fruit Maturity Report - Sept 17

Tuesday, September 17, 2024

This is the fourth maturity update for Honeycrisp using the example regions. At the current rate of change, first pick fruit are expected to be optimally mature in a few days' time at the example regions being monitored. An update is shared on the rate of change of starch, sugars, colour, mass and diameter etc. Please note that the DA meter is misaligned with maturity indices this year and that the tool is predicting maturity prior to actual maturity. Please refer to the update for more details.

Weather

Degree Day Accumulations

Total degree day accumulations are still slightly warmer than average and the trend has not changed significantly in recent weeks. This year ranks in the top few years of heat accumulation in the historical record. Interestingly, even though the overall growing season has been above-average, August temperatures have been on average. In August, temperatures did not exceed 30°C and therefore did not impede colour development. Also, below average nighttime temperatures and many sunny days may be contributing to good fruit colouration.

Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to September 15 for the past 17 seasons. Provided by Jeff Franklin (AAFC).

Approximately 4% more plant development heat units compared to the 5-year average, and 4% more compared to the 10-year average.
Approximately 3% more plant development heat units compared to 2023, and 1% less compared with 2022.
Approximately 4% more insect development heat units compared to the 5-year average, and 5% more compared to the 10-year average.

Seasonal Precipitation

The precipitation events have been erratic with a few large precipitation events contributing much of the total. The precipitation total is average but likely some of the rainfall was lost as runoff.

Figure 2: Monthly precipitation totals in 2024 compared with the 10-year average. Provided by Jeff Franklin (AAFC) using the Kentville weather station data.

Honeycrisp Fruit Maturity Report

Important Note - The following information is for general industry purposes only. Growers are encouraged to use their own discretion to harvest trees that are exhibiting delayed colour development or exhibiting maturity indices that disagree with what is being reported here. Values were measured on an average of fruit that were representative of the block's crop load and tree vigour. Fruit representative of size and colour were taken from all sides but not from the interior of the canopy where maturity is expected to be delayed and is most likely targeted for a second pick timing.

Table 1: Maturity indices for regular Honeycrisp fruit sampled in the current year on Sept 16, 2024. Values are compared with the samples taken last week on Sept 9 in Rockland and Lakeville, and Sept 10, 2024 in North Medford.

Table 1 Discussion:

The rate of starch conversion to sugars increased over the last week leading to current starch index values near 4. At the current rate of change, first pick fruit are expected to be optimally mature in a few days' time and should be monitored.

Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage for Honeycrisp are between 5.0 and 7.5. Starch index values are currently below but are approaching 5.0. When harvested early, the fruit are at greater risk of developing bitter pit in storage.

Where ReTain was used, starch index values are relatively lower near 2-3.
Please note that the DA meter values suggest that fruit are optimally mature right now BUT... we suspect a misalignment this year in using the predictive DA meter tool. The average DA value is currently reading 0.47 to 0.57 for tested fruit not treated with ReTain. The other maturity indices (starch, sugars etc.) show that maturity is not yet optimal. The DA meter was developed as a tool based on the relationship between chlorophyll degradation and the rate of change of maturity indices and in some years such as this with atypically warm weather the relationship may not align. I recommend relying on the starch-iodine test.
Soluble solids values in our region for Honeycrisp tend to be 11% at around optimum harvest maturity but again it depends on crop load. The soluble solids are currently not yet optimal.

More observations (data not shown):

Red blush colour is progressing well this year. Red colour on fruit not treated with ReTain is averaging around 60-70% in the outer canopy that would be targeted for a first pick, which is a 10-20% increase from last week.

See Figure 3 for an example of blush (top photos) and ground colour (bottom photos) progression over time on the indicated dates.
This year if colour is progressing better than it has in recent years, just be cautious about harvest maturity. In some cases high colour encourages harvest of immature fruit. Use all maturity indices in your decision whether to begin harvest. There are always tradeoffs though, including labour resources. Just be aware that early harvest of Honeycrisp can lead to more bitter pit in storage whereas late harvest beyond starch 7.5 results in more soft scald.

Fruit treated with ReTain generally have less colour (-10%) but are also correspondingly at an earlier stage of maturity.
If you feel that fruit size is ahead of normal at this point, consider more bins in your bin estimate. The fruit size in my samples averaged 215 g and growing at a rate of +11.5g/wk. The diameter was an average of 79 mm/3.11 inches and growing at a rate of +2 mm/+0.08 inches/wk. However, this information is highly dependent on the crop load in a particular block.
Side note: Some fruit have fewer or no seeds this year and it will be monitored. There is some speculation the lack of seeds may relate to cool April temperatures and possibly shed some light on the fruit drop this past season. It may be difficult to prove but is an interesting theory at this time.

Figure 3: Progression of red blush colour (top photos) and ground colour (bottom photos) change over time in 2024.

Table 2: Maturity indices for regular Honeycrisp fruit relative to the past 2-yr average (combined years 2022 and 2023) sampled on a similar calendar date.

Table 2 Discussion:

Starch index continues to be higher this year meaning that maturity is slightly ahead.
Soluble solids vary, likely related to crop load.
The DA meter values are lower this year meaning that the DA meter also predicts advanced maturity but note comments above about possible misalignment with actual fruit maturity.

About each maturity measurement:

Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block.

DA Meter - The delta absorbance (DA) value is related to the chlorophyll content of the peel. AAFC researchers in Kentville developed a protocol for Honeycrisp. Values above 0.60 are immature, values 0.6 to 0.36 are ideal for long term storage, and values below 0.35 are best for short term storage because they are more prone to storage disorders. Values shown above are the average of twenty fruit taken throughout a block, with readings taken on the transition area between the sun and shade exposed sides. DA values will be noticeably different between the most mature and least mature fruit on a tree.

New Resource - Video about Starch-Iodine Test

For those of you doing your own starch-iodine test, there is a short 3-minute video to guide you through the process.

This Orchard Outlook has been published with the input of the Orchard Outlook Committee including this week's contributors: Jeff Franklin, Joan Hebb, Bob Prange, Harrison Wright, Heather Rand, and Kari Brown.

Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist

Honeycrisp Fruit Maturity Report - Sept 10

Tuesday, September 10, 2024

This is the third maturity update for Honeycrisp using the example regions. Starch is beginning to convert to sugars and other maturity indices are discussed including new comments on fruit weight and diameter. There are also comparisons with last week and indices for this same time on the past two years. This report includes some information on using iodine solution.

Weather

Degree Day Accumulations

Total degree day accumulations are still slightly warmer than average and the trend has not changed significantly in recent weeks.

Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to September 9 for the past 17 seasons. Provided by Jeff Franklin (AAFC).

Approximately 4% more plant development heat units compared to the 5-year average, and 5% more compared to the 10-year average.
Approximately 5% more plant development heat units compared to 2023, and equal with 2022.
Approximately 5% more insect development heat units compared to the 5-year average, and 6% more compared to the 10-year average.

Mean Temperatures and Precipitation

Table 1 shows monthly temperature and precipitation totals for the growing season in comparison to the 25-year averages. The accumulation of heat over the last month of August was near-average. Jeff Franklin shares that, "The mean daily temperature for August was 20.0 °C compared to the 10-year and 25-year means of 20.1 °C and 19.9 °C respectively."

Apart from a few large precipitation events, we have not been receiving very much rain. Jeff Franklin summarizes that, "Precipitation total for August was 30.1mm compared to the 10-year and 25-year means of 101.2 mm and 91.6 mm."

Table 1. Mean monthly temperatures and precipitation totals for the current year compared with the 25-year averages. Provided by Jeff Franklin (AAFC).

Honeycrisp Fruit Maturity Report

Table 2: Maturity indices for regular Honeycrisp fruit sampled in the current year on Sept 9, 2024 in Rockland and Lakeville, and Sept 10, 2024 in North Medford. Values are compared with the samples taken last week on September 3, 2024.

Table 2 Discussion:

The starch has begun to convert to sugars so the starch index is higher than the base level of 1.0. Local research by John Delong et al. 2013 showed that optimal values of the starch index for long-term storage for Honeycrisp are between 5.0 and 7.5. Starch index values are currently below 5.0. When harvested early, the fruit are at greater risk of developing bitter pit in storage.
The average DA value is currently 0.72-0.75 for tested fruit not treated with ReTain. The DA value may come within the acceptable range within a week or a week and a half (Sept 20)(at an average rate of loss of 0.1 units per week). However, note that starch index is lagging behind and that the DA meter may be misaligned in this atypically warm year. I will update again next week.
Soluble solids values in our region for Honeycrisp tend to be 11% at around optimum harvest maturity but again it depends on crop load.

More observations (data not shown):

There is 4-14% more red colour at this time than at this same time the last 2 harvest seasons.
Red colour is averaging around 50% in the outer canopy that would be targeted for a first pick (fruit not treated with ReTain).

This year if colour is progressing better than it has in recent years, just be cautious about harvest maturity. In some cases high colour encourages harvest of immature fruit. Use all maturity indices in your decision whether to begin harvest. There are always tradeoffs though, including labour resources. Just be aware that early harvest of Honeycrisp can lead to more bitter pit in storage whereas late harvest beyond DA 0.36 or starch 7.5 results in more soft scald.

Fruit treated with ReTain generally have less colour but are also correspondingly at an earlier stage of maturity.
Background green colour has become noticeably more yellow over the last week.
If you feel that fruit size is ahead of normal at this point, consider more bins in your bin estimate. The fruit size in my samples averaged 203 g and 77 mm (3 inches) in diameter however this information is highly dependent on the crop load in a particular block.

Table 3: Maturity indices for regular Honeycrisp fruit relative to the past 2-yr average (combined years 2022 and 2023) sampled on a similar calendar date.

Table 3 Discussion:

Starch index is higher this year meaning that maturity is slightly ahead.
Soluble solids vary, likely related to crop load.
The DA meter values are lower this year meaning that the DA meter also predicts advanced maturity.

About each maturity measurement:

Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block.

Using Iodine Solution for Maturity Testing

For those of you doing your own iodine testing please note:

Generic iodine chart created for McIntosh is used as guidance.
Consult your packinghouse for suggested starch index values used to determine the first acceptable harvest date of specific apple varieties.

Local research by John Delong et al. 2013 and 2016 showed that optimal values for long-term storage are as follows: Honeycrisp between index 5.0 and 7.5 and Ambrosia between index 2.8 and 5.0

The correct starch-iodine index numbers for the first acceptable harvest date will vary depending on region so be careful of numbers that you use from other regions. Typically more northern regions such as ours will have relatively higher starch index values than southern apple growing regions for the first acceptable harvest date because low temperatures preceding harvest favour the conversion of starch to sugar.
Charts for varieties are available online but please note that the generic chart is the industry standard. The variety-specific charts just tend to show the variety-specific pattern of starch staining better than the figures developed using McIntosh. Just be cautious of the index values they report for long-term storage.
If you signed up for an iodine solution kit from Perennia, you should have received an email stating that it is now available for pick up at the Perennia office at 28 Aberdeen Street in Kentville.

Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist

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