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:
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

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