Tree Fruit Newsletter — August 30, 2024
Maturity Report
Peaches
Peaches we are picking now: Coralstar and PF17
Coralstar is the better of the two varieties we picked this week. We have it in two different orchards where it ripens a week apart, so we will still be picking it next week. Veteran, PF23 and Blushingstar should be ready soon. We also have Messina, Glowingstar, Autumnstar and Tiana for mid to late season varieties.
Coralstar is ripening ahead of schedule because our trees have a very light crop load.
Apples
Zestar! and Paulared were harvested today at Highmoor Farm. Zestar! tasted good but is getting soft. It’s a summer apple that should be sold as soon as possible since its storage life is limited. Ripening is earlier than last year in Zestar! and Paulared.
McIntosh is showing an increase in starch breakdown, but it does not taste or look ready to pick for storage yet. There is still time apply Retain to extend the harvest window, but keep in mind the 7-day preharvest interval.
Honeycrisp does not show signs of ripening yet.
| Variety | Starch Index on Aug. 26 | Starch Index on Aug. 30 |
|---|---|---|
| Zestar! | 3.4 | 4.8 |
| McIntosh | 2.4 | 3.1 |
| Honeycrisp | 1.0 | 1.2 |
The following is a rough guide to what the starch index numbers mean for apple ripening:
1 – 2 indicates lack of starch breakdown and generally unripe.
3 – 4 indicates some sweetness developing and generally partially ripe.
5 – 6 indicates good flavor and ready for general harvest.
7 – 8 indicates fully ripe.
Starch index is measured on a scale of 1 to 8 and is an indicator of fruit ripening. However, it can be influenced by variety, weather and crop load. Starch breakdown begins in the core and progresses to the outer flesh as fruit ripen, and this can be seen with an iodine stain.
Renae Moran
University of Maine Cooperative Extension: Tree Fruits
PO Box 179
Monmouth, ME 04259
(207) 933-2100
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