Tree Fruit Newsletter — July 26, 2024
In this newsletter:
- Maturity Report
- Still Time to Collect Leaf Samples
- Predicted McIntosh Harvest and ReTain Dates
- Summer Pruning Peaches
Ready to Pick This Week at Highmoor Farm
We began peach and plum harvest yesterday. Shiro will be ready to pick soon, but we don’t have that variety anymore, so check your orchards for signs of ripening. Most varieties of plum and peach will continue to ripen after they are harvested. To prevent excess softening, bruising and decay, they can be picked when still firm, but should have gone from green to yellow in the peel. Expect ripening two days later at room temperature. Cold storage of peaches and plums may be necessary if you have more than you can sell at a given time, but expect some wooliness and internal browning with cold storage longer than several days.
Plums: Early Golden
Peaches: Manon and Desiree
Crop load and orchard location will impact the timing of peach harvest. Trees with a light crop load will have an earlier ripening date than those with a heavy crop. Orchard location has affected ripening in a way that I do not yet understand, so check each orchard block.
Leaf Sample Time
There is still time to collect leaf samples for determining nutritional status and fertilizer needs. Instructions were sent with the last newsletter and the form for the Lab that should be completed for each sample. Soil samples can be done anytime the ground is not frozen. Samples can be sent to Highmoor Farm or directly to the UMaine Analytical Lab in Orono.
Predicted McIntosh Harvest Date
All three models, based on temperatures in the days following bloom, are predicting an early start to McIntosh harvest for long-term storage. Sept. 7 is the estimated start and Sept. 16 the estimated end of harvest for long-term storage. Fruit will be at a partial stage of ripeness that is necessary for storage durations longer than two or more months depending on use of 1-MCP or CA storage.
We don’t have a model for Honeycrisp yet, but the ripening of Honeycrisp is dependent of crop load in addition to temperatures after bloom. Blocks with a light crop load can be expected to ripen ahead of blocks with a heavy crop load.
Predicted Dates for ReTain
ReTain® (AVG) can slow ripening and delay fruit drop for a week or more when conditions are good. Good conditions include ample soil moisture, normal temperatures and healthy foliage that is free of disease and spider mites.
For orchard blocks where you want to delay the start of harvest, ReTain should be applied about four weeks ahead of anticipated ‘first pick’. This would be Aug. 11 for McIntosh at Highmoor Farm. A second application will be needed 7 to 14 days later if you need to prevent preharvest drop in the same block. Keep in mind that the preharvest interval is 7 days. It may also delay red color development. Two applications are allowed.
For blocks where you want to begin picking early, but also wish to continue picking the same block at a later time, apply ReTain two to three weeks ahead of anticipated first harvest. This would correspond with Aug. 18 to 25 for Macs at Highmoor Farm.
ReTain is very effective on Honeycrisp and Gala, so less than the full rate is suggested with these varieties. Harvista is another effective stop drop material with specialized instructions. Contact your supplier.
For more info on ReTain, NAA and Harvista, visit the Fruit Management Guide website: Harvest management and preharvest fruit drop | New England Tree Fruit Management Guide
ReTain is also labeled for use on pears.
Summer Pruning Peaches
Summer pruning is generally to be avoided if possible. Leave it for trees that have little or no fruit, or trees with excessive shoot growth in the top of the tree. If you can’t see through the canopy, you have excessive shoot growth. I haven’t seen this in any of my orchard visits this summer.
By removing a few shoots from the upper canopy, more light will reach the lower shoots. Hopefully, they will grow stronger buds and will survive the winter. Other than this reason, summer pruning of peach trees has little benefit.
Renae Moran
University of Maine Cooperative Extension: Tree Fruits
PO Box 179
Monmouth, ME 04259
(207) 933-2100
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