Tree Fruit Newsletter — August 4, 2023
Fireblight
This disease is still showing up in apple orchards and is likely to continue spreading because of the frequent rainfall.
Anticipating Harvest
Orchard blocks with a light crop can be expected to ripen early compared to blocks of the same variety with a normal or heavy crop load. Take this into consideration in planning harvest for pick-your-own and other markets.
To delay harvest for apple picking in late September or October, a ‘stop drop’ can be applied. 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. I am not sure how frost damage will affect ReTain® this year. NAA (Fruitone, Fruit-Fix, PoMaxa) is another ‘stop drop’ that is less effective than ReTain® when used by itself. When applied in combination with ReTain®, it prevents fruit drop for a longer period than when either is used alone.
McIntosh is known for preharvest fruit drop that begins in late September or early October. Honeycrisp typically drops a few fruits at the start of harvest and then less after that, unless high temperatures and drought occur. 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 with specialized instructions.
For more info on ReTain®, NAA and Harvista, visit the Fruit Management Guide website:
Renae Moran
UMCE Tree Fruits
University of Maine Cooperative Extension
PO Box 179
Monmouth, ME 04259
(207) 933-2100
rmoran@maine.edu
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