Late summer, and harvest date window for apples

In the time since I last reached out, some orchards have been deluged with rain, others haver received welcome and needed moisture. As we approach harvest (I picked my first, just under-ripe Williams Pride apple today), it’s important to get our ducks in a row.

Spraying should be wrapping up soon. I hope growers have been using red sticky traps for apple maggot fly management. I have seen myself and heard others’ reports that AMF are on the low side this year. Don’t take my word for it- pay attention in your own orchard, as damage will only get worse as fruit start to ripen. It’s also a bit on the late side but still in the window to treat for second generation codling moth where you have that problem (again, your traps will tell you). I plan to treat our orchard on Monday with Assail to manage both of those pests.

Summer diseases may be more of an issue this year, especially where maintaining fungicide coverage has been difficult with all the rain. One last treatment with a DMI or strobilurin product should get you to harvest, especially if mixed with a little captan. Fire blight is still around, too. We are still seeing it in the UVM orchard, which I attribute to cutting it out during rainy July. Advancement does seem to be slowing, but a cut thorough cut-out before harvest will help to reduce the inoculum load in the trees next year.

Keep applying calcium, especially on Honeycrisp, Cortland, Northern Spy, and other large-fruited varieties.

There have been some questions about early maturity this season. I ran the Cornell Harvest Maturity Model for McIntosh using HREC data from South Burlington, and came up with a recommended last harvest date for CA storage McIntosh of September 11. This is indeed about a week early. The model is largely driven by heat units in the 30 days after bloom, as well as the actual bloom date. This spring was generally (but not always) warm, and bloom a bit early. However, take this model with a grain of salt. The nature of the model- predicting date for CA storage of McIntosh- dates back to a time when we were predominantly a a) McIntosh industry and b) wholesale / packing house industry. This means no disparagement to those who still operate on a wholesale production and sales model, but those of you who do should use more accurate starch index testing (details in the same link) to time harvest. Starch iodine solution is available here. Another important caveat is that this model, published in 1992, is based on a climate and growing conditions that we can no longer count on e.g., cool nights in September; moderate summer high temperatures; and larger, somewhat shaded semidwarf trees. So take that all with a grain of salt, but I’ll agree- from my observations, we’re running about a week early. I expect this will moderate as we approach fall, though.

Finally, we all ought to be prepared for another round of COVID affecting or operations. Things are moving fast- UVM just instituted a mask mandate for indoor spaces yesterday, and new restrictions may be coming down the pike. This isn’t our first round with this, and arguably many orchard did better as customers flocked to outdoor activities last fall. Let’s all be wary of new developments and use a little extra caution and common sense. I’ll pass on any further guidance I get from the state as it comes.

Take care,