After a long, drawn-out winter like those from the ‘good old days’, it’s hard to believe that spring often happens pretty quickly. By that I mean that we’ll shift from winter activities when the sleeping trees provide us plenty of time and bandwidth to tend to certain tasks, but when the buds open and green tissue starts showing, we need to shift and be ready for the growing season.
I predict that it is likely we’ll see some green tissue this week if we haven’t already in some of the warmer spots. That means that scab management should begin very shortly, with a copper application recommended on virtually all orchards between the green tip and no later than the 1/4” green tip bud stage. I would plan on applying copper to any orchard that had any amount of fire blight last year and which is showing green tissue or at least solid silver tip as soon as you have a suitable spray window. If possible, I would plan on applying copper to any orchard, period, that is between silver tip and half-inch green in the next 7-10 days. There is a pile of materials out there and for all intents and purposes for this delayed dormant spray any of them are effective as long as you are applying a good full rate of copper ions. The standard dry materials like Champ, C-O-C-S, Cuprofix, Kocide, etc. will give you the best bang for the buck here, and I would apply the full label rate for any of them and thoroughly spray the whole orchard. The only caveat I offer is if phenology advances rapidly before you can get out there and the trees are at 1/2” green tip, in that case, I would apply a low to middle rate. After 1/2” green tip, unless you don’t care about fruit finish (e.g., cider fruit), I would avoid copper.
This isn’t a bad time to get oil on, either, but the rate should be 2% by volume and coverage absolutely thorough to soak overwintering mite eggs, scale, and aphids. If time is of the essence, focus on copper first, especially in orchards south of the rain line that seemed to set up between Addison and Orange/Windsor counties last year which had a fair amount of scab going into the winter.
Speaking of which, there is still time to do some sanitation in the orchard by flail mowing leaves and fine brush, and/or applying a coarse urea spray (44 lb feed grade urea in 100 gal water applied per acre, directed at the leaf litter).to speed decomposition and reduce apple scab inoculum.
Keep an eye on NEWA regularly as we enter into the 2019 season. Up-to-date spray tables may be found in the New England Tree Fruit Management Guide available online at netreefruit.org and shortly in hard copy format.
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