Here’s a real quick update. Bud stage in warmest Vermont orchard sites is around half-inch green (HIG). At that point, copper should not be applied unless you know the crop is going to cider, as copper applied at any effective rate for this time of year will russet the fruit finish. Frost is expected, again, the next few nights. At HIG, buds are hardy to around 20°F. I see no immediate issues in that regard. But, frost means that oil and/or captan should not be used in the orchard, at least until late next week. Early season scab fungicides of choice should be mancozeb or scala/vanguard. Sulfur, of course, is the main material for use in organic orchards.
In the Champlain Valley, we’re still closer to green tip for now. That means that copper is still a viable material, but be sure to not apply it after the first two “mouse ear” leaves emerge from the bud. See the bud stage link (above) for a visual. Otherwise, default to those listed above.
Buds are around silver tip or even dormant in upland and inland sites. Hold tight there, although you could get a prophylactic copper on for fire blight, but that won’t help much against scab.
BUT, this doesn’t suggest that anyone needs to spray. Modeled ascospore development is around 1-7%, more in southern areas. Potential for rain is pretty solid today and fairly spotty until midweek. You need rain and extended wetting to cause infection. Here’s my take: orchard at HIG or later should maintain coverage, especially if you have an orchard that takes substantial time to spray. Time it as close to rain as possible; if you were uncovered going into today’s rain, cover as soon as this rain is done with a protectant + Vangard or Scala for some kickback. If you were covered or are in one of the lower risk sites (decent scab control last year, green tip or earlier bud stage), hold off until we get a better idea of the chance for rain later in the week. Of course, use NEWA to keep an eye on scab development in your area.
Insect notes: if tarnished plant bug is a concern in your orchard (less so in pick your own than wholesale orchards), then get traps up soon. We use white sticky traps from Gemplers or Great Lakes IPM. Set three per block, knee-high, on a lower scaffold out in the drive row. Check weekly, giving enough time to apply prebloom insecticide if needed. Trap thresholds are listed in our monitoring guide located here. Print that out and out it on your wall in the shop.
If you’ve had mite or scale problems, think about your options for managing them in the next few weeks. Oil is a great first line of defense, but if you have high populations, especially of scale, you may need to consider adding a stronger material prebloom. Esteem is most recommended for scale, applied around HIG to tight cluster. If mites have been a problem, there are a number of materials available for prebloom use, you’d best check the New England Tree Fruit Management Guide for recommendations.
Be safe out there.
Terry
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