VT Apple IPM: Petal fall thinning meeting TODAY, 1PM

I want to get this one out quick:

(Cornell) Champlain Valley Virtual 10-12mm Thinning Meeting Today at 1PM
The Champlain Valley 10-12mm meeting will be held today from 1-2PM. At this meeting, Dr. Terence Robinson will discuss his thinning recommendations for the 10-12mm timing. To join, simply click on the link at 1PM.

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Meeting ID: 995 4427 4591

Passcode: 288556

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On that note, here’s my quick rundown of things to in the orchard:

  1. Manage plum curculio. This should be pest # 1 right now, and with hot, humid weather, its activity should be pretty high. PC is active from petal fall but especially at 8-12 mm fruit size, until 308 degree days (base 50°F) after petal fall. There is a model in NEWA, use it.
  2. Codling moth is pest #2. If you monitored CM in pheromone traps and recorded first date of capture, use that in the NEWA model, or hand calculate degree days (also base 50°F). Sprays should be timed at 150 DD for ovicidal materials (Rimon, Intrepid, Esteem) or 250-360 DD for most other materials. As usual, use the New England Tree Fruit Management Guide to help guide selection.
  3. Start adding calcium to sprays any time now, especially on Honeycrisp.
  4. While we’re talking nutrients, trees are in their main flush of growth, so any nitrogen fertilizers you’ll be applying should be going on now.
  5. Water! Things are really, really dry out there, and that’s not looking to change any time soon.
  6. Because of that, apple scab is on the back burner, mostly. When we get rain, scab will be an issue. When you next spray, make sure you’re staying covered.
  7. There are a lot of reports about powdery mildew showing in area, which does not require leaf wetness, only high humidity. For orchards with a history of PM and with susceptible cultivars (Cortland, Gala, Ginger Gold, Idared, Jonathan, Mutsu (Crispin), and Paulared), you may want to include a material with some efficacy against the disease. From the NETFMG: “The most common multi-site fungicides, captan and mancozeb, are ineffective against powdery mildew. DMI fungicides vary in effectiveness. Unfortunately, the DMIs most effective against powdery mildew, Rhyme, Rally, Rubigan and Procure, are least effective against scab, and vice-versa. QoI fungicides, Flint, Flint Extra and Sovran (and pre-mixes with Group 11 ingredients) have good efficacy against powdery mildew. SDHI fungicides, Aprovia, Fontelis and Sercadis (and pre-mixes with Group 7 ingredients) are somewhat less effective, but still provide good control. Low rates of sulfur are effective in low disease pressure environments, such as New England, but the risk of sulfur injury increases as temperatures go over 85°F. In organic production systems, sulfur applied at weekly intervals, and bicarbonate and peroxide-based fungicides applied on 3-5 days intervals are the best options. (TB note: in my 12+ years of growing apples organically using sulfur to manage scab, I never saw PM in orchards managed using that system.)
  8. Keep an eye out for fire blight infections. If you find any, cut them out as soon as you do. But, please send me an email, as my colleague Dr. Kerik Cox at Cornell is tracking Erwinia amlovera (the causal bacteria of the disease) strains in the northeast and testing for streptomycin resistance.

Okay, that’s all for now. Who knows a good rain dance??