June 18, 2017
I am doing some last minute preparations for my summer cold-climate viticulture course which starts this week (and still has a few slots if you’re interested), so this will be relatively brief. Codling moth (CM) should be tended to in most orchards in the warmer valleys this week if you have any question about them being a problem- and they are an increasing problem. candidates to use. Plum curculio and European apple sawfly should be all done doing their damage by now, so it’s just CM and some other leps that you’d be managing. This should be a great week to target first generation egg hatch, and CM-specific materials like granulosis virus (effective against CM only, with some efficacy against Oriental fruit month OFM), growth regulators (Intrepid, Esteem), and reduced-risk materials like Altacor and Assail would be good candidates at this time.
We are trapping all sorts of other moths, including lesser apple worm and OFM, which may be managed similar to CM, generally.
Apple maggot traps should be hung soon. These red sticky balls can be purchased from Great Lakes IPM or Gemplers. Buy the inexpensive ones and throw them out, we have spent countless hours over the years scrubbing the old wooden spheres in various solvents and the (literal) headache just isn’t worth it. Traps should be hung at least four per managed block, preferably at the corners of the orchard adjacent to woods or other overwintering areas. Organic growers with small plantings may ‘trap out’ by using a (much) larger number of traps as described here. Most growers find it easier to use the traps to monitor the flight of the flies and time a spray application, which may (hopefully) be timed to manage second generation codling moth as well later in July.
Diseases: this is the week to scout you orchard carefully for apple scab; if you have more than 1% of leaves affected, you’ll need to keep a protectant like Captan on until the terminal buds set and leaves become less susceptible. Fire blight is popping up, we are finding it in the usual trees at the UVM Hort Farm and cutting it out. Please let me know about anything bigger than a sporadic infection in the usual hot spots. Sooty blotch and flyspeck aren’t a problem right now. Frankly, unless you find scan, I’d put the fungicides away for now.
Water if you need to; apply calcium in most every spray and extra calcium in Honeycrisp. You can apply potassium-based fertilizers any time, that large crop this year will draw a lot out of the tree/soil. Of course your cation (calcium/potassium/magnesium) applications should be based on soil and, even better, foliar samples. Those will be ready to take in mid-July.
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