Apple pollinator workshop in Burlington May 10th, VT pesticide credits and CCA CEUs available

Greetings growers,

I hope this message finds you well. At UVM Extension we have been working on an upcoming in person apple grower workshop to be held in Burlington during the anticipated apple bloom period. It is the first of two on pollinators in fruit production.

Supporting and Monitoring Pollinators in Apples, 4:30-6:30pm, Wednesday May 10, UVM Horticulture Research and Education Center, Burlington VT

Supporting and Monitoring Pollinators in Blueberries, 5:00pm-7pm, Tuesday May 23, Cedar Circle Farm and Education Center, Thetford, VT

I have attached a flyer and the apple meeting agenda for more details. There will be 2 pesticide applicator credits and 1.5 CCA CEU available with meeting participation. Thanks so much for considering and hope to see you there.


Laura Johnson

University of Vermont, Extension Pollinator Support Specialist


327 US Route 302 Suite 1 Berlin, VT 05641

Cell: 802-291-2118


Apple meeting agenda for 5.10.2023 twilight meeting.pdf

Vermont Apple IPM- Tight Cluster

I am leaving for a research conference for the next week, so I am getting out a preemptive notice of things to watch for while I am away. So, while I am discussing disease management, remember to check NEWA to assess actual disease conditions before applying prophylactic sprays in your orchards.

Bud stages have moved pretty rapidly in the past ten days, and we are a good 7-10 days ahead of ‘normal’. In many years I start spraying the orchard on or around earth day. This year I started April 13, and put a second spray on this morning to buy some protection while I’m gone for a week. If you have the notion, you can report your bud stage dates at this link ( to help me keep an eye on things around the state.

Orchards are at or around the tight cluster bud stage in Champlain Valley of Vermont, which means that there is plenty of tissue out there for apple scab to infect, and the disease is in a critical management phase. Orchards should be covered with an effective contact fungicide (mancozeb, captan, sulfur if organic) going into any expected wetting periods. If coverage is questionable going into a wetting event, a postinfection material may be used- Vangard is effective prebloom and during relatively cool weather. There are several others, too- see the New England Tree Fruit Management Guide apple spray table for details. Note that these post-infection materials, including DMIs, SDHIs, Strobilurins, and Anilinopyrimidines, have high potential for the fungus developing resistance to them, so always mix with a protectant and rotate fungicide classes every application. Organic growers have fewer options for postinfection materials. I am not recommending liquid lime sulfur anymore, as it is just too caustic and dangerous to applicators, trees, and equipment. Some materials such as the peroxide (e.g., Oxidate) and bicarbonate (e.g. Armicarb) based fungicides have shown efficacy when applied during infection, as the spores are germinating on wet leaves, but are pretty limited in providing any real control after cuticle penetration has occurred. Bottom line: keep the orchard covered.

There is still time to apply oil to manage mites and scale. I am a proponent for putting oil on as late as possible, up to tight cluster or even pink. The rate should be adjusted down as buds open more: 2-3 gallons per 100 gallons water (straight % in tank, not adjusted for tree for volume or per acre) is good from dormant through green tip; 2 % GT-tight cluster; and 1% as you approach pink. Oil should be put on dilute- slow down and open up your nozzles if you can. For most orchards, 100 gallons of water per acre should be the minimum for applying oil. That means recalibrating your sprayer in many cases.

Trees are approaching their peak energy needs as bloom approaches. Now is a good time to get your first soil-applied nitrogen fertilizer down. In many cases, split applications are more useful than a single application, timed at tight cluster to pink and a second application at petal fall. Without a foliar analysis (which is always the gold standard for developing fertilizer recommendations), growers should err on applying a total of 30-40 pounds of actual nitrogen per acre whether in one or two applications. This is also a good time to apply the foliar tonic of urea (3#/100 gallons), boron (1# solubor or 0.1-0.2 lb actual B/100 gal) and zinc (many materials, use label rates). I wouldn’t mix this tonic with oil, do one and then the other in this next spray or two if needed.

VT Apple IPM: Green tip this week?

At this time of the year, we should always be keeping an eye on the weather in the week ahead, and the shift toward warmer temperatures this week suggests that we may be seeing the first signs of green tissue on trees in many sites in Vermont. Green tip indicates the beginning of the growing season, and is an important biofix for apple scab models. Keep checking your trees daily and note the date when 50% of buds on ‘McIntosh’ have opened enough to see green tissue from the side. That date should be used in NEWA to mark your biofix for apple scab ascospore maturity.

Potential for apple scab infection increases with temperatures as more ascospores mature to be released in rain events. In the early season. Not many spores are mature, and if you had good scab control last year, i.e., no visible lesions all season, then the small percentage of mature spores in a low inoculum situation may give you some early season breathing room. But if you did have a problem with scab last year, or a neighboring orchard harbors substantial inoculum, you should be ready early in the season to protect your trees. Copper is the standard, first spray of the year in virtually all orchard, as it helps to reduce fire blight inoculum and is a moderate fungicide against scab that can cover the first infection event for that disease.

But copper is a tricky material- it must be on the plant and not washed-off by the time fire blight cankers are oozing with the onset of warm weather, but if applied too late, copper ions on developing buds can cause fruit russeting. 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.

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 2023 season. Up-to-date spray tables may be found in the New England Tree Fruit Management Guide available online at and shortly in hard copy format.

April 1- not fooling anyone, spring is around the corner

I am writing a somewhat rare joint apple-grape bulletin today to start off the 2023 season. This year marks my 29th season growing apples in New England, and 18th (I think) growing grapes. That’s a long time to be at it, when just before that I was convinced that I left farming behind when I left the dairy farm and headed off to college. Such is the way things go. I hesitate, however, to continue to call myself a farmer, particularly as the letters after my name and number of words in my title grows. Suffice to say that, despite the changes in duty I’ve had over the years, I remain committed to Vermont specialty crop growers, and look forward to the season ahead. My former colleague and mentor Lorraine Berkett always said we needed to be ready for the growing season by April 1. Like many, I am not ready, but the season will come to us as it does, and I plan to use these notes to help us all get through it together.

This season I have an excellent team working with me on both crops that I have research and Extension responsibilities for. My two graduate students, Bethany Pelletier and Eli Wilson, will be helping me out both by conducting their own research and teaching activities and by helping to be eyes and ears on farm both with me and with undergraduate students we will host this summer. You can expect to see their bylines a bit as they share their experiences with the community. I also have a new operations manager at the farm, Brian Vaughan, who will help me out with spraying and other work at the UVM farm, once we get him set up with his applicator’s license.

Speaking of pesticide rules, the Vermont Pesticide Rules were updated for the first time in over 30 years this past winter and the new rules went into effect in February. Every grower should review the rules here. The changes are a bit too long to summarize here, but include standardization of classifications; new rules for applicators; new standards for recordkeeping; standards for protection to pollinators (or particular interest to fruit growers, more to come on this); and changes to transportation and storage requirements. A summary of the regulation changes may be found in the Spring 2023 Vermont Pesticide Applicator Report, starting on page 3. That report also includes a refresher on the updated Worker Protection Standards rules that you should refresh yourselves with before the growing season commences.

I will put in a separate and distinct comment here- I don’t care if your operation uses organic, non-organic, or other materials, becoming a licensed applicator ensures that you have been trained, maintain training, and are tested on your knowledge of safe use of agricultural chemicals. Everyone in our community should be trained, licensed, and hold ourselves to the highest standards to maintain environmental quality and ours’ and our workers’ and families’ safety as we protect our crops.

I’ll wrap up with a suggestion to get your ducks in a row for the season that will rapidly be here. Besides getting up-to-speed on regulations and requirements, we should be cleaning, testing, and calibrating our sprayers; checking and ordering inventory; finishing up pruning; performing orchard and vineyard sanitation by shredding leaf litter and brush; and getting set up with a weather station and monitoring program for your farm so that you can make informed and wise decisions rather than rely on gut instinct in the season ahead.

Here’s to a good spring and great growing season overall.