Register here for one or both meetings, Registration Link

PLANNING FOR ORCHARD SUCCESS: PEST, POLLINATOR, AND CROP MANAGEMENT DECISION MAKING

Star Grazer Farm (Liberty Orchard)

2481 West St, Brookfield, VT 05036

Thursday May 7, 4:00 -6:30

and

Mad Tom Orchard

2615 Mad Tom Road, East Dorset VT 05253

Friday May 8, 4:00-6:30

Join the Vermont Tree Fruit Growers Association and the University of Vermont Extension at two hands-on field meetings at two of Vermont’s many beautiful apple orchards. We will learn about each farm, farm funding opportunities, see and discuss sprayer equipment, farm approaches to PYO, and discuss pest and pollinator management at each farm.

Star Grazer Farm (Liberty Orchard): This orchard transitioned to new ownership about 5 years ago. We’ll learn about the farm’s participation in recent on-farm bee pollinator research and see and talk about two types of orchard sprayers.

Mad Tom Orchard: This farmer led meeting will spotlight how orchard crops, management, weather station and spray equipment, markets, and customer relations have evolved in 85+ years of business.

Pesticide applicator credits available at each meeting location: 1 credit for categories 1A, 1, 2, 3, 4, 5, 6.  Certified Crop Adviser Credits pending.

FINAL2026-planning-for-orchard-success (002).pdf

With spring here, I recorded and posted a quick video in the UVM vineyard today, which you can see here: 4/28/2026 Vineyard walk. -TB

Buds are swelling in Vermont vineyards. At the UVM Horticulture Research and Education Center in South Burlington, yesterday, bud stages sorted into two general categories. Most ‘Minnesota’ cultivars (Marquette, Brianna, Itasca, Frontenac) are at the ‘wool’ bud stage; and most of the newer Plocher cultivars (also from Minnesota- Petite Pearl, Crimson Pearl, Verona) are a little behind at the bud swell stage. I’d expect bud break very soon, which brings up concerns for frost damage, what with it being April 28 and all. I made some comments on frost in a post from a few years ago that I will repeat again:

“There has been some recent discussion among growers about frost control measures after the cold snap that affected some vineyards. Questions about irrigating for frost control came up, and I’ll give my take on the subject: it is rarely worth it. Unless the irrigation system is carefully designed specifically for frost control (i.e. capable of outputting sufficient water to provide protection to the whole canopy), is run during the entire freezing event, and conditions such as low dew point or wind do prevent effective heat release from forming ice, then the significant effort likely won’t pay off and may cause even more damage than doing nothing at all. Frost fans are more commonly used in larger production regions, but they are very expensive and require their own specific conditions to be effective. I’ll echo comments made by others on the matter: the best frost control is good site selection, followed by good vine management. Row covers may be effective in mitigating frost conditions, but have their own infrastructure needs particularly a wire suspended above the canopy at 7-8 feet on which to hang the cover, and significant labor to apply and remove. I do not have experience to suggest a fabric type that would work best.”

Let’s keep our fingers crossed for a bit while we ride this out. The forecast looks mostly good for the foreseeable future.

Flea beetles are the main insect of concern at this point, and really only when bud swell through 1” shoot growth is slowed and the buds remain at this susceptible state for more than a week or so. It’s a good idea to keep an eye on buds and consider treating if more than 2% of buds are damaged. Remember, buds are no longer susceptible after 1” shoot growth, so if you make it past that stage, then don’t worry about them. This is really only a problem in years with a cool, drawn-out spring, and even then, the damage is rarely of economic significance. Clearing brush piles from around vineyard edges can help to reduce this pest.

The window to treat vines with liquid lime sulfur (LLS) for phpompsis and other disease management is closing as vine growth increases, do not consider applying high doses of that material to vines with green tissue showing. I described the use of LLS in my April 3, 2017 message.

Now that buds are swelling, I’d avoid use of systemic herbicides in vineyards unless you have a really good shield system to avoid contact with green tissue. This is a good time to burn down weeds, though, and an application of glufosinate can be effective now. Adding a premergent material like Chateau can extend weed control for a longer period. On the other hand, I find that in-row vegetation can help with excess soil moisture and vine vigor, as long as it is managed. I’m not promoting just letting the weeds go in a planting, and groundcover should be mowed and kept out of the canopy during the growing season.

__

Terence Bradshaw (he/him)
Associate Professor, Specialty Crops

Chair, Dept of Agriculture, Landscape, and Environment
(formerly Plant and Soil Science)
College of Agriculture and Life Sciences

University of Vermont
117/210 – Jeffords Hall | 63 Carrigan Dr
Burlington, VT 05405

(802) 922-2591 | tbradsha
https://go.uvm.edu/alebradshaw

UVM Commercial Horticulture | UVM Fruit Blog
Horticulture Research and Education Center
Message me on Teams

UVM’s Our Common Ground Values:
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UVM is subject to the Vermont Public Records Act and communications to and from this email address, including attachments, are subject to disclosure unless exempted under the Act or otherwise applicable law.

Here’s a quick note with rain expected in the next few days. -TB

With the dry weather that we’ve been experiencing the last week or so, we have had an extended time without apple scab infection periods. However, there has been significant development of ascospore maturity so the next substantial wetting event, which should occur during the extended rainy periods expected starting Wednesday and lasting through the weekend potentially, should result in a substantial and significant disease event. Everyone should have a good font contact fungicide in place going into the wedding. And should consider adding single site products either going into the period or applied during breaks in the rain to help with kickback in the case of imperfect coverage. On a brighter note, even as bloom appears to be off by at least a week or more, the NEWA models do not indicate a substantial increase in bacteria populations and with the onset of cool weather we do not anticipate any immediate concern about fire blight.

Insect pest monitoring should commence any time now in Vermont orchards. This year we are trialing the farmable app to help in collecting monitoring data and other information that may be useful in farm management. We discussed this program in my April 1 bulletin, and a recording of the onboarding meeting may be viewed here. I recorded a video today outlining how to log a set trap in the app so that growers may use it this season (sorry, it’s a little choppy). You can expect more discussion around the app as the season continues.

The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.

Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this message if it is in conflict with the label.

As we wrap up what could be a substantially damaging week for Vermont Apple Growers, I am heartened to have heard very little about damage from Monday night’s frost event. (Please report any damage in your orchard here). That doesn’t mean that there isn’t damage out there— we have heard reports of substantial damage just to the south of us where buds were a couple bud stages more advanced than in many Vermont orchards. At the UVM Horticulture Research and Education Center orchards, I assessed some buds on McIntosh, which was at green tip, and Zestar, which was more advanced at the early tight cluster bud stage. Our weather station recorded a low of 24° that night, and I expect that in some areas of the Orchard, especially near the ground, we had temperatures as low as possibly 22°. No Macintosh buds showed damage, however, about 10% of Zestar buds had damage on the king bloom in the cluster. All lateral blossom tissues were intact. This suggests that, at least at our orchard, the damage was minimal and can be managed through normal crop management and thinning procedures. It is best to assess your own orchard carefully before we get into thinning season.

I had a good IPM moment last Saturday when I went into the farm to give a lesson to an undergraduate pesticide applicator training course on sprayer operation and calibration. Since I was going in for a morning class anyway, I had planned to put on our green tip fungicide as I had recalled that there was to be rain in the forecast. When I got to the farm around 4 AM I was preparing my spray records and double checked NEWA. Following the scab model, I saw no risk for apple scab infection in the next 3 to 5 days, so I put the sprayer away and took a nap before class. I have been following NEWA every day, as we all should be at this time of year, and still have not seen substantial risk for apple scalp infection, so we have not sprayed the orchard since our copper spray on April 13. This does potentially leave the orchard in a vulnerable situation if a substantial scab event occurs, as we do not have any fungicide material built up on the trees so we will need to be ready to apply fungicide when the next infection period appears to be upon us, as we are approaching the advanced phase of ascospore maturity.

That doesn’t mean that it’s not still spraying season. This is the time to get in row weeds under control, so herbicide applications would be prudent. This is also an excellent time to apply oil to trees that are no further along than tight cluster bud stage. Oil should be applied at a 2.5% rate to trees that are at silver tip, 2% if trees are no further than green tip or early half inch green, and you could apply at a 1% rate to trees that are at the tight cluster bud stage. I would not apply oil to trees that are past the tight cluster blood stage, for fear of phytotoxicity. When applying oil, the percent rate is just that – 2% oil means 2 gallons of horticultural spray oil in 100 gallons of water. Water should be applied at a dilute rate so as to thoroughly wet the trees, this typically means around 100 gallons per acre. This is also a good time to apply pre-bloom foliar nutrients, such as zinc, nitrogen, and boron.

We will soon be setting insect monitoring traps in the orchards (pdf monitoring guide). The first traps that are set are for tarnished plant bug, and those could be set anytime now (video here). However, tarnished plant bug is not a substantial pest for most retail facing orchards. The damage from TPB is solely cosmetic, and it rarely reaches the level that affects perishable or marketable yield for pick your own or farm market-oriented orchard. The next traps that will be set are the same white sticky card traps used for TPB, these are set for European apple sawfly at the early pink bud stage. Traps should be placed at head height, at least three per orchard block, and monitored through bloom. EAS is both cosmetic and can be a substantial yield-reducing pest if in high enough population. I still typically do not recommend pre-bloom insecticide for most orchards, but orchards that have a history of European apple sawfly or in years where bloom is protracted, which prevents the application of a petal fall spray for several weeks, may call for treatment before bloom.

The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.

Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this message if it is in conflict with the label.

I don’t need to tell anyone that it was cold last night—I am seeing 26°, 22°, 20°F from NEWA stations and hearing reports from growers of even colder temperatures down into the teens. That’s not unheard of for mid-April, but depending on the bud stage of your trees, that’s enough to cause substantial damage to the 2026 crop. At the UVM Hort Farm, buds I checked around 1:00 PM yesterday were at solid Half-Inch Green bud stage, which the chart indicates that we would start to see damage at 23° and see 90% crop loss at 15°(our station recorded a low of 24°). I wasn’t able to get to the farm today, but will be doing a close check of the buds tomorrow.

Before making any changes to management, it is best to carefully assess the potential damage in your orchard. Sadly, I only need to go back to my May 2023 bulletins to offer a protocol to follow:

1. Unless you had multiple thermometers in multiple locations and heights in your orchard, you don’t really know the temperatures that any particular tree saw. There has been a lot of extrapolating from neighbor’s stations which can be helpful, but not to the degree of accuracy that would tell you the critical difference between 30° and 28° (or 25° and 22°).
2. Buds don’t read critical temperature charts– there are a number of factors that can affect bud hardiness, including cultivar, age, water or nutrient stress, etc. But we can assume that temperatures at or below 28° will start to show some real damage.
3. At this time, the most important thing to do is to assess your damage visually. This is really easy to do as damaged buds will show by now. I sent this link [on 5/18/2023] that will be helpful to review again. Basically, pinch the ovule at the base of the bud with your fingernail or a razor blade so you cut it at the equator. The interior should be completely green with no browning or worse, blackening. This can be seen without intense magnification but growers my age or older ought to have your readers with you. I also looked at buds today with someone who is color blind and realized that that condition makes it had to see the damage, so if you are, have someone else do the assessment.
4. Think about your strategy based on your freeze condition. Inland, and assuming your orchard saw 25° or colder? Go to your best spots- at the top of the hill, healthiest trees, buds collected head height- if you see extensive damage there, you can assume that the lower spots of the orchard are as bad or worse. In the Champlain Valley, your weather station said 29, 30°? Go to the low spots and assess, if you don’t see extensive damage then your better-sited trees are probably okay. Do a thorough assessment and write it down, especially of you will be applying for a crop insurance payment. I would start with 50 buds collected methodically and randomly from the canopy for each block and variety. If you have more than 50% damage, look more.
5. If you do have extensive damage and you have crop insurance, contact your agent ASAP. Even if you think you don’t have damage, keep an eye out in the coming weeks. Weakened buds can abscise later, or fruit may develop frost rings that make them unsaleable as fresh fruit.

I’ll end my quoted message there, as the rest included information on how to manage an orchard with little to no crop. I hope things aren’t that bad.

Damage may be reported at: https://go.uvm.edu/vttreefruitfreezedamage. I will use any aggregated reports to help develop management recommendations and to advocate for the industry as appropriate.

Good luck out there. And please let me know what things are looking like.

Best, Terry

The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.

Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this message if it is in conflict with the label.

Passing on this announcement for a webinar to be held today at 1:00 PM. While we are a bit further behind in Vermont than in many areas of New York, this material will be relevant to all growers in our region. I’ll be looking at buds in the next couple of days to assess potential cold damage from this morning’s cold temperatures, stay tuned.-TB

Zoom link:
https://cornell.zoom.us/j/99214892237?pwd=ulz4MrjKN6iBha5cwPPHI8dMcBOZKR.1

Agenda

1:00 PM – Welcome and Intros (Craig Kahlke, CCE-LOF)
1:05 – Early Crop Load Management Overview with Dr. Terence Robinson (Cornell AgriTech)
1:25 – Spring frost risk and mitigation with Dr. Jason Londo (Cornell AgriTech)
1:40 – Disease management with Dr. Kerik Cox (Cornell AgriTech)
1:55 – Disease management with Dr. Scott Cosseboom (Cornell Hudson Valley Research Lab)
2:05 – Insect management with Dr. Monique Rivera (Cornell AgriTech)
2:20 – Insect management with Dr. Andres Delgado (Cornell Hudson Valley Research Lab)
2:30 – Final questions and wrap up

The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.

Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this message if it is in conflict with the label.

I’ve received more than one inquiry about what one can do now to help alleviate potential frost damage hat may occur in the next week or two. The specific question has come up about the application of kelp extract pre-bloom to provide some level of frost protection. I must confess that I am quite skeptical such claims. I did my Master’s work studying kelp applications in an organic orchard and two of the three study years saw frost, and we saw no effect of the kelp treatments. While there are a number of non-replicated reports on the subject, a quick review of the peer-reviewed literature (there’s not much out there) indicates the same—no effect observed in most cases. There was one trial on pears completed in Macedonia that saw a slight increase in fruit set on trees that received a kelp extract treatment after frost, but a larger beneficial effect was seen on trees treated with gibberellins as you would have in Promalin.

One practice however for which there is ample evidence of providing trees with a general increase in vigor and ability to set fruit (notwithstanding a frost) is preharvest foliar fertilization. Now (half-inch green through pink bud stage) is a good time to think about applying a foliar nutrient tonic to help developing buds as bloom approaches. A combination of nitrogen, boron, and zinc is recommended and will help improve fruit set.

The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.

Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this message if it is in conflict with the label.

Passing this information on from Valent representative Jim Wargo. Keep in mind, the successful use of PGRs to offset frost damage is dependent on many factors, but ultimately hinges on sending a hormonal signal to receptive ovaries at the base of flower blossoms. Therefore application would be made later when trees are in early bloom. This gives time to assess any damage that may occur in the cold snap expected to come this Monday, April 20. =-TB

Managing Early-Season Frost Damage with Promalin® PGR

Freezing or near freezing temperatures are predicted for many parts of the northeast and mid Atlantic overnight on Monday April 20th. Depending on your location, apples may be in tight cluster or full bloom at that time. While apples are more cold-tolerant at the tight cluster to early pink stages than when fully open, temperatures of 27°F–28°F can still cause significant reproductive injury. Promalin Plant Growth Regulator can effectively rescue fruit set after such events, provided it is applied according to the tree’s natural phenology rather than immediately following the frost if trees are not yet in bloom.

Assessing Damage and Timing

Before treating, it is essential to determine if the injury threshold necessitates a rescue application. Remember, typically only one fruit per spur is needed for a full crop.

Some injury can act as a natural thinning event. Avoid overreacting to minor damage.

• Physical Inspection: Dissect flowers (opened or unopened) to inspect the reproductive parts. Brown discoloration indicates a dead pistil (the female organ), which prevents natural pollination and fertilization
• Limitation: If the vegetative receptacle tissue at the base of the flower is damaged or frozen, Promalin will be ineffective
• Patience is Key: Do not spray during the tight cluster or early pink stages. If trees are at full pink, wait until the first few king flowers open

The Science of Hormone Replacement

Promalin functions similarly to "hormone replacement therapy".

1. Natural Process: Normally, fertilized ovules develop into seeds that produce cytokinins and gibberellins. These signals tell the tree to nourish the fruit and it will then develop normally.
2. The Problem: If fertilization fails due to frost damage or poor pollination conditions (low bee activity) then no signals are sent, and the tree typically sheds the sterile flowers.
3. The Solution: Promalin provides these missing hormonal signals to sterile flowers. This allows the fruit to develop to a normal size, though it will have a low seed count or be entirely seedless.

Warm weather has substantially advanced bud stages on apples this week. In most of the production regions of the state, orchards are rapidly advancing through green tip and approaching or are at half-inch green. If you have any more than one “mouse ear” leaf showing from the developing buds, you should put the copper back on the shelf rather than risk fruit russeting.

The extended rains this week have led to an apple scab infection period across the state where there is susceptible tissue showing. Ascospore maturity is expected to pick up rapidly through the weekend which places us firmly in the primary scab season for most of the orchards in the state Orchards should be protected with a contact fungicide (e.g., mancozeb, captan, copper if still at silver tip or early green tip) before wetting events. For orchards with substantial tissue open that may have had poor or no fungicide coverage during these extended wetting periods, consider adding a single site material with some kickback potential in your next spray, especially if you had a history of scab last year. FRAC group 7 or 9 fungicides may be good options for this spray, and be sure to rotate the FRAC classes in your spray program as we move through the season. However, given the relatively low amount of tissue out there and fairly low ascospore maturity I do not suggest using kick-back materials except orchards in the warmest parts of the state.

We are expecting this showery weather through the weekend so I recommend getting coverage on orchards any time there is a break in the wind. We are expecting cooler weather next week so bud stages should slow down. I won’t say the f-word, but we should be keeping an eye on forecasts and keep in mind critical temperatures for fruit bud damage. Growers may consider a Promalin application to improve fruit set in cold-damaged trees, some details on that strategy are included in this bulletin from Amaya Atucha at University of Wisconsin. The window to treat is short, so a call to your chemical supply shop may be in order to prepare if needed.

Now is a good time to think about spring herbicides.

__

Terence Bradshaw (he/him)
Associate Professor, Specialty Crops

Chair, Dept of Agriculture, Landscape, and Environment
(formerly Plant and Soil Science)
College of Agriculture and Life Sciences

University of Vermont
117/210 – Jeffords Hall | 63 Carrigan Dr
Burlington, VT 05405

(802) 922-2591 | tbradsha
https://go.uvm.edu/alebradshaw

UVM Commercial Horticulture | UVM Fruit Blog
Horticulture Research and Education Center
Message me on Teams

UVM’s Our Common Ground Values:
Respect | Integrity | Innovation | Openness | Justice | Responsibility

UVM is subject to the Vermont Public Records Act and communications to and from this email address, including attachments, are subject to disclosure unless exempted under the Act or otherwise applicable law.

Introduction to FieldWatch Registries & DriftWatch Webinar
April 21, 2026 noon-1pm
Virtual via Zoom

Review of a new platform to strengthen communication, promote cooperation, and connect crop producers, beekeepers, and pesticide applicators.

Registration is FREE! Please pre-register at: https://go.uvm.edu/fieldwatch26

This program will provide pesticide recertification credits: 1.0 Vermont credit each (categories 1A,2,3A,3B,6,7B,10 & Private 1,2,3,4,5,6). In order to receive credits, you must be certified in one or more of the listed categories for the selected webinar and you must log in individually, with your Pesticide Applicator ID Number (entered at registration) by 11:50am. You will also have to stay logged in for the duration of the webinar and answer the poll questions that come up during and at the end of the webinar. If you are watching with someone else and both want credit, you will need to each have a device logged in and answer the poll questions separately.

Visit sarah.kingsley.

Sponsored by UVM Extension Pesticide Safety Education Program, Vermont Bee Lab, and Vermont Agency of Agriculture, Food & Markets
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status. Any reference to commercial products, trade names, or brand names is for information only, and no endorsement or approval is intended.

PSEP_FieldWatch26.pdf