University of Vermont

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
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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

With the warm weather coming in, we expect most Vermont orchards to be at green tip in the next few days if they have not gotten there yet. This is an ideal time to think about beginning your pest management season by applying a whole orchard copper spray. Copper should be applied to apples before the quarter inch green tip bud stage to reduce the likelihood of fruit russeting. Copper is a relatively weak fungicide, but can provide enough protection for the first one or two apple scab infection periods when ascospore maturity may be relatively low. The primary purpose for copper at this time of the season is to reduce the load of bacteria which may spread fire blight. Copper needs to be on the surface of the plant when bacterial ooze starts to exude from the tree around bloom. The specific type of copper is of less importance than the total amount of elemental copper that is on the surface of the plant after application. We generally recommend any of the main forms of powdered coppers including copper sulfate, copper hydroxide, or copper octanoate applied at label rates.

If you choose to get a jump on insect and mite management, you could consider applying spray oil at this time also. However, spray oil may be more effective if applied a little later in the season—say, between half inch green and no later than tight cluster. If applied at this point a 2% by volume mixture of spray oil in water could be used. Oil sprays should go on either at full dilute or at most a 2X concentration, so I would recommend most orchards be treated with at least 100 gallons of water when making that application. This makes oil sprays slow going and so it may be best to wait until a long window of agreeable application weather is available.

Speaking of weather, it looks like the best window to apply copper or any other spray material in the next few days is Sunday morning 4/12, as we will be between wind events at that time.

Separate from spraying, good orchard IPM practices include cultural and biological controls as well. One important practice to consider at this point which can be done even while the wind is blowing is flail mowing brush and especially leaves to help aid with decomposition and to reorient leaves now that ascospores have developed. Over the winter, the apple fungus develops pseudothecia in which ascospores are formed which result in the primary inoculum for the disease season. Pseudothecia develop facing the sunlight, and so even if 1/2 of leaves are flipped over during a mowing operation, those ascospores within them will eject into the ground rather than into the canopy during wedding events. Therefore, a careful mowing of foliage can have a significant impact on the potential inoculum as we head into the primary disease management season.

As always, check the New England Tree Fruit Management Guide or the Cornell Tree Fruit Management Guide and always follow the label for your specific materials.

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.

This is a joint announcement from the UVM Fruit Program and the Vermont Tree Fruit Growers Association. We typically consider April 1 the ‘start’ of the apple growing season in Vermont, so here we are- trees still dormant, weather cold and damp, but green tip and the start of the 2026 crop right around the corner. We are partnering with VTFGA on our orchard monitoring program this year- they are sponsoring our collaboration with Farmable for collection of scouting data, we are providing traps to growers who agree to participate. Funds to provide traps are limited so we do ask limit this offer commercial growers (however you choose to define that). We’ll have regular trainings via email or online meeting to help implement scouting this year. Farms do not need to participate in the scouting program to receive our now roughly-weekly email bulletins, they will come through this list as usual. -Terry

Hi everyone,

We have been working to refine the 2026 UVM Fruit Program/VTFGA IPM Monitoring Program and seek to share some updates. This years efforts include launching a multi-year Program to support Vermont growers in tracking pest activity and sharing monitoring data with the UVM IPM Program. This information helps provide timely guidance on pest pressure and management decisions, strengthening and refining effective IPM practices across Vermont orchards.

Your participation is important. The more growers involved, the stronger our Vermont-specific data will be—supporting better recommendations, industry reporting, and research that directly benefits our state’s orchard industry.

We encourage all VTFGA members to please participate and help build a stronger, more informed pest management network for Vermont growers.

What’s new this year

We’ll be using the Farmable app to make it easier to record observations while you’re out in the orchard. You can log trap counts and notes directly into the app on your phone, rather than needing to go back and enter data later. The VTFGA will support a shared account that allows participating growers to easily share their scouting data to the UVM Fruit Program. UVM will use this data to provide membership timely guidance on pest pressure and management decisions as well as use the information for industry reporting and further Vermont orchard research.

This year will be a trial run as we explore how well the app works for growers. A free version of Farmable is available for mapping and note-taking (including trap counts). Growers will also have the option to upgrade to a Pro version at a discounted rate if they’re interested in additional features like calculating tank mixes, spray records, job creation and harvest tracking. Farmable Pro, a $399/ annual cost will be offered at $149 for VTFGA members for 2026.

If you’re interested in participating but are not comfortable using a phone-based app, please feel free to reach out—we’re happy to talk through other options to ensure your participation.

What’s expected

Growers who participate will:

· Set up and monitor provided traps throughout the season

· Conduct weekly scouting

· Share scouting observations with UVM (ideally through the Farmable app). ALL Farmable data is owned by the orchard. Orchards select what they share with UVM.

Farmable will provide how-to videos and technical support. The UVM IPM Monitoring Program will also be available for additional guidance and support.

Next steps

Please see the links the UVM Fruit Program/VTFGA IPM Monitoring Program interest form and Participation Agreement which outlines the program in more detail. If you would like to participate this season, please fill out both forms and return the Agreement by April 5th tovtappleinfo. With this information, we will coordinate to deliver traps to you and give you next steps in Farmable or otherwise to get you started.

https://go.uvm.edu/2026uvmapplescoutinterest

https://go.uvm.edu/2026uvmvtfgascoutagreement

Please do not hesitate to reach out with any questions. Thank you and here is to a great kick off to the 2026 growing season!

Best Regards,

Jess Yates and the VTFGA Board

Terry Bradshaw and the UVM Fruit Program

Julie Callahan from the UVM Vegetable and Berry Team reached out to offer this opportunity to advertise your farms on their website. -TB

VVBGA Pick Your Own website- Please create or update your listing!

Last year, 723 people visited the Vermont Vegetable and Berry Growers Association Pick Your Own website with almost 2,000 views of individual farm listings. Please help us build on that success by adding more tree fruit farms! It takes 5 minutes to create a listing you can update whenever you want. Customers can find your farm at vermontpickyourown.org using a map or list.

How to set up a VVBGA member account to create a listing
1) If you are not a VVBGA member, go to https://vvbga.org/user/register/farm and create an account.
2) Click on the “Complete Online Membership Form” button to complete membership. Since you won’t be using most of the membership features, you can choose the $0 payment option under membership fee.
3) Click “Pick-Your-Own-Listing” on the left-hand menu.
4) Click the orange “Add Your Listing” button.
5) When you click on each section of the listing, a drop down will appear to fill in the details of your farm’s PYO operation.
6) Hit the "Save” button at the bottom of the page after you complete your listing.

Prefer visual or video instructions? A visual guide to creating your listing is posted here. First 4 minutes is of this webinar an intro to the PYO site. The next 5 minutes describes how to create your listing.

Thanks to the 47 farms and orchards who created listings to market a wide variety of PYO crops- apples, berries, flowers, pumpkins and more! This website is owned by VVBGA, so you can share feedback on how to make it better.

Please reach out if you have questions or need help creating a listing. Julie Callahan, julie.callahan, 518-944-7149

Julie Callahan (she/her), Farmer Engagement Specialist

Julie.callahan 518-944-7149

UVM Extension Commercial Horticulture Team

Information on Funding Opportunities https://go.uvm.edu/vegfundinglist

Passing on this webinar to anyone interested. These are great webinars that many may find useful. -TB

Link: https://extension.psu.edu/advancements-in-grapevine-nutrition

Description: Advancements in Grapevine Nutrition

This session brings together four members of the USDA/SCRI Hi-Res Vineyard Nutrition Project to share concise research updates and practical deliverables that support balanced grapevine nutrition in commercial vineyards. Presenters will address practitioner perspectives on nutrient needs across regions, best timing and tissues for macro- and micronutrient sampling, new outcomes from fertilization studies, and the use of spatial technologies to guide variable rate applications. The program will conclude with an open discussion and question-and-answer period to encourage applied learning and grower‐focused dialogue.

The Eastern Viticulture and Enology Forum (EVEF) Webinar Series is a collaborative initiative of the Penn State Extension Grape and Wine Team and partnering viticulture and enology extension programs from U.S. land-grant institutions. You will have the opportunity to submit questions prior to the webinar using the link contained in your registration confirmation email.

Cain Hickey, PhD

Assistant Teaching Professor of Viticulture

Department of Plant Science

Penn State

318A Tyson Building

University Park, PA 16802

viticulture

814-440-5534 (mobile)

Penn State Extension Grape and Wine Production Website (extension.psu.edu/grapes-and-wine)

PSU Wine and Grape Team Facebook Page

https://extension.psu.edu/grape-and-enology-team-sign-up

https://extension.psu.edu/cultivars-in-the-commonwealth