University of Vermont

It is time to be thinking about applying ReTain to apples in Vermont orchards. This plant growth regulator slow ethylene production, thereby delaying ripening, reducing fruit drop, and allowing the grower (or customer) to harvest firmware, fresher fruit. Ione important consideration this year is that ReTain does not work as well on water stressed trees, so if you have the capacity, irrigate before applying or apply after a rain. In all reality, it’s time to get this on for our more important cultivars (McIntosh, Honeycrisp, Gala) so I wouldn’t wait. ReTain should be applied with an organosilicone wetting agent and under slow drying conditions. For more details, see Valent’s recommendations, including variety-specific protocols, here.

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 am passing this guidance on to apple growers regarding the legality of using acetamiprid and other insecticides in orchards when blooming weeds are present. As we are in apple maggot management season now, it is important to use materials effectively and safely, and many of us are using Assail to manage that pest. A recent news story contained an error at the end that stated that use of all neonicotinoid insecticides in the presence of any blooming plants is illegal. The Vermont Agency of Agriculture Pesticide Program is reaching out with this clarification.

While this guidance is very much appreciated, we must all remember to do our best and apply pesticides according to Best Management Practices. -TB

The [news story] states that applying a neonicotinoid insecticide if there are any flowering plants in the vicinity would be illegal. That is not accurate. The accurate statement would be that, as of July 1, 2025, applications of neonicotinoids to flowering crops is prohibited. Here is the pertinent language from Act 182 as enacted:

Sec. 4.

6 V.S.A. § 1105c is added to read:

§ 1105c. NEONICOTINOID PESTICIDES; PROHIBITED USES

(a) The following uses of neonicotinoid pesticides are prohibited:

(1) the outdoor application of neonicotinoid pesticides to any crop during bloom;

The language very specifically applies to flowering crops. In addition to the language added to the pesticide law (Chapter 87) the Vermont Rule for the Control of Pesticides (CVR 20-031-12) includes protections for bees in Section 5.04.

5.04 Protection of Bees

(a) No person shall apply a pesticide to a flowering crop, including alfalfa, apple, blueberry, clover, pumpkin, raspberry, squash, or trefoil without prior notification of at least 48 hours to an apiculturist who has an established apiary on the premises.

(b) A person hiring a commercial applicator for an application under Section 5.04(a) shall notify, or cause to be notified, the apiculturist at least 48 hours prior to the application.

(c) A person applying a pesticide that is highly toxic to bees shall:

(1) apply the pesticide during periods and conditions of least exposure, such as early morning or late evening; and when winds are less than nine mph; and

(2) include a 50-foot buffer from pollinator foraging sites, such as natural and semi-natural areas or intentional pollinator plantings or a 20-foot-wide non-pollinator-attractive vegetative barrier higher than the spray release height with an established 60% plant density.

(d) A person shall avoid the application of a fungicide or soil fumigant to pollinator-attractive plants when in bloom.

I have highlighted subsection (c). This section applies if the product being applied is classified by EPA as highly toxic to bees. Pesticides that are in this class will have a pollinator advisory statement on the label similar to the one reproduced below, as well as specific use directions that prohibit application to a crop while bees are foraging. These prohibitions are consistent with the requirements of rule 5.04 (c).

When considered in totality – the language added to Chapter 87, the language in rule 5.04 (c), and the label language for pesticides highly toxic to bees – it is not illegal to make an application to a crop when there are flowering plants in the vicinity of a crop to which application is otherwise allowed by these provisions.

It is good practice to minimize exposure to native pollinators through management of flowering weeds and plants that may be planted deliberately in the orchard , such as clover and legumes, through timely mowing or timing applications to early morning or late evening. In addition, good practice and label directions for use require minimization of drift onto non-target areas, such as where flowering weeds may occur. As we have discussed, UVM has developed recommendations for these practices, and it would be appropriate to remind growers of those recommendations given the attention to this issue.

I should also note that acetamiprid, which is commonly used in orchards for post bloom application, is not characterized as a pesticide highly toxic to bees and does not have the pollinator protection language on the label required for those products.

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.

One of our growers recently asked me to check on the rules for making and labeling unpasteurized cider in Vermont, and with the harvest and market season soon upon us, I figured others may have the same question. Cider processing is regulated by the Vermont Agency of Health, so I reached out to them to confirm their guidance on this. There is no concise webpage for this from the state, but we agreed that this guidance from Ohio is correct and applicable to Vermont producers: Apple Cider and Juice | Ohio Department of Agriculture.

Summary:

• Cider is considered a high risk food which may contain potentially dangerous organisms, chemicals, or physical contaminants that may harm consumers.
• Cider sold through any third party must comply with the Federal Juice Rule and be produced using Hazard Analysis at Critical Control Points (HACCP) processes and must undergo a treatment step (pasteurization, UV) that results in a 5-log reduction in harmful bacteria.
• All cider should be processed following the Health Regulations for Food Service Establishments (Robert.Manfredi

  -TB

  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.

Grapes are at or near veraison in Vermont vineyards, which signals the start of fruit ripening. This is an important time of year for a few activities. First, bird damage can be expected to begin and increase as fruit ripen. Birds will harvest your berries just a day or two before you’re ready to, so if you don’t have damage yet, don’t think you’re out of the woods. Netting is the best method of protection. Auditory scare calls, propane cannons, and inflatable ‘used car lot’ balloons are sometimes used as well, but their effectiveness is questionable and their annoyance factor significant. Dr. Alan Eaton from the University of New Hampshire wrote a good guide on prevention of bird damage in fruit plantings, available at: https://extension.unh.edu/resources/files/Resource001797_Rep2514.pdf.

Now is the time for plant tissue testing as well. Petiole samples may be collected at bloom or veraison, and comparisons between years or blocks should be based on the same time of collection. Samples should be collected separately for each cultivar or block. In each sample, a random collection of 75-100 petioles should be collected from throughout the planting. Petioles should be collected from the most recent fully expanded leaf on the shoot, not across from the fruit cluster as is collected for a bloom sample. Just remove the whole leaf and snip the petiole (the leaf ‘stem’ off with your pruners. Gently wash each sample in water with a drop of dish detergent, then rinse fully and place in an open-top paper bag to dry. The best analytical lab for grape petiole analysis that will provide recommendation for next year’s nutrient inputs is Dairy One, which is associated with the Cornell Nutrient Analysis Laboratory . Video about petiole sampling: https://www.youtube.com/watch?v=8EHbojLfXek

Disease management: as fruit ripen, they will become more susceptible to the various bunch rots, including botrytis, ripe rot, and sour rot, and canopies can be affected by late-season downy and powdery mildew. Good cultural management for all of these includes keeping the canopy open, ensuring that clusters can ‘see the sun’ by shoot combing / thinning, removal of leaves, and pruning of laterals. There may be a few sprays warranted at this time, with some big caveats. Copper, sulfur, and captan should be avoided as we approach harvest, as they can either inhibit fermentation of contribute to off-flavors in the finished wine. Consider preharvest intervals, too. Visible downy mildew can be managed through leaf removal, or application of one of the various Phosphorous acid products (e.g., Rampart, Fosphite). Some other materials that have efficacy against DM may be found in the New England Small Fruit guide. Be sure to rotate fungicide resistance classes (FRAC codes). There may be a bit of powdery mildew in the vineyard as well, that can typically be managed with a thorough application of stylet oil, applied as soon as it is observed in the vineyard. Botrytis can be specifically managed with fungicides, but it will be difficult to get into any closed clusters like Petite Pearl, and that disease is best managed during the immediate postbloom window. Remember that not all varieties are equally susceptible to disease, and loose-clustered varieties tend to have less issues with botrytis overall. There is some concern regarding spotted wing drosophila (SWD) and its potential to damage ripening fruit, which leads to sour rot infections. This invasive pest has been seen in high numbers in the region this year, but that does not suggest cause for alarm among the vineyard community. SWD have lower preference for grapes than for other soft fruit, and winegrapes that will be processed immediately after harvest are less prone to damage from secondary diseases. Still. Good vineyard sanitation is key in managing this pest. Any damaged clusters with cracked fruit should be removed from the vineyard in the weeks between veraison and ripening, as these attract SWD and other rot-bearing fruit flies. SWD have a preference for protected, shady areas in the canopy, so, again, keeping clusters exposed to sun is a helpful practice. While there are many insecticides labeled for control of SWD, I do not recommend their use in vineyards in any but the most specific cases.

Start making plans for harvest and crush now. This may be a good time to thin out any lagging ‘green’ clusters that developed from secondary buds and are lagging in ripeness. Remember, you’re looking for crop uniformity. You can estimate yield by counting clusters on a few representative vines and multiplying by the typical cluster weight for your vineyard. If this is unknown, use 0.25 pounds (113 grams) per cluster, which is the average we have recorded at the UVM vineyard for Minnesota cultivars from 2010-2020. Your formula should look like this:

Estimated tons/acre = average # clusters/vine * 0.25 lbs/cluster * # vines per acre /2000 (pounds per ton)

For the UVM vineyard, where we have 726 vines per acre [43560 sq feet/acre / (6 feet between vines * 10 feet between rows)] = 726, the crop estimate for 50 clusters per vine is:

4 tons/acre = 50 * 0.25 * 726 / 2000

Three to four tons per acre is a good crop for mature, healthy vines for most cold climate cultivars; some vigorous vines in good health may support higher crop yield but I wouldn’t push mush more than 5.5 tons per acre lest you compromise ripening. If you have too many clusters, thin out the smallest and greenest ones to get your target cluster number. This exercise will help you plan lugs, bins, and tank space, as well as allow you to communicate that information to any wineries you plan to sell to.

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.

Foliar nutrient analysis – It is the time in the growing season to collect leaf samples for analysis. Samples are usually collected between July 15 – Aug. 15. The UVM Agriculture and Environmental Testing Lab can provide analysis, but at this time their output does not generate fertility recommendations. The following are potential options of labs for analysis. It is recommended that you contact the lab for instructions and costs before samples are sent. Plus, it is important to confirm that they will send recommendations along with the analysis.

1. University of Maine Analytical Lab: http://anlab.umesci.maine.edu/. Direct link to the leaf sampling form here.
2. Agro One: https://dairyone.com/services/forage-laboratory-services/plant-tissue-analysis/

Instructions on collecting leaf samples can be found here.

Wrapping up spraying – Primary insects of concern are apple maggot and codling moth. Both should be managed in high-pressure orchards. AM can often be managed with a single insecticide application based on monitoring with red sticky traps. The threshold is two flies per non-baited trap, or five flies per trap if apple volatile baits are used. Codling moth are between flights in most orchards, so management is advised later this month if this pest is a problem for you. Insecticide options are listed in the New England Tree Fruit Management Guide. Dr. Arthur Agnello discussed these summer insect pests in more detail in the July 7, 2014 issue of Scaffolds .

Summer diseases – It is important to maintain fungicide coverage to protect against sooty blotch, fly speck, and summer fruit rots. Materials should be applied after every 200 accumulated hours of leaf wetness or 2 inches of rainfall, whichever occurs first.

We ate our first peach yesterday, harvest will be here any day now.

TB

__

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/pssbradshaw

UVM Commercial Horticulture | UVM Fruit Blog
Horticulture Research and Education Center
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Climate Adaptation Field Walk at Scott Farm Orchard: Dummerston, VT on August 19

WHEN: August 19, 3:30 pm – 5:30 pm
WHERE: Scott Farm Orchard, 707 Kipling Rd, Dummerston, VT 05301

Adapting to climate change looks different on every farm. This field walk will explore the range of climate risks impacting Scott Farm’s orchards and diversified production, from changing rainfall patterns to extreme temperature fluctuations. Scott Farm Orchard farm manager Simon Renault and orchardist Erin Robinson will share insights into the diverse strategies they’re using to adapt to these challenges, with a focus on business planning and preventative management. ​

Click here to learn more and register!

This event is sponsored by American Farmland Trust’s Planning for Adaptation & Resilience to Climate Change Program in collaboration with NOFA-VT. Thank you to our funders: NRCS-Vermont and the Vermont Agency of Agriculture, Farms and Markets.

“This message and its contents are confidential. If you received this message in error, do not use or rely upon it. Instead, please inform the sender and then delete it. Opinions in this email may only be those of the author and do not necessarily represent those of American Farmland Trust. The contents of this email do not constitute a binding offer or acceptance by American Farmland Trust unless so set forth in a separate document.”

The Vermont Agency of Agriculture, Food and Markets is in the process of adopting a rule required by the General Assembly that establishes Best Management Practices for the use of neonicotinoid treated article seeds and neonicotinoid pesticides. The Draft rule language was developed over the last year and a half through a public process using recommendations from the Agricultural Innovation Board (AIB).

The Draft rule language, as presented to the House and Senate agriculture committees, and approved for publication by the Interagency Committee on Administrative Rules (ICAR), is attached.

The Agency will hold five public hearings to get public comments on the Draft rule. Information on these is presented below.

Date	Time	Location	Virtual Option
8/12/2025	5pm-7pm	Virtual Only	TEAMS Link Meeting ID: 253 157 432 933 1 Passcode: UM3EW6nx
8/14/2025	5pm-7pm	Bixby Memorial Free Library (2 Main St, Vergennes, VT 05491)	TEAMS Link Meeting ID: 253 157 432 933 1 Passcode: UM3EW6nx
8/20/2025	5pm-7pm	Poulin Grain (3916 US-5, Derby, VT 05829)	TEAMS Link Meeting ID: 299 306 540 079 1 Passcode: d5m5mZ9V
8/27/2025	430-630 pm	St. Albans Free Library (1 Maiden Ln, St Albans City, 05471)	TEAMS Link Meeting ID: 239 248 720 071 2 Passcode: h34Bb7yt
9/3/2025	5pm-7pm	Brooks Memorial Library (224 Main St, Brattleboro, 05301)	TEAMS Link Meeting ID: 258 187 034 640 8 Passcode: VR3yx2gY

Please consider attending, as the state is looking for broad perspectives on this proposed rule.

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.

Best Management Practices for the Use of Neonicotinoid Treated Article Seeds and Neonicotinoid Pesticides (ICAR)(4.30.25).pdf

The time has come to hang apple maggot fly (AMF) traps in Vermont orchards. These are some of the easiest pests to manage using an IPM strategy, so there’s really no excuse. The idea is to assess the population in the orchard before applying prophylactic sprays. By using red sticky traps, you can time treatments for best effectiveness, and maybe even skip treatments if the populations are low enough. Traps are red plastic balls that you coat with Tanglefoot adhesive. Kits including traps and adhesive are available from Gemplers and Great Lakes IPM. We have some available from our program as well, if you want to swing by South Burlington. If you want to come by for traps, please email me and we’ll be sure to have some ready.

AMF traps should be hung at least four per 10-acre block, preferably at the orchard perimeter and especially near sources of the insect, like wild or unmanaged apples. (Video here: Vermont Apple IPM: Hanging apple maggot fly traps.) Placement in the tree should be about head-height, and surrounding foliage should be trimmed away- this trap is largely visual, and you should be able to see it from 10-20 yards away. The traps may be baited with an apple essence lure that improves their attractiveness dramatically. When using traps to monitor AMF populations to time sprays, unbaited traps that catch one fly per block (as an average of all the traps in the block) would warrant treatment; the lure makes them much more attractive such that you can wait until an average of five flies per trap are caught before treating. For most growers, the main insecticide used against AMF is Assail, Imidan also works but it has a long reentry interval and tends to leave visible residue on fruit. For organic growers, Surround works well, but its use in midsummer may increase European red mites, and it can be hard to remove at harvest; spinosad (Entrust) works pretty well too. First AMF treatment is still a few weeks off, most likely.

It is summer lepidoptera season, and monitoring and treatment should be on everyone’s minds, especially for codling moth (CM) and obliquebanded leafroller (OBLR). CM are active and eggs are likely still hatching across the state, so growers who have caught CM in their traps or who often have issues with this pest (that’s most everyone) should apply something effective against them at the appropriate time. Most orchards saw CM first trap captures in late May and peak at the beginning of June. Optimum spray timing for CM is 250 degree days (base 50°) after first catch with a follow up spray 10-14 days later. Very specific materials like insect growth regulators (Intrepid, Rimon) or granulosis virus (Madex, Cyd-X) can be used that are very safe to non-target insects. One or two applications of a material should suffice for first generation.

OBLR are just showing up in traps but generally at low levels compared to previous years, and treatment should be timed at 360 degree days (base 43°F) after first catch. There is a NEWA model for this pest, and a material like Bt (Dipel, etc.) is effective (but not against CM). Other good materials targeted at this lepidopteran pest include Intrepid, Rimon, Delegate, and Belt.

I have seen one pretty bad case of European red mites already, and hot, dry weather is also conducive to mite flare-ups. A weekly or, if the numbers indicate, bi-weekly scouting will help to indicate if there are high enough mite numbers to consider treatment. Information on monitoring: https://netreefruit.org/apples/insects/mites. Mites should be treated based on the following thresholds: in June, 1-2 mites per leaf; July, 5 mites per leaf; in August, trees are more tolerant of feeding so treatment should only be applied if there are over 7.5 mites per leaf.

Diseases: keep checking on your scab, if you have none (I mean none), then it’s okay to relax. That said, the summer diseases sooty blotch and flyspeck are of concern now, but they require 270 hours of leaf wetness for lesions to form, so fungicide coverage between that period should be maintained. I am also seeing more leaf spot diseases (here’s a great article on the different leaf spots you may encounter) this year that may warrant continued coverage to reduce potential defoliation and/or spread to fruit rots. Recommendations from our colleagues at Cornell suggest including a FRAC group 3, 7, or 11 fungicide with your captan cover to reduce incidence of these diseases. Keep in mind that one inch of rain washes off half of your coverage, after two inches, it’s gone.

It’s time to wrap up any ground-applied nitrogen fertilizers, but potassium and magnesium fertilizers can be applied any time in summer. It’s also a good idea to start your regular foliar calcium sprays, especially on bitter pit-prone cultivars like Honeycrisp and Cortland.

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 will be a fairly brief newsletter today as I am away all week at a conference in Chicago. Feel free to e-mail or text me if you have specific questions, I will keep up the best that I can. -TB

We are entering into what I consider early summer insect management season. The main insect of concern at this point is codling moth, although plum curculio may still be active in some orchards. Two times sprays against codling moth, pheromone baited wing traps would have been hung prior to bloom and the date of first sustained capture recorded. From that point degree days are calculated using a base of 50°F and hatching larvae are best treated when 220° days have accumulated. For the UV orchard where we had sustained moth capture on May 17th, that would put us at good timing to manage our first generation of codling moth this week. Our orchard has a relatively high population and this emergence is earlier than I have seen in other orchards in the region, so your site may be able to be treated next week in the Champlain Valley or even later in the cooler inland orchards. Cottonmouth should best be managed with a material that specifically has high efficacy against that particular pest. Some good options are presented in this table Apple Insecticide Efficacy : New England Tree Fruit Management Guide : UMass Amherst (best seen on a computer or tablet screen, it doesn’t render well on a smaller phone screen).

Even though primary apple scab season is done for virtually all orchards in the state, I still recommend applying at least 1/2 rate of captan as we continue to have wet weather and some are diseases and fruit rots can get out of control if not managed. This is also the time to be applying calcium in every spray, especially on Honeycrisp.

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 on from Bethany again. -TB

Hi there again folks,

I’m writing in to you on the eve of the most important disease prevention period of our grape systems! Over the past two weeks we have had several Phomopsis and black rot infection events according to our NEWA models. As we enter pre-bloom it is essential that we are using our most powerful disease prevention and suppression tools against black rot, Phomopsis, and maybe even powdery mildew in vineyards where this is a particular concern.

Part of why there have been so many infection events is because we are experiencing so much rain. Both Phomopsis and black rot infections are spread by rain splash and are encouraged by humid and warm temperatures over 60 degrees. While we can’t do much about the weather, other management strategies will include:

Cultural methods (EXTREEMELY important for organic growers)

• Making sure you’ve thinned shoots! By removing excess plant material you not only better balance the vine, but also allow for better spray penetration and airflow both now and into the summer months.
• Remove any woody material that has not flushed out by now. This material will act as a disease reservoir if not removed promptly. It is worth taking a walk through the vineyard to find what you may have missed

Chemical Methods

• Check available NEWA models to track possible infection periods. The model uses climatic data such as rainfall, temperature, and hours of leaf wetness to predict infection events. Be sure to enter the shoot stage and use the closest station to you for the most accurate predictions. Contact Terry if you are interested in hosting a station!
• Because pre- and post- bloom is THE MOST IMPORTANT infection window for diseases such as black rot and powdery mildew we should all be applying our best and most reliable materials. Recs from Terry: “Every vineyard should be covered with the full suite of disease management products this week. That means mancozeb or captan plus a DMI, SDHI, or strobilurin (group 3, 7, or 11, respectively) material for non-organic vineyards; and sulfur plus copper (watch for incompatibilities on certain varieties, page 9 here) on organic vineyards. This would also be a good time to add biologicals, since we’re at ‘all hands on deck’ right now. Some materials, like Lifegard and Howler, are systemic acquired resistance promoters and need to go on a few days prior to infection. Others, like Serenade and Double Nickel, are biological extracts but can be mixed with other materials. Either way, these applications should be made a before infection, so spraying in the next day or two is a good idea.”

That’s all for now- I myself have to prep for a spray tomorrow. I will be in touch soon to introduce our good friend Downy Mildew and talk about weed and canopy management!

Signing off,

Bethany Pelletier & UVM Fruit Lab

__

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/pssbradshaw

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.