VT Apple IPM: Pink, Bloom, Petal Fall edition

Here we are on May 11, with bud stages all over the place. I’m seeing trees near me in upland/inland central Vermont at tight cluster bud stage; hearing reports from Bennington of trees at pink; and have trees at our orchard in full bloom and starting to lose a few petals. This is always a tricky time for management, and growers may need to be ready to apply different treatments to different parts of the farm. Here’s my quick rundown:

Insects: Generally, there are too many flowers out there- both apple blossoms and dandelions on the orchard floor to be spraying without impacting pollinators. In few cases is a pink insecticide spray needed, in my opinion, especially in retail-oriented orchards. However, the drawn-out prebloom period may increase the time that sensitive tissue is out there to be fed on by numerous pests. Keep an eye on traps, and if you haven’t hung any yet, at least get your codling moth traps up to determine your biofix date. Point being: be ready to treat after bloom (and mow those groundcover flowers first), but don’t get knee-jerk. Wait and see, for now.

Diseases: Fire blight risk is really low, as temperatures have been too cool anywhere for bacterial populations to build up. Keep an eye on NEWA if you have later blooming cultivars and the weather starts to warm up. Apple scab, on the other hand, is primed with very high ascospore maturity. Any decent wetting event is likely to cause an infection, so keep covered with a protectant fungicide and use a single-site SDHI, Strobilurin, DMI, or combination material if you have any questions about coverage going into a wetting period. This week is a bit tricky to time the sprays, as there has been and continues to be a low top moderate chance of rain most days this week, but not really enough to know for sure if a spray would be wasted.

Thinning: It’s looking like a heavy bloom year, so aggressive thinning is probably going to be called for. Plan on, at a minimum, a petal fall application, followed up by another at 7-14 mm fruit size. Successful thinning depends on many factors, I’ll highlight them more in light of upcoming weather in a few days. Be sure to adjust materials based on the NEWA Apple Carbohydrate Deficit Model. I’m also including Dr. Duane Greene’s advice from a recent UMASS Healthy Fruit Newsletter here.

“Bloom and Petal Fall Thinning

Duane Greene

Flower development has been erratic and proceeding in fits and spurts. However, it does appear that development in many orchards is approaching or will be at full bloom this week. The bloom and petal fall stages are excellent times to start your chemical thinning.

Bloom and Petal Fall

Bloom is a time when orchardists frequently do not choose to thin. The bloom period has not yet occurred so there is uncertainty about how favorable it will be for bees to fly. Also, the potential for frost still exists. However, it should be noted that the sooner you can start the thinning process, the better chance you have of influencing and encouraging return bloom. There are several options available to use at bloom.

Petal fall is a thinner time of application that most orchardists choose. The pollination period is known and there is a reduced chance of frost. If a bloom thinning spray was not applied a petal fall application of a thinner becomes very important.

With one exception (Carbaryl) the same hormone thinners can be used at either bloom or petal fall. When selecting a thinner(s) it should be emphasized that thinners are not as potent when used at bloom as when they are applied at the traditional 7-14 mm stage. A rough rule-of-thumb is that thinners applied at bloom and petal fall are about 50% less effective at thinning as they are if they were applied at the 7-14 mm stage.

Naphthaleneacetic Acid (NAA)

NAA has been used by growers for over 75 years. There is some comfort in using a compound that has passed the test of time. I routinely suggest application of NAA at 10 to 12 ppm. I have never over-thinned a tree using these rates. Lower rates will be less effective. NAA at 10 to 12 ppm could be applied to a broad spectrum of cultivars.

Naphthaleneacetamide (Amid-Thin)

This is a thinner that has garnered increased interest from growers recently. Amid-Thin is a weaker thinner than NAA and it rarely, if ever, over-thins. It has a reputation for being a reasonably consistent thinner. The label allows application of up to 8 oz/100 gal. I do not recommend using a rate any lower than 8 oz/100 gal. (Ed. note: Amid-Thin W is not currently registered in Rhode Island.)

Ethephon

Ethephon may be used as an early thinner. The recommended rate is 300 ppm or 1 pt/100 gal. Some have applied it at a rate as high as 400 ppm with good results. It may not be as consistent as other thinners but it remains a viable option. Since it produces ethylene it may also be useful to enhance return bloom.

Carbaryl

Historically, this has been the most popular thinner in New England. Unfortunately, it is very toxic to bees so it can not be used until the bees are removed from the orchard at petal fall.* Carbaryl is unusual as a thinner in that its effectiveness is concentration independent. It is routinely used at 1 pt to 1 qt/100 gal. Carbaryl is an excellent choice to combine with either NAA or Amid-Thin at petal fall to enhance thinning activity. I like the addition of carbarly with Amid-Thin to enhance the thinning activity of Amid-Thin.

Petal fall is a somewhat nebulous term. I consider it to be a period of time between the time petals fall from the flowers and when the receptacle starts to grow. Early in this period the receptacle is not growing, or growing very slowly, so there is little carbohydrate demand exerted by the fruit. Consequently, I generally do not pay much attention to the carbohydrate model during this period of time. However, when fruit grow to 5-6 mm then the carbohydrate model plays an important role in making thinning decisions.

Bloom and petal fall thinner applications are an important component in a comprehensive thinning program. This opportunity to help regulate crop load should not be missed. The real danger in bloom and petal fall thinning is not over-thinning but not thinning enough!”

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.

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.

UVM Extension helps individuals and communities put research-based knowledge to work. 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.

OnLine Pesticide Applicator Recertification Courses – NE Reciprocity

Passing these training opportunities on from our colleagues at University of New Hampshire. If you need pesticide credits, or just want to pick up some tips on application or safety, check them out. -TB

Good morning,

My name is Rachel Maccini, I am the Pesticide Safety Education Program, Coordinator with UNH Extension. We have created and have received approval from our State Lead Agency (NH Department of Agriculture, Markets & Food, Division of Pesticide Control) for recertification credits on 11 online Pesticide Safety courses. The courses are focused on important pesticide related topics. The courses are available to all certified pesticide applicators throughout New England and have been approved by Pennsylvania’s State Lead Agency as well. Because New England has reciprocity with each NE state, if a state lead agency has approved an event, workshop, course and/or meeting it will be accepted in other NE states, we are hopeful you will offer these opportunities to your clientele. The courses are located on the eXtension website and can be accessed 24 hours a day. Each course is designed to be interactive, keeping the student engaged while involving them in the learning. The courses cost between $20-$40 per course (depending on the topic). Once the course is complete the student will take an assessment in which they will need to pass before a certificate of completion is awarded. If you need additional information and would like to discuss this in more depth please let me know.

https://extension.unh.edu/blog/recertification-credits-online

Topics available to pesticide applicators:

Calculations for Mixing the Right amount of Pesticides Category Right of Way

Calculations for Mixing the Right amount of Pesticides Category Structural Pest Control

Calculations for Mixing the Right amount of Pesticides Category Turf

Welcome to Integrated Pest Management (IPM) Recertification Course

New Hampshire’s Personal Protective Equipment (PPE) Recertification Course

New Hampshire’s Pesticide Hazards and First Aid first aid route of entry Recertification Course

New Hampshire’s Label and Labeling Recertification Course

New Hampshire’s Storage and Disposal Recertification Course

New Hampshire’s Backpack Sprayer – Part One Recertification Course

New Hampshire’s Backpack Sprayer – Part Two Recertification Course

Worker Protection Standard (WPS)

Rachel Maccini MS Ed.

Pesticide Safety Education Program Manager

PHONE:

MOBILE:

EMAIL:

WEB:

ADDRESS

603-351-3831

603-921-1034

Rachel.maccini

https://extension.unh.edu

329 Mast Road

Suite 115

Goffstown, NH 03045

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.

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.

UVM Extension helps individuals and communities put research-based knowledge to work. 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.

Agritourism Operation Checklists and Self-Assessment — Tuesday at 7pm

Passing this on from another colleague at UVM Extension. -TB

Subject: Agritourism Operation Checklists and Self-Assessment — Tuesday at 7pm

Agritourism Operation Checklists and Self-Assessment
Tuesday, May 11, 7-8pm Eastern Time

No charge but you must register in advance.

Register HERE

Are you ready to welcome visitors to your farm during the evolving pandemic? Join growers, extension personnel, and ag service providers in the Northeast for presentations and discussions about using self-assessment checklists to evaluate management considerations for on-farm direct marketing and agritourism operations. Developed by Rutgers Cooperative Extension, these checklists are relevant throughout the Northeast.

Featuring Brian Schilling, Michelle Infante-Casella, William Bamka, Stephen Komar, Meredith Melendez, and Rick VanVranken from Rutgers Cooperative Extension.

This session is part of a series that will cover several topics for farms open to visitors through the evolving COVID-19 pandemic.

To request a disability-related accommodation to participate in this program, please contact Christi Sherlock at 802-476-2003 or Christi.Sherlock so we may assist you.

Interested in having a safety expert visit your farm? A team of ag service providers in the Northeast is providing personalized safety assessments that will take place either virtually or on your farm. Sign up HERE.

Feel free to reach out with questions anytime.

Hope to see you on Tuesday!

Lisa

This material is based upon work supported by USDA/NIFA under Award Number 2018-70027-28588.

Statewide (NY) Virtual Bloom Thinning Meeting via Zoom next Monday May 3rd, 4-5pm

Forwarding from our Cornell colleagues across the lake. -TB

Dr. Terence Robinson, Dan Olmstead, and others will continue to present the detailed and practical implications for bloom thinning with and without the use of the Pollen Tube Growth Model in apples. There will be ample time for questions and discussion. At meeting time, please click the following link, there is no need to preregister: https://cornell.zoom.us/j/95697849291?pwd=K0JJc0ZLb2JoaVg5VXR4YTloK2N5QT09

Meeting ID: 956 9784 9291

Passcode: 061465

One tap mobile +16468769923,,95697849291# US (New York) 16465189805,,95697849291# US +(New York)

Dial by your location +1 646 876 9923 US (New York), +1 646 518 9805 US (New York)

Please see the introduction to bloom thinning by Dr. Robinson and much more (Nutrition by Dr. Cheng, Apogee at pink on Honeycrisp for BP suppression by Dan Donahue, Fire Blight Management by Dr. Cox, and Insect Management at Pink from Dr. Jaime Pinero (UMass) from our Statewide Virtual Pink Meeting that was held on April 27 here: htps://www.youtube.com/watch?v=fnF6y_fCdqw

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.

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.

UVM Extension helps individuals and communities put research-based knowledge to work. 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.

Vaccinations in the workplace & PYO Prep

Passing this on from the VT AAgency of Agriculture, Food & Markets. -TB

Good morning Terry,

Please share the upcoming COVID-19 related sessions with fruit growers as you see fit.

Thanks,

Ollie

Ollie Cultrara (they/them)

Produce Program Outreach & Education Coordinator

Vermont Agency of Agriculture, Food & Markets | agriculture.vermont.gov

Cell: (802) 461-5128 | 94 Harvest Lane, Williston, VT 05495

COVID-19 Updates and Resources

Find us on social media: | Subscribe to Agriview

Sign up for updates on marketing opportunities, events, and grants

Two upcoming virtual sessions address COVID-19 considerations on farms (details below):

  • Vaccinations in the Workplace – Thursday 4/29, 2-3 pm
  • Getting Ready for Pick-Your-Own: Do’s and Don’ts for the Upcoming Season – Tuesday 5/4, 4-5 pm

Vaccination in the Workplace Forum

Thursday, April 29, 2-3 pm

Free and you must register in advance.

Is your farm considering asking employees to get the vaccine? The VT Manufacturing Extension Center is offering a free forum for employers to learn more about the human resources and legal issues around requiring or encouraging workers to get the COVID-19 vaccine. Panelists will discuss workplace vaccination policy considerations, requesting proof of COVID-19 vaccination, and best practices for communicating with employees about these policies, among other topics.

Getting Ready for Pick-Your-Own — Do’s and Don’ts for the Upcoming Season

Tuesday, May 4, 4-5pm

Free and you must register in advance.

Do you open your farm to visitors/customers? Join growers and ag service providers from the Northeast for an interactive discussion about what is working and what is not as we prepare to open our farms to visitors for the upcoming pick-your-own season. The berries are ripening and the Covid-19 pandemic is evolving – what does that mean for PYO visitor management this season? What did you do last year that you’ll continue and what will be different this season?

Featuring: Lisa Chase from University of Vermont Extension, Deb Colitas from Valley Fruits & Veggies in the Lehigh Valley of PA, Claudia Schmidt from Penn State Extension, and YOU! Come ready to share your PYO questions and experiences managing visitors.

This is the first agritourism zoom café in a series that will cover several topics for farms open to visitors through the evolving COVID-19 pandemic. To request a disability-related accommodation to participate in this program, please contact Christi Sherlock at 802-476-2003 or Christi.Sherlock so we may assist you.

Interested in having a safety expert visit your farm? A team of ag service providers in the Northeast is providing personalized safety assessments that will take place either virtually or on your farm (not just for PYO, this is for any type of farm open to visitors). Sign up HERE.

This material is based upon work supported by USDA/NIFA under Award Number 2018-70027-28588.

VT Apple IPM: First big apple scab event expected

I may be a little late in getting this out, but everyone in the state should be prepared for the expected scab infection event that will be occurring Wednesday – Friday of this week. The NEWA model for some sites is still reading low for ascospore maturity- they are working on that in the back end. For most orchard in the Champlain Valley, we should have about 20% of ascospores mature- plenty to protect against. Be prepared with a preventative contact fungicide (mancozeb / captan, sulfur if organic) and consider adding a single-site product like Vangard or one of the DMI materials if you can’t get on before the rains start or you want some powdery mildew protection.

Insects are quiet so far, but I know some growers like to put a pink insecticide in as a matter of course. I’m not in that camp, and most sites are still a week out from pink anyway, but if you do use a prebloom insecticide, please stay away from neonicotinoids (IRAC group 4, e.g. Assail, Actara, Transform WG) that could express themselves in pollen and nectar and pose a unique danger to pollinators. Better yet, use white traps and only apply a prebloom insecticide against European apple safely and/or, in rare cases, tarnished plant bug, if populations are above threshold.

Make sure you order you codling moth traps and get them up in the orchard by bloom.

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.

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.

UVM Extension helps individuals and communities put research-based knowledge to work. 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.

VT Grape IPM: Buds swelling, flea beetles, lime sulfur, weed management

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 27 and all. I made some comments on frost in a post from a few years ago that I will repreat 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.

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.

VT Apple IPM: Cold weather worries, scab model out of whack

I’ve been getting a lot of questions- interestingly, none from growers- about the effect of this weather on fruit buds in the state. My answer has been consistent: I’m not concerned about what we’ve seen so far, but I am concerned about what we may see ahead. Dr. Rob Crassweller at Penn State wrote a good summary earlier this month on Frost, Critical Temperatures, and Frost Protection. The general gist is that, once apple buds are at tight cluster bud stage, we should be concerned when temps go below 28°F, and expect near-complete crop loss below 21. That’s a gross generalization, as duration of cold, bud nutrient status, relative humidity, and other factors do come into play. Checking around the state, I see that where buds are likely most advanced at tight cluster or even very early pink (Chittenden, SW Windham, Bennington counties), it looks like the low dipped around 27-28 this morning. That could be enough to do a touch of damage, but likely not take out a whole crop. Where buds were more advanced (and therefore less cold-hardy), or in low-lying parts of the orchard, there could be more damage. The best thing to do is wait a few days, then assess some flower buds visually for signs of damage. Thanks fully, it looks like last night was the coldest we’re expecting for as far out as I trust the forecast, but there’s a lot of potential cold weather season ahead.

Dr. Crassweller does discuss some methods for protecting from frost damage in his article, Unfortunately, none of the methods is easy or can be found in a jug. To date, there remains no good research that has shown consistently (or even any) improved frost protection from something you can buy in a jug. The #1, 2, and 3 best methods for preventing frost damage are selecting a good site. Other practices that promote general tree health and good groundcover management are the next ones to consider. Active frost protection methods include various ways to either heat or move the air. The former includes heaters, and I know of no orchard that has them in sufficient quantity. Some growers have been known or light round hay / straw bales on fire in the orchard, but that has never been shown effective to my knowledge. The latter include either fixed wind machines, mobile orchard fans, or helicopters. Of all those, only the last is of any use if you’re not set up for them yet. Let’s just keep an eye on the weather and hope that we can ride things out for a couple more weeks.

I do want to cast a word of warning that there seems to be a glitch in the NEWA apple scab ascospore maturity model that is showing lower maturity in many orchards than we would expect. Several years ago, the model had a ‘dry switch’ included that paused the model’s spore development prediction in extremely dry weather, which we saw earlier this month. We suspect that’s what we’re seeing, but I’ve conferred with Cornell plant pathologist Dr. Kerik Cox and he agrees that the model seems a bit off. His prediction is that we’re closer to 15% mature ascospores (as seen in Shoreham, with 13% estimated) as opposed to the 4% that is shown for South Burlington. The point of this is to remember that a model is just that- a tool that helps us to organize information, in this case weather and disease life cycle parameters, to make decisions. I know, in the old days, we estimated ascospore maturity by collecting infected overwintered leaves and analyzing spores under a microscope. The time and facilities to do that no longer exist, and ascospore maturity models were developed because of issues with timeliness (you could only assess conditions for the day you did the squash mount) and site-specificity of the old system. My point is, assessing spore maturity, whether by NEWA, RIMpro, AgEye models or direct observation under a microscope is always an estimation. At the end of the day, we need to take the information that we know about the orchard-disease system and make a decision. With apples at tight cluster or later in the main production regions of Vermont, we’re entering the period where I will always recommend preventative, protective coverage prior to anticipated rain events, even if the latest model says that only 4% of overwintering spores are mature enough to cause infection. As Kerik reassured me, the NEWA models tend to behave better in due time when we sink into a more ‘normal’ weather pattern.

It looks like the next chance of rain is Saturday or Sunday, so plan accordingly.

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.

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.

UVM Extension helps individuals and communities put research-based knowledge to work. 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.

NH Virtual Twilight Meeting – 4/28/21

Sharing this meeting from colleagues at University of New Hampshire. The weed management discussion should be especially of interest. -TB

Tree Fruit [Virtual] Twilight Meeting

Wed, 04/28/2021

6:00pm – 7:45pm

Topics: Early Season Disease Management Considerations, NEWA Updates and Tree Fruit Weed IPM

Dr. Cheryl Smith, Plant Health Specialist with UNH Extension will cover early-season disease concerns and management strategies for tree fruit. Apple scab and fire blight management strategies will be highlighted. She’ll demonstrate the updated NEWA website and how to access the forecasting models available via NEWA.

Dr. Besancon will focus on integrated weed management in orchard settings. Foundational information on weed biology, ecology and identification will be presented, followed by strategies for Integrated Weed Management in fruit production. Herbicides selection, timing of application, spectrum of weed control, and potential for crop injury will be included. Time will be allotted for discussion and Q&A in order to tailor the information specifically to grower needs.

Full details and the registration link can be found here:

https://extension.unh.edu/events/tree-fruit-virtual-twilight-meeting

Jeremy DeLisle

Field Specialist – Food and Agriculture

Fruit and Vegetable Team

Merrimack County

315 Daniel Webster Highway
Boscawen, NH 03303

Phone: 603-255-3556 x 805

VT Apple IPM: Likely scab infection period this week

It’s looking like we have a likely apple scab infection period coming midweek in most parts of the state. Anyone who went into the rain / snow with copper or a fungicide, that’s likely gone. We’re also getting into the window where more spores are maturing (aside from cooler upland / inland sites, you probably still have <5% mature spores). Warmer sites should pay attention to this one, and apply a protectant (mancozeb, captan if you haven’t used oil in the past 10 days, sulfur if organic) and consider adding an early-season systemic like Vangard / Scala / Syllit if you aren’t sure about coverage going into the last event. That last suggestion is only for orchards in the warmest regions (warmer / lower elevation parts of Windham / Bennington / Addison counties), As I mentioned before, in most orchards, the overwintering inoculum was relatively low and the ascospore maturity was just starting to get underway before the rain.

With the cool down, we’re back at near-normal bud stage timing, so I’m becoming less concerned about frost to apples. Any time you have to material and sufficient spur leaves to intercept it, plan on applying foliar nutrients (nitrogen, boron, zinc) to strengthen buds prior to bloom.

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.

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.

UVM Extension helps individuals and communities put research-based knowledge to work. 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.