University of Vermont

It’s finally looking like there’s a better than zero chance for rain in the next few days. Everyone, regardless of the status of your apple crop, should be covered going into this (hopeful) rain event. If you have fruit, plum curculio is likely your main pest of concern right now, we’re about a week away from codling moth egg hatch. Keep an eye on your fruit set and if fruit are still clustered up, consider a thinner.

Be careful (or just don’t) with spraying in heat. I’ve done a good bit of damage to fruit and foliage when spraying over 85°. Best window if you can cover the orchard quickly enough is once it starts cooling down tonight through tomorrow. The front coming through will bring wind.

That’s all for now- I have a sprayer to set up.

-Terry

We have been collecting damage data from orchards across the state this week, and the news is generally not good. It does seem like we have three classes of damage: near-complete crop loss inland and Connecticut Valley, some degree of often substantial loss in the Champlain Valley, and a good crop in the Champlain Islands and near the lake. As far as management goes, that leaves us in three different scenarios, and those in one of the scenarios- complete crop loss- may not be crazy about hearing me discuss how the lucky ones tend to their crop this season. I’ll make some notes in a bulleted list without much formatting, as I have more orchards to scout this afternoon:

• Apple scab- This one is easy, it is still active, with no orchards having discharged all overwintering inoculum yet. Wetting events are few and far between but all orchards need to keep covered against scab. Be sure to include a fungicide effective against rust, like a DMI (FRAC code 3) or SDHI (FRAC 7) and/or powdery mildew (strobilurin, FRAC 11) in a couple of sprays to keep those diseases at bay. This protocol should be followed for all orchards regardless of crop freeze status.
• Keep an eye out for fire blight strikes. Any blossom infections that may have occurred from the May 12 potential infection event should be showing now or next week. If you see them, cut them out.
• Thinning is going to be complicated a lot by crop status, of course. For orchards that have no fruit or heavily damaged fruits (meaning more than 75% )do not consider thinning this year. For orchards with less than 20% damage I would consider thinning as normal this year. The question comes with orchards that have moderate damage between 25 and 75%. Not thinning those orchards may result in heavy set of small fruit that could promote biennialism, but trees are likely to respond well to thinners applied in the next week, given both the cold damage and the warm sunny, weather that we are expecting coming up. My tactic at the UVM orchard, which experienced moderate fruit damage between 20 and 70%, depending upon cultivar, was to apply a low rate of NAA thinner with a low rate of carbaryl insecticide. This could be a gamble – we have 70 varieties across the whole orchard and it is difficult to thin based upon variety even in a ‘normal’ year. This is not an uncommon problem for retail orchards to face. I do not have the greatest confidence in this strategy this year, and have difficulty recommending blanket sending recommendations to growers given the state of the crop this year. in the end, I would trust your gut – if you have a good crop thin it, if you have a moderate crop consider thinning it lightly as we can come back in later next week when we can see better the effects of both the frost and any thinner applications you may have applied.
• Insect management-this will also differ, depending upon the state of the crop in your orchard. For orchards with a full or even a moderate crop, I would plan to manage your insect pests as normal this year. Petal insecticide sprays should have already gone on in most orchards. Inland orchards and cooler sites may be ready for a petal fall spray now. Normally our petal fall sprays are targeted at European apple sawfly, early emerging codling moth, and plum curculio. All of those pests are fruit feeders so orchards that have no fruit or are assuming to have very little fruit may consider omitting all insecticide applications targeted toward protecting fruit. The difficult situation comes where orchards have a low set of fruit where the expense of the application on a per bushel basis could be quite high but the value of the few apples you have is also high. If there’s any question about whether or not you have sufficient crop set in your orchard, I would go ahead and treat as usual. If you have no crop or nearly no crop , then you may consider omitting those insecticides. However, I would consider maintaining some coverage primarily for shoot and leaf feeding, lepidopterous caterpillar larvae. That may mean including BT sprays in petal fall, scab, thinning, or other sprays in order to keep down leps like obliquebanded leaf roller and tent caterpillar. In orchards with little to no crop, the great reduction insecticides used this year may allow beneficial populations to increase substantially, setting you up for a better IPM program next year. I would however not ignore trunk applications of Assail or another appropriate insecticide in young plantings to avoid issues with dogwood and other borers.
• Nutrients-for trees with little to no crop nitrogen applications should not go on this year unless trees are under vigorous. For all other trees, fertilize as you normally would. For trees with little to no crop this year potassium is not likely to be removed in any significant amount because that is usually removed in harvested fruit. However, it is important to maintain or improve the potassuim status in your orchards to ensure that you have an appropriate amount of that nutrients going into next year when it is likely orchards, will have a heavy crop load. I would consider applying magnesium potassium fertilizers in the next month or so regardless of crop status.

That’s it for now. I hope to have a better understanding of the crop situation soon, but you all likely know where you stand on your own farms. I will continue to work with the Agency of Agriculture to see what resources we can bring to the industry in this tough year.

Take care,

Terry

The devastating freeze event that nearly all of us saw on May 18 will have a massive impact on the 2023 Vermont apple and grape crops. I have met with Vermont Secretary of Agriculture Anson Tebbetts and representatives from our federal congressional delegation and they are working on finding resources to help support affected farmers. We have been asked to collect as much data as possible to help inform these efforts.

https://go.uvm.edu/2023fruitfreezereport

The UVM Fruit Team has developed an online reporting form to collect this information. This is separate from any assessments that may be conducted for crop insurance purposes- if you are making a claim, please contact your insurance representative in addition to filling out this form.

We also recommend contacting your local Farm Service Agency to establish access to any potential assistance with this event.

It is important that we develop the best assessment of damage possible in the region to inform any efforts to leverage support. These data come directly to me and I will share with the Agency and other organizations anonymously. You may answer any questions that you wish to.

We are asking for general economic impact on your farm, as well as block-by-block damage reports. You can fill out those block reports as much as you want- there are fifteen blocks or cultivars you can report; if you want to report more, just retake the survey and only complete that section. Most important is to report potential crop value lost in the final section.

My graduate student Eli Wilson noted his protocol; for collecting damage in apples. The collection should be similar in grapes but you will be assessing damaged shoots as opposed to fruitlets. Feel free to modify your protocol as you see fit, you will only be reporting percent of fruitlets or shoots damaged.

Apple fruitlet damage assessment protocol.

Be sure to take note of:

1. Location on slope (Top, mid-slope, bottom)

2. Row orientation (North to South, East to West)

3. Cultivar

4. # of damaged fruitlets

Collect a total of ten fruitlets per tree from the bottom, middle, and top of the canopy. Slice the fruitlets in half (vertically) to assess them for damage, any internal brown/yellow tissue or seeds should be considered damaged. Record the number of damaged fruitlets out of ten. Repeat this protocol for every eighth tree in a row and for every sixth row of a block unless you wish to assess a specific cultivar in which case you should add this row to your assessment but not substitute it.

**Attached to this email are images of a healthy fruitlet and a fruitlet with minor cold damage do give you a baseline for your assessments. Any fruit with that level of damage or higher should be include in your damage report**

Figure 1: Healthy apple fruitlet

Figure 2: Damaged apple fruitlet

My team will be available and conducting assessments around the state this week and likely next. There is a lot of ground to cover and we cannot hit every farm so please consider conducting your own assessment and reporting you data in the form. I will be monitoring the form and trying to get to underreported areas as I can, considering my other responsibilities at this time of year.

Please reach out to me if you have any questions,

Terry

https://go.uvm.edu/2023fruitfreezereport

I spent a bit of the day fielding calls and assessing trees from a few counties after last night’s freeze event. Growers in the Champlain Valley largely escaped extensive freeze damage; I doubt Grand Isle County even saw a light frost. This was a textbook lake effect phenomenon. Inland and upland orchards or orchards in lower sites appear to have extensive crop loss, some likely will see a complete loss of crop. Here are a few items to consider as we pick up the pieces:

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 yesterday 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.
6. Thinning could be really easy (no crop, no thinning) or more difficult, especially in blocks with inconsistent fruit set and levels of damage. All things being equal, trees will respond more easily to thinning chemicals after experiencing a freeze. If you have more than 50% damage, consider at most a light thinning protocol this year. More than 80% damage? Leave the thinners out altogether.
7. My suggestion this morning to consider applying Promalin may have been a bit premature or at least lacking in further nuance. My thought at 4 am as I was looking at the temperatures was to offer whatever I could to growers who would need to source a material few to none of us keeps on-hand and get it on the trees within 24 hours. I was not thinking that a) there only existed nine bottles in the entire state, b) many orchards were at petal fall and so were past the phenology labeled for use of the product for this purpose, and c) orchards that got really cold and had 100% crop loss or severe damage from temperature below 24-25° would not respond- a dead bud is a dead bud. I do plan to collect data at the handful of orchards who applied Promalin to see if we can add to the fairly sparse dataset on its efficacy in these situations.
8. If you have no fruit, trees still need to be managed. The important things to stay on top of are apple scab, fire blight if you see any, foliar insects on young trees, and wood-damaging insects like borers. Keep your fungicide program up for the next month or so (is apple scab season ever going to end, despite us seeing next to no scab?). Keep weeds away from trunks, especially if you will be backing off insecticide sprays for fruit feeders like codling moth or apple maggot that would normally help manage borers. Back off or eliminate nitrogen fertilizers- fruit really slow the vegetative growth of fruit trees so when there are none, the trees can be excessively vigorous. Consider applying Apogee or Kudos to reduce vegetative growth and stiffen up cell walls in vegetative shoots to reduce canopy size and make shoots less susceptible to fire blight.
9. Start thinking about your marketing for this season. Many of the most affected orchards are small pick-your-own or retail operations. They may be side gigs or a family’s main income. Most are diversified to some degree. Consider whether you’ll need to buy fruit in and provide customers some other reason to visit the orchard- foliage hay rides, corn maze, pumpkin patch. There are fruit in the region that can be brought in, so start making those connections and thinking about how you’ll keep cash flow this fall.

I have been a member of the Vermont orchard family for almost 30 years now, and I am always impressed with the camaraderie and collective sense of purpose that we share. These events can be major hardships, potentially even devastating. Let’s see how we can help one another and keep this incredibly important industry, and each and every farm within it, afloat and even thriving after a challenging, somewhat unexpected event that could have affected any of us.

Please reach out if you need anything,

Terry

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.

As I scan the temperatures around the state on Weather Underground this morning, it looks as I expected, that most orchards are likely fine (no damage) or okay (a little tolerable damage) after the freeze event we’re in. Some orchards however, especially inland and upland, and really especially inland and lowland (in lower areas where cold air settles), may have experienced substantial damage. Promalin plant growth regulator is labeled and has shown some efficacy when applied to trees at bloom to early fruit set for maintaining fruit development after a frost or freeze. Promalin is a gibberellin and cytokinin PGR mix that essentially fools the fruit into continuing to develop in the absence of a hormonal signal from seeds that were damaged or are not present if the ovary was damaged. Applications within 24 hours after the freeze are most effective.

If your orchard experienced temperatures below 28°F, consider contacting your agrichemical dealer asap this morning and applying Promalin. Label rate is 1-2 pints per acre in 75 to 150 gallons of water per acre.

Terry

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.

Vermont orchards and vineyards are in varying states of vulnerability and likelihood of frost damage going into tonight’s expected cold event. At UVM orchard in South Burlington, we are at about 50% petal fall on McIntosh and the vineyard is at about one inch of shoot growth; inland and upland orchards are at or even approaching full bloom and vineyards are hovering around bud break. All orchards in the state are at risk for blossom tissue damage with temperatures at or below 28°F, and potentially a full crop loss around 24-25°F. Vineyards with fully emerged buds (1-2 leaves or more) are at the same risk, but those at bud burst or behind are less susceptible to damage and may do okay even into the lower twenties. In the Champlain and Connecticut River Valleys, expected lows are in the 30-32°F range, and orchards should be okay except possibly in low-lying pockets. Inland and upland, this event will likely show where site selection leaves orchards at most risk. Some inland orchard sites are calling for lows in the 24-25° range- that could cause substantial damage. Winds are expected to calm down overnight which lends to increased frost risk in low areas where cold settles. This does mean that methods that stir up air inversions may help- wind machines, helicopters, etc.- but few of our farms are set up for that aside from the lone wind machine I know of in Shoreham which I expect will be running in the early hours of tomorrow morning. There is little you can spray to affect frost tolerance of plants- some materials like some copper formulations and some potassium fertilizers are either labeled or purported to improve bud hardiness but not when sprayed right during a cold event and the science isn’t very good on that, either. Not to mention that sprayers will be icing up if you try to spray at 10-11 PM or later when the winds calm down, as that’s when the cold (below 32°, when spays will start freezing) is expected.

Growers could try burning round bales in the lowest / coldest parts of the plantings, starting around midnight or whenever the temperature starts to get down to 28°, but that isn’t known to be especially effective as the heat needs to radiate across a large area to really have any effect, and the smoke and near-range heat from burning bales can damage developing buds. If you have a Frost Dragon or similar device, tonight would be a good time to run it. But who has one of those in Vermont (I’d love to hear from you if you do).

The best case for most may be to wait this out and to conduct an assessment tomorrow afternoon or Friday. This article provides some good pictures of damaged tissues to compare yours against.

https://www.canr.msu.edu/news/assessing_frost_and_freeze_damage_to_flowers_and_buds_of_fruit_trees

Understanding the extent of damage will help with reporting for crop insurance purposes or to adjust you fruit (apple) or shoot (grape) thinning needs.

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.

Good afternoon. UVM Fruit Program M.S. student Bethany Pelletier has written this week’s message. -TB

For many of us, bud break came up quick here in the Champlain valley. This means a real push to make sure your pruning has set you up for a clean, orderly season (or as much as we can hope). Make efforts to get your vineyard as sanitized as possible, getting old wood cleared and well away from your working plants to reduce as much of last year’s inoculum as possible. Fungal disease loves to sit in that old grape wood, so leaving it laying in the vineyard can have you fighting an uphill battle.

Speaking of inoculum, get your sprayers ready! Those with organic spray programs or with heavy disease pressure from previous years will want to begin your spray program around 3” of growth. For us here at the UVM Horticulture Research and Education Center, this likely means a spray sometime next week before a rain event. For those with a good handle on your disease pressure and using highly effective fungicides, you can get away with waiting until 5-8” of new growth.

As for what to spray, keep in mind what we are working against. Our key early season disease is Phomopsis, but we’re keeping in mind any downy mildew or black rot as well. Anthracnose is also an early season disease, and while not present in all vineyards those who have it should also be spraying for it at this time. Key fungicides in your arsenal against these early season diseases may include mancozeb, captan, or ziram. For organic growers, copper has shown some efficacy, but good sanitation practices are really your first line of defense here.

With nervous excitement, I am happy to be starting this next season of grape growing! I wish a sunny and not-so-rainy spring to you all! -BP

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.

We are expecting a slight warmup later this week that may push levels of fire blight bacteria high enough to be concerned about infection in blooming orchards. While this event does not look like a ‘high alert’ scenario, and chance of rain is relatively low but still there for Friday, all growers with trees in bloom should keep an eye on NEWA and be ready to treat orchards with open blossoms with streptomycin ahead of an infection period. Apple scab continues to look like a non-issue for as far as the forecast goes, but be prepared to be fully covered before the next significant rain event. NEWA is not suggesting that the low-likelihood, short duration rain that might come tomorrow Friday May 12 will be enough to cause an apple scab infection period. My take- hold off on spraying unless you are in a high fire blight risk situation and you get wetting tomorrow, then apply strep. There’s no need for fungicide at this time but we’re just getting into the season with plenty of spores left to discharge due to the dry weather. The next good rain will likely result in a big infection period and, with the rapid growth we’re seeing at this time of the year, you want your spray coverage as close to the infection period as possible to ensure that new growth is covered.

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.

Buds have been breaking in Vermont vineyards in the past week, which signifies the real start of the growing season. This brings up a few pest management considerations for your vineyards. Most cold-climate cultivars will not need disease protection until 5-8” of shoot growth, but any vineyards with heavy disease pressure last year may wish to begin as soon as shoots are 3” in length, especially if inoculum reduction through thorough removal of diseased wood and mummy berries and/or dormant application of lime sulfur was not performed. Since we all likely have a week or two before we need to get out there, now is a good time to make sure that your equipment is ready to go. I still recommend our Initial IPM Strategy for Cold Climate Grapes as the best resource to boil the decisions down to a simple ‘prescription’, with the caveat that since it was written some new pest management materials have been released and inoculum may have increased in your vineyards which could lead to increased disease pressure. Growers should have an up-to-date copy of the New York and Pennsylvania Pest Management Guidelines for Grapes as a reference for specific materials, their efficacy, and use considerations. Remember however that the guidelines are written largely for vinifera and less disease-resistant hybrids, so the specific spray programs recommended may be overkill in Vermont vineyards.

The warm weather in the next few days may increase emergence of grape flea beetle or cutworms. Grapes are susceptible through about the one inch shoot growth stage, so this could be a short window and the vines may well outgrow any threat pretty quickly. A scouting of your vineyard for feeding on swelling buds or developing shoots may be warranted. If damage is evident on more than 2% of buds, an insecticide treatment may be warranted. But if shoots expand rapidly over the week, don’t worry about this pest.

Since buds at ground level have begun to emerge, applications of systemic herbicides should either be halted or very carefully controlled to prohibit contact with green tissue. Now is an appropriate time for cultivation in vineyards to manage weeds. It’s also a good time to keep water on newly planted or young vines. With soil warming and growth beginning, nitrogen fertilizer applications, if needed based on foliar analyses or observed low vigor last year, may also be made now.

With orchards in the Champlain and Connecticut valleys heading into bloom now and even inland/upland orchards expected to show some blossoms later this week, it’s ‘go-time’ for setting up the 2023 Vermont apple crop. We are thankfully looking at an incredible week- sunny and 60s or 70s every day as far as the outlook goes, and cool but not cold nights expected, no rain. If ever there were a Goldilocks bloom season, this is it.

It goes without saying but I will say it that we don’t need to be spraying any insecticides heading into bloom. If you are at early pink stage at the latest and if you have a documented population of tarnished plant bug or European apple sawfly and if your markets can’t absorb a little cosmetically-damaged fruit (i.e., if you sell to wholesale markets) and if you have mowed all flowering weeds like dandelions that would be bringing pollinators into your orchard now , then a low-residual non-systemic (i.e., non-neonicotinoid) insecticide may be applied to manage those pests- but that’s a pretty small Venn diagram I described. Given the dry weather, I don’t see any need for a fungicide, assuming that you were covered during last week’s long apple scab infection event. The cool weather looks to be keeping fire blight bacteria at a low epiphytic infection potential so we can’t expect that disease to be an issues- but pay attention to NEWA this week as the bacteria that causes the disease can rapidly multiply if the weather warms and open blossoms would need treatment with streptomycin or a biological material (Blossom Protect, etc., only recommended for organic orchards as the efficacy is much lower than strep).

This is a good week to get irrigation going. This would also allow for fertigation of important nutrients, especially nitrogen and boron that are in high demand with the flush of new growth we see at this time of year. Finally, I hope to see some of you at the Apple Pollinator Workshop at 4:30-6:30 on Wednesday, May 10 at the UVM Horticulture Research and Education Center, 65 Green Mountain Drive, South Burlington VT.

Apple meeting agenda for 5.10.2023 twilight meeting.pdf