IPM – UVM Fruit Blog

Vineyard Management at Veraison

August 4, 2020

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. Marquette veraison, 8/3/2020. UVM Catamnount Vineyard, S. Burlington, VT.

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.

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 closest analytical lab for grape petiole analysis is the Cornell Nutrient Analysis Laboratory . Please note that they now have partnered with Agro-One Services. It is recommended that you contact them before you send any samples to confirm that recommendations will be sent along with the analysis and to confirm costs.
Video about petiole sampling: https://www.youtube.com/watch?v=8EHbojLfXek

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 2010-2015. 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

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.

Grapes Download

Vineyard Management at Bloom

June 17, 2020

I’ve visited some vineyards from the higher-elevation interior of the state to the Champlain Valley in the past week. Champlain Valley grapes are entering or even well-into bloom, upland and inland are around 5” shoot growth stage. Bothe are at key management points, so it’s best to spend some time in the field in the coming week. If it hasn’t been done, now is the time to thin your shoots out to 3-5 per foot of canopy length. That’s a pretty gross rule of thumb, it might be better to adjust down to a per acre target and go from there, especially if your vines aren’t completely linear. I’ve seen a couple of instances where established VSP / mid-wire cordon vines are being shifted to a top wire cordon training system. Those vines have plenty of vigor to hold a decent crop, but the canopy is in a middle-stage and shoots originate from all over the place. In that case, consider a target harvest per acre and count back from there. Day you want 3.5 tons, or 17,000 lbs per acre. You have 800 vines per acre on a 6 x 10 foot spacing. (Calculating vines per acre = 43,560 square feet/acre / (in-row spacing (ft) * between row spacing (ft) or 43,560/(6*10) = 796). That means you’ll want 21.25 clusters per vine. If your clusters average about 1/3 lb each, that’s 60 clusters to keep per vine. Then, you’d thin out shoots to select the most uniform and appropriately-spaced ones to get to that number. In many cases where vines give you two clusters per shoot, that would leave five shoots per foot of canopy (or 30 shoots on our six-foot vine).

Just as important as getting your shoots and cluster numbers in order is disease management. We’re blessed to be in such a dry spell during this critical period for disease, and I’ve seen remarkably little disease even on minimally-sprayed vines. But we’re in the prebloom and soon, postbloom window where all of the major grape diseases are primed to infect. Chances of rain are increasing as we move into the weekend and beyond, so it’s important to get things covered this week. Be careful spraying in hot weather, for two reasons. First, a properly-protected spray applicator (Tyvek suit, gloves, goggles, etc) is at risk for developing heat-related health problems, so spraying at dawn or even at night can help. Second, some of the more phytotoxic materials like captan, sulfur, and copper can cause more plant damage when applied just before a heat wave. Spray material choice is dependent on your management system, I recommend our Initial IPM Strategy for Grape Growers fact sheet in general, and specifically for non-organic growers. Regardless of system (organic or non-organic), this is the time to use your best tools available. For non-organic growers, that would be a protectat and single-site fungicide combination, like mancozeb or captan plus a strobilurin (e.g., Flint) or DMI (e.g., Rally) or SDHI (e.g., Aprovia). Note for that last part of the mix, there are also some good pre-mix combinations like Luna Experience (SDHI + DMI) and Pristine (Strobilurin + DMI) that can cover a lot of bases while reducing resistance development in the target pathogen.

For organic growers, I’d also consider a two-part mix. Regalia has been getting a lot of interest lately and it does appear to have good efficacy against downy and powdery mildews. It needs to be applied 1-2 days before infection, and requires sunlight to activate resistance in the plant- spraying the night before a wetting event won’t do it. Regalia can be mixed with sulfur or copper (more on those two later). Serenade is another biological product which is approved for organic production. Its mode of action is as a microbial antagonist to the pathogen, so it must get established and colonize susceptible tissue before wetting and infection events. Because of this, Serende is not compatible in a tank mix with sulfur or copper, but it could be rotated with them in separate sprays. Serenade has most efficacy (good but not excellent) against powdery and downy mildews. However, it does not protect against some key diseases that affect grapes during this window- anthracnose (especially important on Marquette), Phomopsis, and the most difficult to manage organically, black rot. For those diseases, copper has a bit more efficacy, so this is one spray that should include it, if the vines aren’t sensitive to it. Cold-hardy hybrids with considerable labrusca in their parentage (e.g., St Croix, Brianna, other Swenson varieties) are more sensitive to copper than some others. However, copper damage can be reduced by avoiding application during slow drying conditions (there goes my recommendation to spray at dawn…). As always, spraying should be about your fourth line of defense when managing grapes organically- first consider http://www.uvm.edu/~fruit/grapes/gr_ipm/RelativeDiseaseRatings2017.pdfsusceptibility; then strict weekly sanitation and removal of all diseased tissue; maintain a training system that ensures good air flow; and finally fit a spray program to help manage within that greater IPM (yes, organic systems are IPM too) program.

Finally, this is a good time to consider applying micronutrients to the vineyard. Boron is very often deficient in Vermont soils, and is needed for fruit development at bloom. The best way to assess need and amount to apply is with a recent petiole sample analysis (last year’s, although you could sample at bloom and make a quick correction). Without that, I feel safe recommending 1 lb per acre actual boron (5 lbs per acre Solubor, an OMRI-certified boron source with 20% B) applied in your spray water. The only caution I make there is that boron and water soluble packaging materials (like Rally bags) do not mix- you’ll gum up your sprayer and ruin your day. Apply those separately. Also, this is a pretty low rate of boron I’m recommending, as you can overshoot pretty easily so I do recommend a petiole analysis to tune your application rate before adding any more.

Finally, Wild grape bloom occurred on June 5 in South Burlington, which sets the clock for grape berry moth management. The first overwintering generation is rarely significant enough to warrant a management spray except in vineyards that have had extreme damage in previous years. Each generation requires about 820 degree days (base 47°F, or DDb47°F) to complete, and the first generation typically emerges around the time of wild grape bloom. So if we use June 5 as our ‘biofix’ and track DDb47°F, we can estimate the best time to treat for the more damaging later generations.

This is made easy by the Network for Environment and Weather Applications (NEWA) system, which I coordinate for Vermont. The network includes twelve on-site weather stations (all located at orchards) and six airports, and imports data in near real-time for use in pest models. It is free to use, and growers can locate the site nearest them and develop a best-guess of phomopsis, black rot, and downy mildew infection periods as well as a sense of the grape berry moth generational development.

Early Summer Vineyard Management

June 29, 2020

July 1 brings a number of early summer vineyard tasks to think about. First, be sure to keep up with your disease management: sanitation, especially in organic vineyards, and sprays as needed. We’re still in that critical window where all or the main diseases (except maybe Phomopsis) are active. See our initial diseases management guide, or the New York guide for details. Also, the material in Cornell professor Katie Gold’s early season disease management recommendations is still relevant.

As for horticulture, there are a number of activities to stay on top of. Petiole samples to assess vine nutrient status may be collected now where vineyards are in bloom, or at veraison. Stick to the same timing in your vineyard if you are going to compare samples year to year. Details here. Keep vines, especially young or struggling ones, watered during this drought. Manage weeds, especially, again, on young vines. Established vines tend to compete better for water and nutrients, but tall weeds growing up into the canopy will increase disease pressure.

Finally, shoots will soon lignify at their bases and be strong enough for combing without breaking them off. The goal, for vines on a high wire cordon system, is to separate each shoot and direct it downward, thus exposing fruit to sunlight and making a more manageable canopy. Once shoots are pointed in the right direction, it’s easy to see where runty secondary or tertiary shoots are in the canopy, and where smaller clusters that are behind in development compared to the main crop are- those can both be removed.

(Retired) Iowa State Extension Specialist Mike White presents a good overview of the concepts and practices behind canopy management in his February 8, 2012 newsletter found here.

There’s a video of some UVM staff doing some (silent) canopy management here.

Ohio State Extension has a nice video here.

Vineyard Management

June 7, 2020

First, sorry about lumping the grape growers in with my last apple email. I do know that you’re (mostly) separate entities with separate needs. That said, the importance of staying on top of disease management now is just as much there. We’re entering the critical immediate prebloom period in vineyards, when they are susceptible to pretty much all of the major diseases we face: black rot, Phomopsis. Powdery mildew, and early downy mildew. For non-organic growers, and combination of a protectant (captan or mancozeb) and a systemic / ‘kickback’ active material like a strobilurin, DMI, or SDHI would be warranted now and in the next application 7-10 days fr4om now. Be sure, especially with that latter group of materials, to rotate fungicide resistance classes so that you’re not using any class (e.g., 3 for DMIs, 7 for SDHIs, and 11 for strobilurins) more than twice back-to back. Some materials have more restrictive seasonal application caps- always check your label. For organic growers, I would recommend rotating copper and Serenade or bicarbonate (like Armicarb O or equivalent) on a fairly tight 5-7 day schedule. Then again, the dry weather has been nice for managing diseases. Organic growers need to really pay attention to sanitation and removed any diseased tissue as soon as it’s seen, and scouting should be done weekly.

I saw a good bit of grape tumid gallmaker in our UVM vineyard last week, enough that we treated for it. Usually, this insect is a curiosity, but we have seen and had others report that losses can be as high as 50% of fruit clusters ruined by the insect. Keep an eye out for it (pictures in the link posted) and consider treatment if more than 5% of fruit clusters or 15% of leaves are affected. Organic growers will need to crush galls by hand, non-organic can treat with Movento or Assail.

Get your shoots thinned. This will make life so much easier later this summer.

Vermont Orchard Rundown

June 7, 2020

I had a chance to visit some orchards late last week in Southern Vermont. We should remember that the lower Connecticut River Valley has traditionally been a major center of apple and peach production in the state. While there are fewer acres of trees than in the past, that’s true across the state. I am always impressed by the landscape down there, it really feels like another place compared to the Champlain Valley or interior highlands. What I saw is likely pretty indicative of orchards around the state.

Fruit set looks pretty heavy, and I have been seeing evidence of thinners applied early last week working. We are entering another window of good thinning weather, so if your crop id still clustered into doubles and triples per cluster (or worse), plan on another thinner this week before it warms up again. Grower who use Apogee for shoot growth management should keep applying on a 10-14 day schedule until terminal bud set. That’s still a solid month away. Get your nitrogen, potassium, magnesium, and boron fertilizers (plus anything you need if your foliar analysis from last year indicates it) on now. Any time, you can start applying calcium sprays to developing fruitlets, especially Honeycrisp and other large-fruited varieties.

Diseases: scab? What scab? This spring has been easy to manage for apple scab, as rains have bee intermittent, spread out, and fairly short. NEWA suggests that most of the ascospores at our orchard in South Burlington have been ejected, but I don’t really trust that yet. Growers should maintain fungicide coverage ahead of any rain events for the next couple of weeks. Fire blight: I started seeing symptoms on Friday in one of our blocks that was intentionally inoculated as part of Dr. Kerik Cox and Anna Wallis’s fire blight trials I am hosting. So, I know conditions were ripe for infection. Keep an eye out in your orchards and be ready to cut out any strikes as they appear. Haste is good on that front. Sooty botch / flyspeck will be managed with your scab sprays.

Insects: Things are hopping on that front. Plum curculio remains active and I have seen injury. We’re only about halfway through their oviposition period at this point, so keep covered. Organis corchards should plan to keep Surround on for another couple of weeks anyway. Codling moth are active. If you didn’t trap them in your orchard, use the NEWA models to guess, but it’s always best to use an actual catch date from your farm when calculating degree days for managing this pest. I’ve played around with a few capture dates for various orchards in the warmer sites and all are calling for treatment sometime this week. If CM are a problem in your orchard, I would plan on a spray specific to them with a selective and efficacious material like Intrepid, Rimon, Belt, or Madex. As always, see the New England Tree Fruit Management Guide for recommendations.

Orchard Considerations: Scab (yes…), Fire Blight, Insect Management

June 17, 2020

It’s dry, I know. If you have the ability to irrigate, you should be. At a minimum, newly planted trees should be watered regularly. This dry weather has been great for management of most diseases- apple scab, plus rusts and some of the other ‘minor’ diseases should be pretty low in abundance in managed orchards. It’s not hard to find scab lesions in unsprayed orchards, even at the especially-dry UVM Horticulture Research & Education Center (HREC), so the potential is there. This dry weather is slowing the end of scab season, though. Ascospore development follows a fairly predictable curve in years with normal precipitation patterns. However, in dry conditions, the fungus enters a dormant state, so development slows. We’re not entirely sure how extended the dry window needs to be for the inoculum to die out rather than just wait it out until rains come and re-energize it. Most orchard’s NEWA models indicate that the primary scab season is over, but others who are using the RIMpro model indicate another infection period is waiting in the wings. I would feel better with one fungicide protection going into next week when rains are expected. I don’t know if any of the models adequately plan for weather conditions like this.

The disease of greater concern to me is fire blight. Weather during bloom was hot this year with pretty high potential for infection. However, wetness events were rare, and inoculum isn’t guaranteed in all orchards. We have some active fire blight research going on at the HREC, and I can assure you that trees that were inoculated have plenty of the disease. We also have other sections of orchard with little FB history where I have found a few strikes. Everyone should keep an eye out and do a thorough scouting of your orchards for signs of infection and plan to cut it out ASAP. This dry weather we’re having is conducive to cutting while minimizing disease spread. Dan Cooley and others wrote a nice fact sheet on fire blight management that can be found at: https://ag.umass.edu/sites/ag.umass.edu/files/fact-sheets/pdf/f-133.pdf. I have also recorded a video on removing strikes that I’m posting to my YouTube channel (https://www.youtube.com/user/UVMOrchard). My rural DSL upload capability is taking quite a while to get it there, so check back later today.
Insect management is key in orchards now. Where codling moth has been a problem, application of a CM-specific material is warranted most any time now, depending on your biofix (the date of first catch in pheromones traps in your orchard). For upland and inland sites, you may be a week away. Plum curculio are likely still active in cooler sites, but I have not seen fresh damage in the warmer sites (Champlain / Connecticut Valleys) so if a suitable material was applied in the last week or so, you’re probably covered there. 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.

Think about applying calcium in all of your sprays now, especially on Honeycrisp, Cortland, and other large-fruited cultivars, and especially especially on those cultivars if they have a relatively small crop this year.

Many growers, myself included, have observed poor fruit set or over thinning this year. That warm spell around June 4-6 and again 10-12 seems to really have activated thinners, and there may have also been some frost damage going into bloom. I hope your crop has turned out okay, please let me know if there are issues. I’m not sure if weather events contributed to overthinning is an insurable loss under most crop insurance policies, but it’s worth looking into.

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, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.

Midsummer Orchard Activities

July 15, 2020

It’s been a while since our last check-in. One of the things I was surprised by when I started in orchard work was the relative slowdown in urgency after July 1. Having grown up on a dairy farm, where there’s no break, and summer means haying season on top of all the other chores, a chance to take a breather in summer is welcome.

But that doesn’t mean there’s nothing to do in the orchard, and activities done (or not done) now can greatly affect your crop. Here are some of the things to keep in mind right now:

Insects: Apple maggot fly (AMF) is active in most Vermont orchards. Red sticky traps should have been hung at the beginning of the month, and five flies per baited trap, or one if not using baited lures, should indicate a need to treat. Assail is the most common material that growers are using these days, although many others are also effective. As always, see the New England Tree Fruit Management Guide for specific details. Organic growers may have success using Surround at this time, although the residue will need to be removed from fruit at harvest. Entrust has some efficacy against AMF, but should be used with a feeding stimulant like sugar to increase feeding by flies. Codling moth (CM)second generation egg hatch is still a bit away, we usually aim for treatment around 1260 degree days (base 50F) after the first trap capture biofix (we’re at 907 in South Burlington as of today). Obliquebanded leafrollers should be active soon as well, and I’d imagine that materials applied to target CM (unless using very specific materials like codling moth granulosis virus) will take care of hatching larvae.

Mites aren’t really insects, but I’ll include them here. The hot, dry weather has been very conducive to mite population flare-up, both for European red mite and for two-spotted spider mite. These pests are worth scouting for, and an average of over 5 mites per leaf (choose mid-aged leaves on terminals) may warrant treatment. The best ways to avoid mite problems are measure to protect beneficial mites and insects that eat them. That means avoidance of pyrethroid, carbamate, and organophosphate insecticides in general, as well as a thorough oil treatment in spring. Still, if you are in mite trouble, there are many materials available to help manage them.

Diseases: Apple scab should be done, it was a pretty easy year on that front. Sooty blotch and flyspeck are now the main cosmetic diseases, along with bitter rot and black rot that can destroy fruit. Although it’s dry, maintaining a minimum residue of a fungicide like Captan, Topsin, or a strobilurin will help to keep diseases at bay until harvest. We’re on a three-week schedule at the UVM orchards, but it’s really dry there and we do not wholesale fruit so a little cosmetic damage from SBFS is acceptable. Finally, keep looking for and cutting out fire blight.

Horticulture: Now is the time to start summer pruning to get some sunlight into vigorous trees and improve airflow and spray penetration. In most cases, summer pruning may not be necessary except to correct for occasional broken limbs or branches growing out into the drive row. But in many Vermont orchards where semi dwarf trees are still common, a light haircut can improve light penetration, red fruit color, and overall pest management and fruit quality. I tell my pruners that I want to see the whole trunk- that means removing vegetative shoots tat are blocking light from penetrating into the tree canopy. Fruit don’t need to be 100% exposed, dappled light is okay, but they can’t be in the shade.

It’s important to be maintaining calcium sprays, especially on large-fruited cultivars and doubly especially on Honeycrisp. Four to eight applications are recommended, especially on Honeycrisp, to reduce bitter pit. That may mean making extra trips through the orchard just to spray calcium. Most times, it can be mixed into the tank with other pesticides, as long as any pH requirements are met for the materials you’re using.

Keep running water if you can. It’s really dry out there, not that you need me to tell you that.

COVID-19: As harvest nears, I’ll get more materials out regarding impact of the pandemic on farm operations. For now, I’ll point you to Verm Grubinger’s excellent resource list for vegetable and berry growers. You will need a plan this year, whether harvesting for wholesale, selling retail, or opening for PYO.

Webinar on Fungicide Resistance by Dr. Michelle Moyer, Extension Viticulturist, Washington State University, on June 24

June 22, 2020

Inviting everyone to this webinar on fungicide resistance management. While it’s tailored for grapes, this is just as important for apple growers. No VT pesticide recertification credits are available for this.

From: Wine Grape Newsletter On Behalf Of psuwineandgrapes@psu.edu
Sent: Monday, June 22, 2020 11:07 AM
To: WINEGRAPE-L@LISTS.PSU.EDU
Subject: [WINEGRAPE-L] Join us for a live webinar on Fungicide Resistance by Dr. Michelle Moyer, Extension Viticulturist, Washington State University, on June 24

Please join us for the Fungicide Resistance and the Acronyms live webinar.

To be covered: In this live webinar, Dr. Moyer will cover the acronyms FRAME, FRAC, and Rotating MOAs, how fungicides are categorized, how those categories function, and how to best use those fungicides based on how they work. Fungicides, of all forms, are important tools in the management of grape diseases. But like all tools, they need to be used as intended and properly maintained. She will discuss how these tools become broken and how to go about repairing them if, or when, they break.

Speaker: Dr. Michelle Moyer, Associate Professor and Extension Viticulturist, Washington State University.

When: June 24, 2020 (3:00 PM – 4:00 PM ET)

To register: https://bit.ly/36Hk2ra

Credit Information: 2 category pesticide credits (PC, 02, 18) will be offered to PA licensed applicators upon completion of this webinar.

Foliar Nutrient Analysis, Pest Management, and COVID-Related Items

July 29, 2020

As the calendar flips to August, it’s time to wrap up field activities in preparation for harvest in Vermont orchards.

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/
(2) University of Massachusetts Soil and Tissue Testing Lab: https://ag.umass.edu/services/soil-plant-nutrient-testing-laboratory
(3) Cornell Nutrient Analysis Lab: http://cnal.cals.cornell.edu/

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 one fly per unbaited trap, or five flies per trap if apple volatile baits are used. Codling moth are entering their second flight in many orchards, so management is advised if this pest is a problem for you. Insecticide options are listed in the New England Tree Fruit Management Guide. Dr. Arthur Agnello discusses 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. Except on later-harvested cultivars, a fungicide application made by mid-month should provide good control through harvest. For retail orchards, fungicide sprays are likely wrapped up by now.

Remember to watch pre-harvest intervals on all products at this time of year.

COVID concerns- I think that many orchards will benefit from others’ wisdom as we prepare to reopen our farms for the season. Every farm must comply with State of Vermont guidances for general business, plus farm markets and/or pick-your own operations. Guidance can be found at: https://agriculture.vermont.gov/covid-19-information/covid-19-sector-guidance-news. I encourage farmers to visit other operations that are now open and see what’s working- parking, stand layout, customer education, etc. Consider this a way to make efficiency improvements in your retail farm operation, if anything.
Specific guidance for agricultural workers, which relates to both domestic, and H2A labor, as well as to workers that both live on and off the farm, must also be followed. Presently the CDC guidelines are the standard that Vermont farms are expected to follow: https://www.cdc.gov/coronavirus/2019-ncov/community/guidance-agricultural-workers.html. Those guidelines include many of the steps that we are already getting quite used to (bullet points taken from CDC website):

Management in the agriculture industry should conduct work site assessmentsexternal icon to identify coronavirus disease 2019 (COVID-19) risks and infection prevention strategies to protect workers.
Work site guidance for COVID-19 prevention and control should be taken into consideration in employer-furnished shared worker housing, transportation vehicles and work settings.
Prevention practices should follow the hierarchy of controls, which includes using source control and a combination of engineering controls, administrative controls (especially proper sanitation, cleaning, and disinfection), and personal protective equipment.
Grouping workers together into cohorts may reduce the spread of COVID-19 transmission in the workplace by minimizing the number of different individuals who come into close contact with each other over the course of a week, and may also reduce the number of workers quarantined because of exposure to the virus.
Owners/operators should maximize opportunities to place farmworkers residing together in the same vehicles for transportation and in the same cohorts to limit exposure.
Basic information and training about infection prevention should be provided to all farmworkers in languages they can understand.
Agriculture work sites developing plans for continuing operations where COVID-19 is spreading among workers or in the surrounding community should work directly with appropriate state and local public health officials and occupational safety and health professionals.

Apple Maggot Fly Traps Should go up; End of Scab??

By Terence Bradshaw

June 25, 2020

Hopefully everyone had some fungicide coverage on for that last rain we got yesterday. It’s hard to tell without doing proper spore counts, but I feel pretty confident saying that primary scab season is done for this year. Scout your orchards for lesions and protect from secondary infections if you find any. But really, this has been a pretty easy scab season.

Keep looking for fire blight and remove as soon as you see it. If you have any big outbreaks, let me know. My Cornell colleagues Dr. Kerik Cox and Anna Wallis are collecting samples of fire blight-infected tissue to test for antibiotic resistance in the pathogen. If you can participate, I’ll be happy to help with collection and shipping if I can do it in a timely manner.

If codling moth is a serious pest in your orchard, you may be due for a second treatment with an effective material. Otherwise, you’re likely in between insect concerns until apple maggot and/or obliquebanded leafroller come around. Now is the time to get apple maggot fly (AMF) traps up. 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.

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. 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. For monitoring 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.

Think about including calcium in all of your foliar sprays until harvest, and on Honeycrisp and other large-fruited varieties, you may want to make some specific trips just to get more Ca on.

Blog-attachment-6-25 Download