Author: Terence Bradshaw

Important Cider Apple Grower Survey- Due September 30

I know it’s a terrible time to ask growers to complete a survey, but we have some project timelines to meet and would like to get an assessment of the status of cider apple production in New England and eastern New York. With a day of rainy day ahead of us (in Northern New England, anyway), this is a great time to complete the survey and help us to continue to evaluate cider apple production in the region. It should only take about ten minutes to finish.

https://go.uvm.edu/necidersurvey

This survey is concerned primarily with cider apples that were intentionally grown for making hard cider, as opposed to cull dessert fruit cultivars, i.e., off-grade McIntosh, Cortland, etc. that were intended for fresh market sales but sold to cideries at marketing time due to reductions in fruit quality or similar factors. Your cider apples may be of European cider cultivars, heirloom varieties, or even dessert fruit but should be managed as cider apples separate from your fresh market apples, if grown.

Thank you in advance, especially for the timing and short turnaround. I would like to summarize the data in early October, so a September 30 deadline is best.

https://go.uvm.edu/necidersurvey

Terry Bradshaw, University of Vermont Fruit Program

Project Director, New England Cider Apple Program

It’s time to consider ReTain applications in Vermont orchards

The use of plant growth regulators to help with harvest management and improve fruit quality is an important tool in many orchards. ReTain plant growth regulator is used to slow ethylene synthesis in ripening fruit to delay maturity and reduce preharvest drop. Given the dry and hot conditions experienced this summer, drop potential is high, and growers should plan on treating their orchards more often than not. One or two applications may be made at the rate of one pouch (11.7 oz) per acre each. Application 21 to 28 days prior to normal harvest will delay ripening 7-10 days and improve fruit storability. ReTain is especially recommended on McIntosh, and reduced rates (1/2 pouch each application) suggested for Macoun and Honeycrisp. ReTain also improves fruit quality on Cortland and Gala. ReTain is not just for fruit destined for wholesale markets. In fact, it is an excellent tool to help stretch harvest out and reduce ‘Monday morning drops’ in U-pick blocks. It also helps to maintain fruit quality both on-tree and in short-term storage.

Jim Wargo from Valent USA has a good list of specific recommendations for ReTain use here.

Late summer orchard meeting next week, Granville, NY

Passing this on from our colleagues at Cornell Cooperative Extension. -TB

ENY Late Summer Orchard Field Meeting

August 16

2:00pm – 4:00pm

Join us for a late-summer field meeting. Cornell researchers and extension specialists will give talks on management tasks to be mindful of late in the season as we head into harvest. We will then walk through the orchard to look for some of the issues discussed, and further discuss their management strategies in the field. We will then discuss how the crop is shaping up around the greater ENY region, and will allow ample time for you to share your thoughts on this year’s crop, and to answer any other questions you may have.

1.25 DEC credits are available for this meeting. Please register ahead.

Contact Mike at 518 410 6823 or mrb254 with any questions.

Agenda

2 – 2:10 pm – DEC Sign in, Welcome, and Introductions – Mike Basedow

2:10 – 2:30 pm – Late Summer Disease Management – Dr. Kerik Cox

2:30 – 2:50 pm – Late Season Insect Management – Dr. Monique Rivera

2:50 – 3:05 pm – Late Season Orchard Physiology – Dr. Jason Londo)

3:05 – 3:15 pm – Bitter Pit Updates – (Dan Donahue)

3:15 – 3:25 pm – Late Season Weed Management – Mike Basedow

3:25 – 4:00pm – Orchard IPM Walk and Talk

4:00 – 4:30pm – 2022 Preharvest Crop Status Updates Roundtable

4:30pm – Meeting adjourn

Register here: https://enych.cce.cornell.edu/event_preregistration_new.php?id=1691

Veraison activities in Vermont vineyards

Grapes are at or near veraison in Vermont vineyards, which signals the start of fruit ripening. At the UVM vineyard, we have observed Marquette at veraison as of August 4, Petite Pearl and Itasca are changing color about now, and Verona is just around the corner.

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

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

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

Start making plans for harvest and crush now. This may be a good time to thin out any lagging ‘green’ clusters that developed from secondary buds and are lagging in ripeness. Remember, you’re looking for crop uniformity. You can estimate yield by counting clusters on a few representative vines and multiplying by the typical cluster weight for your vineyard. If this is unknown, use 0.25 pounds (113 grams) per cluster, which is the average we have recorded at the UVM vineyard for Minnesota cultivars from 2010-2015. 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

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

Vermont Apple IPM: Mid-late summer apple insects and diseases

Apple maggot fly captures are increasing in some orchards. At this point, unless you know you have really low or no AMF in your orchard, I would consider applying an effective material when you next apply a fungicide or foliar nutrient. This will allow for activity and eventual wash off prior to harvest. Check the options in the New England Tree Fruit Management Guide.

Second generation codling moth are due for management in many orchards. At UVM HREC, we caught our first codling moth on May 26. Using NEWA’s codling moth model, I know that I have accumulated 1215 degree days (base 50°F) since then. Sprays against a second generation should be applied around 1260 DD after first capture. I sprayed this morning. If you’re a little further behind, you can use NEWA’s degree day tool to calculate present and estimate near-future degree days, just enter your start date (first moth capture, or use the one generated in the CM model), end date (usually today), and base (50°F). This will allow you to use the six-day forecast to plan your best-timed spray. Precision tools like this allow for better use of fewer or more selective sprays. Using NEWA, monitoring, and knowledge of my market (retail with fairly high tolerance for cosmetic blemishes but not for wormy fruit) should allow me to get away with three insecticide applications this year. That’s half as many as we used to put on when I started 25 years ago.

Today I applied the Exirel I purchased earlier in the season. I only mention this product as a cautionary note to read your labels, every time you use a product and preferable a few days before. I bought this material for use against first generation CM, but it comes in an oil-based emulsion which will cause phytotoxicity when used with captan, which was my early summer fungicide of choice. I held off applying until this spray, but of course failed to order the more compatible fungicide I plan to use for my final fruit rot and sooty blotch / flyspeck spray. So, I was all set up, material already in the tank, so I sprayed anyway but now will need to put my fungicide on separately next week. Plan ahead.

On that note, I would consider one last fungicide against sooty blotch and flyspeck, but moreso against the summer fruit rots. The latter can be worse in doughty conditions with high heat and humidity- remember last week? Captan, especially combined with Topsin or a phosohorous acid product, are good summer fungicides, but leave visible residue on fruit surfaces at harvest if not washed off. Strobilurins (FRAC group 11) are also very effective, including some of the premix materials like Merivon and Luna Sensaton. The biological resistance promoter Lifegard is reported to have some efficacy as well. I had that left over in the shed from our fire blight management this spring so applied it this morning to improve natural resistance in the plant to disease. I don’t know how well that works, but there is some evidence of efficacy. I’ll be following up with a strobilurin next week.

For organic growers, the options get slim. I have seen where sulfur and high heat can damage fruit and actually allow fruit to rot more easily. A rotation of Lifegard with biologicals like Regalia or Serenade may help reduce disease.

Fruit need calcium now, especially Honeycrisp and other large-fruited varieties, so I’m okay making another trip out there to apply that again as well.

Peru Orchard Weed Management and Soil Health Field Day Weds, July 20

Forwarding on this excellent learning opportunity from our friends across the make in New York. -TB

Peru Orchard Weed Management and Soil Health Field Day

July 20, 2022

1:00pm – 4:00pm

The Don G Orchard Block

333 Route 22B, Peru, NY

Join us in Peru on July 20th as we discuss orchard weed and soil management! Speakers will be joining us from across Cornell’s research and extension teams. Topics will include the results of our herbicide timing trials, new vision-guided technologies for orchard weed spraying, organic weed management options, soil health demonstrations, and a discussion on our statewide orchard soil health survey.

1.5 DEC credits available in categories 1A, 10, and 22

Free to attend.

Register here: https://enych.cce.cornell.edu/event_preregistration_new.php?id=1664

Vermont Apple IPM: Midsummer management

This has really been a bit of a goldilocks season, with relatively mild, or dare I say ‘normal’ temperatures, few significant weather calamities, and just enough rain to keep us from complaining too much. That generally means low tree stress, and with the reports I’m hearing from growers and the observations I’ve made around the state, it appears that we’re headed toward a decent apple crop for 2022. But there’s still work to be done.

While it has been dry, there have been enough showers that we do need to think about keeping some fungicide coverage on against the summer diseases. The first that comes to mind is the purely cosmetic sooty blotch / flyspeck complex. If you are growing apples for cider, this disease is of no concern to you, but if you are selling fresh fruit, it does need to be considered. That said, if you follow the standard recommendations for management of a fungicide applied every 10-14 days or after 1-2 inches of rain, you will likely have visible fungicide residue on the fruit at harvest, which in a PYO or direct sales situation is just as tough to explain as a few spots are. That doesn’t mean that I suggest ignoring the disease. There is a good NEWA model for planning your sprays to manage it. Dr. Dave Rosenberger gave a good synopsis of SBFS management in a 2014 issue of Scaffolds. In it, he mentions considering both this summer disease complex as well as black rot, which can be especially bad on Honeycrisp, Cortland, and Northern Spy. The take-home message is to consider keeping your fungicide coverage up at least every three weeks or after 180-200 hours of leaf wetting. Captan plus a phosphite is a good option, but for better black rot control, captan plus a DMI (e.g., Inspire Super), strobilurin (e.g., Flint), or the old standby Topsin would be a better choice.

For organic growers, sulfur remains the material of choice, although Lifegard may have some efficacy. Bitter rot is another disease of concern that is caused by a different fungus which thrives in hot conditions and is more common when fruit finish is compromised by sprays (e.g. summer oil, lime sulfur) or when trees are drought or heat stressed.

This brings up water. It is essential, especially on young or dwarf trees, to maintain adequate water to ensure good tree growth. NEWA has a good apple

irrigation tool, but a god rule of thumb is one inch of rain per week. If you receive less than that, it is good to make up the difference with irrigation. One inch of rain equals about 27,000 gallons of water. However, if using drip irrigation, you can assume that you only need to irrigate the dripline of the tree canopy, which I’ll say requires about 15,000 gallons of water per week. The actual amount needed is more complicated than that determined in my quick calculation there, and takes into account many factors- soil type; soil organic matter content; temperature, wind, and solar radiation; tree size; tree age; crop load; etc. The point is, if it’s still dry and you have the capability, consider watering your trees.

On the insect from, we’re still in a bit if a between period, where codling moth has finished its first generation activity and we’re waiting on apple maggot. Apple maggot flies have started to be trapped in some high pressure orchards, so keep on-guard and be ready to treat when an average of one fly per four unbaited traps or five flies per four baited traps per block is reached. In the meantime, if you have seen lepidopteran larvae (caterpillars) on growing terminals, you may have a population of obliquebanded leafroller which can be managed with a cheap, effective, and low-risk application of Bt insecticide. Sprays are typically timed for 360 degree days (base 43°F) from first trap capture of the ‘summer generation’. In my experience, we don’t get strong peaks in weekly monitoring for this pest, so I like to include some Bt in any sprays in June and July that don’t have another insecticide in the mix.

Every spray this time of year should contain a calcium product for optimum fruit quality, and varieties highly prone to bitter pit- Honeycrisp, Northern Spy, Cortland, William’s Pride- should get sprays of calcium even when you’re not spraying for diseases or insects. While we’re talking about nutrients, it’s time to start thinking about foliar tissue testing to assess orchard nutrition. 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) Agro One: https://dairyone.com/services/forage-laboratory-services/plant-tissue-analysis/

Samples should be collected separately per variety, per block. Each sample should contain 25-50 leaves collected from the middle section of current season’s terminal leaves- do not collect young pubescent leaves nor the oldest leaves on a shoot. Leaf samples should be washed quickly and gently in a basin of warm water with one crop of detergent, then double or triple rinsed. Wet leaves can ne loosely placed on a paper lunch bag left open in a breezy or sunny area to dry before shipping.

That should be enough for now. Please let me know if you’re seeing anything of interest in your orchards. I do have a little time left this and next month for field visits, so if you’re interested in one, let me know that, too.

-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.

VT Grape IPM: Diseases showing up in area vineyards

The main management items that should be on the minds of growers right now are disease management, groundcover management, disease management, and maybe some insect management. Canopy management probably needs to wait a little bit.

We have been seeing some symptoms of Phomopsis, a little black rot, and some downy mildew in the vineyards we have been checking in the Champlain Valley, not to mention the unsprayed vines on my deck arbor in central Vermont. The good thing about Phomopsis, assuming that you identify it correctly, is that there are no secondary infections during the growing season. Next year’s infections are caused by overwintering inoculum on canes and rachises from this year’s infections, but the disease does not continue to spread for this season. That means that Phomopsis-infected leaves may not need to be removed to prevent spread this year, but infected canes and wood needs to be removed and preferably burned before next season. Phomopsis is a greater problem issue in years with cool, wet springs. This season did start out cool, with just enough wet to cause some infections. Vineyards, especially if managed with organic practices, should have all diseased wood cut out by the beginning of vine growth. When in doubt, prune it out. Infections on rachises which occurred this past month may not be visible until veraison, so keep your eyes out.

With the relatively dry, cool weather (not counting this hot stretch we’re having this weekend) in June, black rot infection periods have been few, but if vines were not protected or high inoculum was present, we should be seeing lesions now. Black rot does have a secondary infection cycle, where conidial spores may be produced in active lesions, leading to continued infection throughout the summer. Black rot lesions are brown, often circular but with irregular margins, and may have a purplish halo at their margin. The key diagnostic is the presence of small black fruiting bodies, pycnidia, in the center of the lesion. These leaves should be regularly removed and destroyed any time you are passing through the vineyard, especially if you are using organic practices.

Downy mildew is just starting to rear its head. This disease is a little different than the others in that it’s caused by an oomycete, rather than a fungus. Consider it something like a cross between a fungus and a bacteria (I am oversimplifying, but the analogy works for me) in that it requires water to move, reproduces rapidly in warm weather, and forms lesions on leaves from which spores for the next cycle are borne. Downy mildew managemt picks up around now, as the summer heat, and especially warm rains, pop up. For organic growers, copper rotated with LifeGard may be a best option for management of this disease. For non-organic growers, captan, Revus, Ranman, and the Phosphorous acid fungicides (e.g., Phostrol, Rampart) are very effective. A great symopsis of downy mildew management is included in Dr. Katie Gold’s 2022 Grape Disease Control article (go to page 9).

Don’t ignore powdery mildew or anthracnose. The former is fairly easy to manage but easy to get away. If you see it, consider application of stylet oil or sulfur, but not both as they are a very phytotoxic mix. Same with oil and captan- keep those two at least 7-10 days apart in the vineyard.

Managing groundcover now is an important (potentially) non-chemical IPM tool to manage disease. Tall groundcover shades lower leaves and increases humidity in the canopy, which enhances the conditions for disease formation. If you do not have a clean strip (herbicide, cultivated, or mulched) under the vines, be sure to mow, including the strip between vines that the regular alley mower misses.

Some growers may be seeing grape tumid gallmaker, but for most, I don’t recommend management. For those who have it bad, Movento is a good non-organic material.

That should be enough for now.

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 Apple IPM- Apple maggot fly traps should be prepared and hung

Assuming that you have dealt with codling moth, we’re in a calm spot between insects but it is time to hang your apple maggot fly (AMF) traps. 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. Remember to rotate your insecticide chemistries to avoid resistance development in pest populations. Resistance isn’t a huge issue with apple maggot fly that has one generation per year, but codling moth and other lepidopteran pests are still about and subjecting successive generations of them to the same class of materials can induce resistance. 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. Also, if you see any fire blight, please let me know as I have colleagues at Cornell and Connecticut Agricultural Experiment Station who are looking to sequence samples to test for streptomycin resistance.

VT Apple IPM Codling moth management due any time

At the UVM Horticulture Research and Education Center, we caught our first codling moth in our pheromone traps on Thursday, May 26. Using that day as a biofix, we start accumulating degree days (base 50°), or rather let NEWA accumulate them, and plan to apply a treatment at egg hatch. Most literature references 220 DD as the beginning of egg hatch, but the NEWA model suggests treatment just a bit later at 250 DD for most materials to improve efficacy and ensure that more larvae contact treated materials or surfaces. A second application would be applied 10-14 days after that to cover the entire generation. In order to reduce the likelihood of CM evolving resistance to specific spray materials, be sure to rotate materials so that no two successive generations receive the same class of material. There are a number of materials effective against CM, compared to the old days when organophosphates and pyrethroids were the first and often only materials to come off the shelf. Heather Faubert published a nice summary of materials effective against codling moth here a couple of years ago. Avoid using ovicides (materials targeted at eggs rather than larvae) like Rimon or Esteem at this time, as those should have been applied around 100 DD for best effectiveness. For resistance management, check the IRAC code on your material and be sure to rotate codes so that no two generations see the same material. This includes applications made against other pests, i.e., if you apply a neonicotinoid (IRAC 4A) against apple maggot in a few weeks, that also counts in your resistance considerations for CM. Since many growers rely on a neonic application for summer management of apple maggot, I suggest not using one now.

However, there’s more to the story. We have been trapping CM in some orchards in northwest Vermont and have seen widely variable catch numbers. At HREC, we have only caught that one moth, which indicates a low population in a pheromone-baited trap; at another orchard, over 40 moths have been caught. Unlike for some other pests, there is no “spray when you see X caught insects” threshold for codling moth. The rule of thumb is that captures over five to ten moths in a week suggests a high population that warrants two treatments per generation. However, a low population, as observed at HREC, may be treated with a single application at around 360 DD, or sometime next week.

This tailoring of spray application to the specific life stage of the pest, based on empirical scouting and use of accurate weather and pest models, is an excellent example of how modern IPM, using a combination of scouting, weather data, accurate models, and modern pesticide chemistries are combined to dramatically reduce environmental impact of apple pest management and likely save the grower a few dollars, too. If you’re not trapping but rather rely on the default ‘first catch’ date in NEWA or a general calendar-based timing, I do not recommend a single treatment for the first generation, you should default to two. Advanced IPM requires a thorough knowledge of your orchard and pest systems, you can’t just wing it, cut your sprays, and assume that you’ll get the best effectiveness.

Other things to think about: Nitrogen fertilizers should be wrapping up in the next week or so. All sprays should include a calcium product, and on bitter pit-prone varieties, you may want to consider making specific calcium sprays every 10-14 days until harvest. Keep an eye out for fire blight- we saw our first strikes this year on inoculated trees in one of Dr. Kerik Cox’s trials at HREC. Thinning should be done now- if you need a little more in high-value varieties hand thinning is the way to go. Scab should be done for most orchards aside from the cooler upland ones, so you could take a break in the Champlain and Connecticut valleys if you’re scab-free at this point and plan on next fungicide in a couple of weeks when the summer diseases ramp up.

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.