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UVM Fruit Blog

Petal fall and then some (sometimes quite a bit more)…

Posted: June 14th, 2019 by fruit

By Terence Bradshaw

Orchards in the highest elevation and coolest areas are at or just past petal fall, so all the advice I’ve had for other growers applies there as well now. All orchards should have started or, more likely, completed chemical thinning by now. Fabulous thinning weather occurred last week and those who applied the usual materials should see the effects by now. If a little more ‘nudge’ is needed to break up clusters, carbaryl , 6-BA 9 (Maxcel, etc.), and NAA (Refine, etc.) will still work so long as the fruit you’re thinning are under 15 mm diameter. If you have a lot of larger fruit, up to 20 mm, then Ethephon + carbaryl can help in a pinch, but be careful, as that mixture is relatively unpredictable. Wes Autio and Win Cowgill have a factsheet on such rescue thinning for more information.

Regular readers may have noted that I (almost) took a week off from updates- I also took a week off from spraying. Where petal fall insecticides were applied against plum curculio (PC) and European apple sawfly, you’re probably good until another is needed for PC due to rain washoff or codling moth rears its head. As for the former, PC is only ‘programmed’ to lay eggs and cause fruit damage for about 308 degree days (base 50) after McIntosh petal fall, and we’re only about 1/3 there at the UVM Hort Farm. It would be wise to check for PC damage to fruitlets and consider reapplication at the first sign of fresh damage.

Figure 1Plum curculio damage on a developing fruitlet. This damage is about a week old, note the dried surface and lack of sap. Fresh stings after an insecticide has been applied indicate potential need to reapply.

As for the latter pest, codling moth have now been trapped in most scouted orchards in the state. To best manage the first generation of this pest, calculate degree days (base 50°F) from the date of first capture in pheromone traps. Most materials should be applied at 200 degree days after catch, which should be in the next week or so. Cornell entomologist Dr. Art Agnello offers the following specific recommendations for CM management in the latest Scaffolds newsletter: “The best products for controlling both CM and OFM in apples and stone fruits are those in IRAC Group 28 (containing a diamide; i.e., Altacor, Exirel, Minecto Pro, Voliam Flexi or Besiege) or IRAC Group 5 (mainly spinetoram, Delegate; spinosad, formulated as Entrust, is an organically approved option). Two applications from either of these groups on a 10–14-day interval would be recommended starting at 220 DD50 from biofix; we’re already beyond this point in Highland and Geneva, but sites in WNY range from 81-247 DD50, depending on proximity to the lake (refer to “Model Building” numbers in this issue). Products with insect growth regulator activity, such as Rimon, Intrepid or Esteem, would also be suitable options this week in apple sites at the lower end of these values. Other products with activity against internal leps include the neonic Assail, the biological Grandevo (also organically approved) and, in orchards where resistance has not developed to the newer pyrethroids, also Baythroid, Danitol, Endigo, and Leverage. Most older broad-spectrum materials like Imidan, Lannate, and the older pyrethroids, which were formerly more effective, are generally not as good choices because of insecticide resistance issues…Now would also be an appropriate time for an application of a granulosis virus product in pome and stone fruits such as Cyd-X, Madex, Virosoft CP4 or Carpovirusine (apples and pears only), in addition to the larvicides discussed above. These are biological insecticides, which must be ingested to initiate the infection, after which the virus replicates inside the larva until it is killed; this releases more virus particles into the orchard. This is a very useful approach for long-term population reduction, particularly when used in at least 2 applications per generation. Madex, and now Virosoft CP4 (see “Chem News” in this issue) contain an isolate that is also effective against OFM.”

As for diseases, all sites should be done with primary apple scab season. That doesn’t mean that scab management is done, just that there are no overwintering spores left in leaf litter. If you have NO scab, you’re done managing this disease for the year. However, I suspect that many orchards missed an infection period or had spotty coverage, and that there is a good bit of scab out there. If you have scab, plan on maintaining some level of preventative fungicide (Captan is about all you have, sulfur if organic) for the next month or so until fruit and foliage become resistant. Do not use single-site fungicides like DMIs, strobilurins, or SDHIs (FRAC codes 3,7, 9,11) on active lesions to reduce development of fungicide resistance.

There have been some reports of fire blight showing up from the marginal infection periods that occurred May 20, 23, or 26. Keep your eyes out, especially in blocks that have had a history of the disease or on susceptible cultivars like Gala and Paulared, and cut strikes out as you see them.

If using nitrogen fertilizers in your orchard, plan on wrapping up applications in the next week or two to give trees time to harden off for winter. Potassium fertilizers can go on any time 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, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.

Expect insect activity to pick up later this week

Posted: June 5th, 2019 by fruit

By Terence Bradshaw

Finally, it looks like we’ll be entering an extended stretch of warm, sunny weather starting Thursday and especially Friday and lasting through the weekend. In South Burlington, we’re expecting temperatures just near 80°F by Sunday. That is great weather to drive plum curculio and European apple sawfly activity, so I suggest treating against those pests Tomorrow or Friday. I’ll be going out Friday morning when the wind is looking more favorable for spray application. But remember, if you’re one of those high elevation sites with petals and bees still present, you need to wait.

All 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, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.

Orchard management at petal fall (and then some)

Posted: June 2nd, 2019 by fruit

By Terence Bradshaw

This week I’ll just say, “more of the same…” Apple scab primary ascospore season is done or nearly done in Vermont orchards. Check carefully for apple scab in your orchards before stopping fungicide coverage. Lesions can take two weeks to appear, so you may not see the latest infections for a bit. By now, growers who have been using more than three pounds per acre of mancozeb should put that away for the season, captan will be the protectant fungicide of choice. Sulfur should be the standard in organic orchards, although lime sulfur may be appropriate, especially if there are active lesions that need to be burned out and you want some thinning activity. Remember, lime sulfur is extremely caustic and corrosive to metal, to take care of yourself and your equipment if you use it.

Keep an eye out for fire blight strikes as you walk your orchards. We were generally on the ‘no conditions for infection’ side of the line in most orchards, but there is a chance that some got through, especially in warmer sites with a history of the disease where streptomycin was not applied. Prune out strikes as you find them.

Insects: still quiet. Codling moth has shown up in some sites, which means a targeted application of an effective product 250 degree days (base 50 °F) after the biofix of the first date caught in a pheromone trap. In the meantime, where you have 100% petal fall and no bees in the orchard, an insecticide application targeted at plum curculio and (if present) European apple sawfly may be warranted. Dogwood borer are rearing their heads more and more. If you have them (check burr knots on trunks, especially young trees on M9 or M26 rootstock), consider a coarse, soaking trunk spray. Best bet now is probably Assail; the old standby Lorsban (chlorpyrifos) is no longer registered for use in Vermont, and for good reason. Organic growers may consider Pyganic, and probably several applications.

Thinning: weather isn’t looking very good for 6-BA thinners like Maxcel until later this week. If planning to use those materials on smaller-fruited cultivars like Empire and Fuji, wait a bit. NAA thinners should be effective, but plan on using higher rates given the cool weather. Keep an eye on developing fruit following thinner applications, fruit will be susceptible to hormone sprays up to 17 mm diameter, after which we need to take more drastic and unreliable measures.

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.

Grape disease management and shoot thinning

Posted: June 2nd, 2019 by fruit

By Terence Bradshaw

I’m probably a tad late on getting this out for some growers. The growing season continues to be cool and wet, and grapevines at the UVM Horticulture Research & Education Center are showing about four to five inches of shoot growth. We are beginning to enter a critical time for disease management. Growers should consider applying a protective fungicide soon that has activity against phomopsis in particular, although anthracnose and, to a lesser degree, black rot may be active, especially in high inoculum vineyards. The primary disease of concern at this point is phomopsis, as rachis infection at this point in the season is may cause significant fruit loss at harvest. Anthracnose may also be active at this point. Most growers would do best to cover early this week with a contact fungicide like mancozeb or captan.

Organic growers are in for a bit more work. The standard fungicides, copper and sulfur, have only fair efficacy against this disease at best, and in a couple of weeks when black rot becomes the next disease of concern, those materials will have even less efficacy against that disease. The first line of defense in an organic vineyard is a strict sanitation program. This includes removing all mummies still in the canopy (not dropping on the ground, but actually removing them from the vineyard) as well as any obviously diseased wood. Phomopsis and anthracnose both overwinter largely on infected wood in the canopy, and removing this wood during dormant pruning or now is essential to reducing disease pressure. Stubs left at the ends of spurs should now be removed since you can see where this year’s shoot growth will resume (at the developing shoot)- these stubs will die and may become infected with phomopsis this season (or were last season) .

Removing stubs at end of retained spurs.

It is worth noting that both copper and sulfur (including lime sulfur) can cause phytotoxicity on certain cultivars. Dr. Patty McManus summarized her research on copper and sulfur sensitivity in cold-hardy grapes in the 2/8/16 Northern Grapes newsletter, and I’ll summarize it to say that Brianna should receive no copper; and Frontenac (all types), LaCrescent, Leon Millot, Marechal Foch, Marquette, and St. Croix should receive no more than 2-3 copper sprays per season. Save those for later when black rot and downy mildew become bigger concerns. Sulfur sensitivity was observed on several cultivars, and its use (including lime sulfur) is discouraged on Foch, Millot, Brianna, and Louise Swenson; with limited (2-3) applications suggested on LaCrescent and St. Croix.

So, if you have removed all diseased wood and are ready to cover your vineyard for protection against phomopsis and anthracnose, the best choices is likely lime sulfur applied at two quarts per acre in sufficient water (25-30 gallons should do it) to wet the canopy. Lime sulfur is hot stuff: caustic, corrosive, and noxious. Use appropriate personal protective equipment and spray in cooler weather to reduce phytotoxicity. Powdered sulfur may also be a good choice, I would suggest 3-5 pounds per acre at this stage.

Organic growers should absolutely begin application of something at this stage in combination with keeping up sanitation of all dead or infected wood , rachises, and other grapevine debris- sulfur, one of the bicarbonate materials (e.g., Armicarb, Kaligreen, etc.), or a biofungicide like Serenade, Sonata, Regalia, or Double Nickel may be used, although there is little good efficacy data on that last class of materials.

I mentioned sanitation- now is a good time to get out and clean up the ‘nubs’ left at the ends of spurs after pruning that will die out and serve as reservoirs for phomopsis and other diseases. While you’re at it, this is an especially good time to thin shoots. Cold hardy grapes trained to a high-wire trellis and in good health can support about six shoots per foot of canopy; select the best developing shoots and break off the others now while they are easily breakable with your fingers. Maria Smith and Dr. Michela Centinari at Penn State recently wrote a good summary of shoot thinning available here. I suggest reading it on the deck this holiday weekend with a nice glass of wine, and getting out in the vineyard next week to set this year’s crop on the right track.

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.

Petal fall approaching for many; Bloom for others

Posted: May 27th, 2019 by fruit

By Terence Bradshaw

As has been the general case this year with the drawn-out, cool weather, we have bloom (and p-bloom) bud stages all over the place depending on elevation, proximity to the lake, cultivar, and latitude. For growers in upland sites just entering bloom, see my posts from the past couple of weeks that have been aimed at bloom-time management. Remember, no insecticides; mow flowering weeds in the groundcover to make your trees more attractive to bees; and watch for fire blight. Keeping an eye on that very weather-specific disease can be more difficult in upland areas where NEWA stations are less prevalent. However, a look at stations in East Dorset, East Montpelier, Morrisville, and Berlin (‘Montpelier’ airport) shows EIP (potential bacterial population) below infective level all week, although a warmer-than-expected Wednesday or Thursday may change that. Overall, I wouldn’t be too concerned about fire blight for those sites, but would keep an eye on things.

Growers in warmer areas, however, may need to be concerned. Shoreham was flagged as having had an infection event yesterday, and an application of streptomycin today (like, now) to open blossoms may be prudent, especially on susceptible cultivars. Remember that blossoms are pretty much done as far as disease susceptibility is concerned once the petals fall, or 80 degree days (base 40) after they open, or 3-5 days given the weather we’ve been having.

Apple scab is the main disease to stay concerned about statewide. This is proving to be a challenging year for the disease, with infection periods occurring every week since bud break and reports of numerous tractors stuck while spraying. The good news is that we’re on the tail end of the primary apple scab infection season when the overwintering spores resulting from last year’s infections on leaf litter are close to expended. If you manage to keep covered with fungicides during that window and all infections are prevented, then apple scab season ends when those spores are gone. However, any infection in the tree canopy will lead to development and release of conidial spores which creates a secondary phase of the disease. My point is, keep protected until you know that you are scab-free and the spores are all expended. Some stations (Bennington, Cornwall, Shoreham) called for the end of primary season last Thursday, many more are indication that we’re within 1-2% of the spore load left. For those orchards, I recommend maintaining a good coat of fungicide through this week, and likely next. Depending on the material you choose, this application will cover you against powdery mildew, rust, and moldy core which can be a problem in cool, wet bloom periods. In 7-10 days, get out and do a thorough assessment of foliage for scab lesions. Pick the worst-case spots- tops of trees, that corner of the orchard where you turn and can’t get good coverage on that one last tree, the shady spot where the trees stay wet longer. Only after you know you’re clean can you let your guard down.

Speaking of letting your guard down, many of us did on the insect front going into bloom because trap counts were low for most insects across the state. We’re now seeing high numbers of European apple sawfly on traps in many orchards, and I expect a petal fall spray will be warranted against them. Pay attention when making this spray- petal fall means that all blossoms are gone, your migratory bees are pulled out, and flowering weeds attractive to wild pollinators are mowed. There are a number of materials that are effective against EAS, and all are toxic to bees to one degree or another. For organic growers, now is the time to get a good, solid coat of Surround kaolin clay onto your trees to deter plum curculio. I always preferred to apply this base layer in two coats, one at ~50 lb Surround per acre followed by another 25 lb per acre to get a good build up going into petal fall and the beginning of the real incest management season.

Thinning. This is always tricky to give advice on, and the variable conditions across the state make the job even harder. Many orchards have a larger-than-normal potential crop, and pollination should have been sufficient given the handful of good ‘bee days’ where conditions were right for bee flight and fertilization. This is a good year to consider multiple ‘light coats’ of thinners. NAA + carbaryl are a typical mix to apply at petal fall on many cultivars. For smaller-fruited cultivars, 6-BA thinners may be used instead of NAA to increase cell division and final fruit size, but they need warm sunny weather to work best. NEWA has a good model (two of them, actually) for helping to determine the potential effectiveness of thinner applications based on weather before, during, and after application.

This is the most critical time to keep your eyes open out in the orchard. Stay alert for signs of fire blight and apple scab. Check traps daily for codling moths to help determine the biofix date that you’ll use for subsequent management decisions. Keep an eye on fruit clusters for signs of thinner activity (yellowing stems, sepals that don’t close up). Get you nitrogen and other nutrients on, multiple lighter coats are better in rainy years than one big one to minimize leaching and runoff. Watch for and enjoy the sunshine. This weather can’t last forever.

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.

Early vineyard management

Posted: May 21st, 2019 by fruit

By Terence Bradshaw

Buds have broken in most Vermont vineyards and many vines are at 1-3” shoot growth. 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 earlier, especially if inoculum reduction through thorough removal of diseased wood and mummy berries and/or dormant application of lime sulfur was not performed. I still recommend our fact sheet, An Initial Integrated Pest Management (IPM) Strategy for New Cold Climate Winegrape Growers 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 England Small Fruit Management Guide (on-line and hard copy versions) and/or 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 past few days may have increased emergence of grape flea beetle or cutworms. Grapes are susceptible through about the one inch shoot growth stage, so vines will eventually outgrow the threat. However, cooler temperatures this week may hold the vines at this susceptible stage long enough for damage to increase to unacceptable levels. 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 weekend, don’t worry about this pest. More information may be found here.

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.

After buds emerge you can begin to thin shoots down to the desired number, usually 3-5 per foot of canopy, but I advise against shoot thinning quite yet. There is still plenty of time for frost, flea beetle, wind, or other damage. Wait until after Memorial Day or early June to thin out your canopy, but not too long.

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.

Fire blight pt II

Posted: May 18th, 2019 by fruit

Fire blight pt II

Posted: May 17th, 2019 by fruit

By Terence Bradshaw

Sometimes you need to check the latest weather before hitting ‘send’…

After I just sent that last missive, I double-checked conditions in western Vermont, specifically Shoreham and Bennington, and the weather prediction is indeed for warmer weather than when I last looked. NEWA is now calling for “Infection” on Monday for those two sites, but the EIP is just barely over 100 (107 and 103, respectively) and drops down the next day as cooler weather moves in. I’m going to stick with my old gut response to not worry about fire blight, with a slight caveat. If you have a history of the disease, have especially susceptible plantings (Gala, Fuji, some cider varieties), are in bloom on Monday, and things warm up over the weekend, consider applying streptomycin on Monday or Tuesday, within 24 hours of infection. Keep an eye on NEWA for further details.

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.

Apple scab, what would we do without you?

Posted: May 17th, 2019 by fruit

By Terence Bradshaw

Here’s a quick note to remind everyone that we’re in the middle of an extended wetting and apple scab infection period that is likely to peak on Monday. Every orchard in the state still has mature ascospores in the leaf litter from last year, so stay protected. We’re also still in rust season, so it’s not a bad idea to make sure your fungicide products have some efficacy against that disease. If you’ve had more than an inch or so of rain between spray events, and especially if more than 1.5-2”, you should really think about applying a DMI (FRAC 3, e.g., Indar, Rally, etc., high efficacy against rust), strobilurin (FRAC 11, e.g., Flint high efficacy against rust), or SDHI (FRAC 7 e.g., Merivon, moderate efficacy against rust) with your protectant material (captan is good, no rust efficacy; or mancozeb, good rust efficacy but only allowed four applications through bloom at 6 lb/acre rate so you may have used that up). Remember to rotate between FRAC codes to avoid resistance development, and the mix products like Inspire Super (3+9) or Luna Tranquility (7+9) or Sensation (7+11) count as both when planning your rotations. That is, if you use two back-to-back application of Luna Sensation (7+11), your next spray including one of the single-site products should be a DMI (3) or anilinopyrimidine (9, which are less effective as temperatures warm) material. More information on fungicide resistance management is available in the New England Tree Fruit Management Guide.

For organic growers, the standard is still sulfur, and possibly judicious use of lime sulfur if you’ve missed some coverage and need some protection to reach backwards. Remember though, lime sulfur is nasty stuff, so use judiciously and take all necessary precautions. For rust, sulfur isn’t very effective. I have heard reports that Regalia, a biological fungicide, has some efficacy against rust so this is as good a year as any to try it out.

One great bit of news on the disease front- fire blight should be a complete non-issue this year. That could change for late-blooming cultivars or if active cankers are leading to shoot blight later on, but for now, it’s just too cool for any activity from the bacteria that causes the disease. NEWA’s Cougarblight model shows “high” risk for Sunday and Monday, but that’s to be taken with a grain of salt. There are four conditions necessary for blossom blight to occur: open blossoms (check); wetting (check); sufficient heat, measured in degree hours, over 60°F during the infection event (maybe); and sufficient heat leading up to infection to allow the bacterial population to increase to a level high enough to cause disease (nope). Using NEWA’s fire blight model, keep an eye on the “Infection Potential EIP Value”, that should reach 100 before you need to be concerned about blossom blight. Cougarblight assumes “High” risk if three of the four conditions are met, even if the fourth necessary condition (EIP in this case) is not likely to be met. We would need temperatures a good ten degrees higher than predicted tomorrow through Monday to move that EIP into any range to worry about.

Figure 1 NEWA fire blight model for Putney, VT. Most sites in the state will have even lower risk than this. Take-home: don’t worry about blossom blight now.

Orchards are in or entering bloom. That means a few things. First, get those blossoms and the ovules they’re attached to in good shape by applying a foliar fertilizer if you haven’t yet, I’ copying my own text from 5/5 here for that: Rates are dependent on the products used, and are intended to boost blossom vigor as the trees enter the stressful bloom period Dr. Wes Autio’s (UMASS) recommendations for Prebloom Nutrient Applications for Apple Trees: 3 lbs/100 gallons (dilute equivalent) urea; 1 lb/100 gallon Solubor (or equivalent); and label rates of zinc chelate. Ground-applied or fertigated fertilizers can also start to go on any time now. Organic growers may want to apply fish and/or seaweed products at this time.

Remember, bloom means bees, bees pollinate, and pollination = ovule fertilization = fruit. Protect them, both managed and on-managed (wild). That means avoid spraying anything, if you can, during bloom. Even some fungicides, DMIs in particular, have shown adverse effects on bees when applied to blooming orchard crops. Mow your dandelions to both force bees into the trees to work and to reduce their (the bees’) presence after bloom when you think about applying a petal fall insecticide. And for heaven’s sake, do not apply insecticides when there are flowers (apple blossoms or dandelions) in the orchard. The exception to that is Bt or other lepidopteran-specific products. On to insects…

Insect activity is really slow this season. The only insect captures of note have been European apple sawflies. If you’re at pink (i.e., ZERO blooms open) and have a population above threshold (five per white sticky trap, average), this may be a warranted application. But, application of insecticides so close to bloom is still a dangerous endeavor. Many wild bees are moving now, and since they often fly in cooler, wetter, windier conditions than managed honeybees, they may be especially important this year given the crappy weather we’re having. If you can hold off until post-bloom, I strongly recommend it.

Get your codling moth and obliquebanded leafroller traps up ASAP and check daily to set the biofix you’ll use to manage the larvae in a few weeks.

On a final note, herbicides, if used, can be applied any time, and application to weeds 6” or shorter is always more effective than waiting. Be careful with contact to trees, including mature bark, with glyphosate or glufosinate. Extra time spent is well-worth it to avoid trunk damage.

Are we having fun yet?

-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, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.

Apple scab infection period now… (May 13)

Posted: May 13th, 2019 by fruit

By Terence Bradshaw

This is a very brief message to Vermont apple growers that we are in a dry and relatively windless slot between significant wetting events and it would be wise to make sure that your fungicide coverage is maintained. I wouldn’t worry about insects now, unless you are treating for scale, but a quick reapplication of anything that may have washed off if you sprayed prior to Friday is called for. I’m heading out right 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, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.

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