Apple scab management this week

By Terence Bradshaw

Well, so much for spring. Things sure cooled down this week, with apple trees pretty much parked between green tip and half-inch green bud stage, with a little more advancement in southern parts of the state. The primary scab ascospores that drive the whole disease cycle for the year and overwinter on the orchard leaf litter are maturing a decent pace, with about 15-18% of potential spores mature in the south, 10% in the cooler northern Champlain Valley, and only 2-5% in inland Vermont. Relatively warmer weather tomorrow should push things ahead a bit. Key take-home: Those warmer areas with any appreciable green tissue showing and a history of scab in the orchard last year are entering the accelerated phase of ascospore maturity and should be prepared to maintain protective fungicide coverage before rain periods until the ascospores are all released. That means that orchards should apply between rains this week, after 1-2 inches of rain, and when new growth emerges (say a move from 1-2 bud stages and increasing shoot leaf expansion, when that starts anyway). That means that in weather like we’re seeing now, maintaining a roughly 7-day schedule. Please use NEWA to track weather and disease infection periods to best plan your spraying events. It’s getting very muddy out there, so try to minimize your trips by applying tank-mixed fungicides including a protectant (e.g., captan, mancozeb, sulfur if organic) and a kick-back material (I recommend Vangard or Scala, still, at this time of year).

Insects are still quiet, but expect tarnished plant bug and European apple sawfly to start moving with the first warm day or two.

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.

Scouting workshop May 16; apple season is well underway

By Terence Bradshaw

At the UVM Horticulture Research and Education Center (HREC), we hit the green tip bud stage on McIntosh today. This means that, even for orchards with relatively low apple scab inoculum that carried over from last year, disease management should commence any time. Today would have been a great time to put a protectant material on ahead of the rains expected tomorrow and through the weekend. For growers who had scab last year and who are at this same or later stage of bud development who did not have a protectant applied on Monday or Tuesday this past week, plan on applying a material with some kick-back action when the rain and winds die down. Scala, and Vangard are natural options at this time, as they work better in cool weather and have relatively little effect on fruit scab so they are less useful later in the season. For those who still use or planned to use it as a spring fungicide, Syllit/Dodine is no longer registered for use in Vermont, although remaining stocks may be used up. For orchards past 1/4” green tip, it is too late to apply copper fungicides at traditional labeled rates for efficacy against apple scab without risking fruit russeting. As always, check the New England Tree Fruit Management Guide for complete recommendations (hard copy guides still available at: http://go.uvm.edu/netfmghc).

On the arthropod front, this is still a good time to apply oil for management of mites, and Esteem may be applied against San Jose (SJS) and other scale insects if they are a problem in your orchard. Notice I did not recommend Lorsban (chlorpyrifos) against SJS and other insects at this time. That’s because chlorpyrifos products are no longer registered for use in Vermont.

This is a great time to start your orchard monitoring program: keep track of phenology on all cultivars are bud emerge and develop, and start hanging traps in the orchard for weekly (at a minimum) monitoring. Insect activity is generally pretty quiet now, but tarnished plant bug will start to move as days warm up. This would be a good week to get traps up for this insect pest. We recommend four white sticky traps per block hung knee high in a visible location, often at the block edges. Traps should be checked at least weekly and treatment for TPB considered if over threshold. Thresholds are variable based on tolerance for cosmetic damage- for apples marketed wholesale, three bugs per trap before tight cluster or five before pink bud would warrant treatment; for retail and pick-your-own orchards, the recommended treatment threshold is five and eight bugs per trap, respectively, for those bud stages. TPB and other insects managed at pink are usually treated with a synthetic pyrethroid material and that is still the recommendation. In order to conserve wild pollinators, we do not recommend use of neonicotinoid insecticides before petal fall.

On the subject of scouting, we will be hosting an Orchard Scouting Field Workshop at the UVM HREC on May 16, 1-4 PM to help growers with implementing scouting programs and to discuss upcoming management strategies.

Good luck out there.

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.

2019 New England Tree Fruit Management Guide available!

By Terence Bradshaw

For as long as I’ve been in this fruit business with UVM (1995-present) and well before, the cooperating Extension fruit programs of the New England Universities have collaborated on a management guide for commercial tree fruit growers. That guide has taken numerous forms, but in 2017, we switched a on online-only platform due mainly lack of funds to prepare and print the guide every year. The online guide is still available, and should be a main resource for fruit growers: http://netreefruit.org/. That guide is formatted for both desktop and mobile devices, and will always be the most up-to-date one published.

In response to demand for a printed, hard-copy guide, we formatted the online guide into a 300-page, spiral-bound version that may be useful to keep in the truck, tractor, or spray shed. I have twenty copies available at: www.regonline.com/2019netreefruitmanagementguide. Copies are $25 postage-paid, and I plan to ship Wednesday and Friday this week. If there is demand for more copies, they may be available from UMASS or other cooperating states.

Good luck out there, at the UVM orchard, the spray season already started today.

-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.

Beginning the 2019 viticulture season

By Terence Bradshaw

After a long winter, spring is here and bud break is approaching. Plan on wrapping up pruning in the coming weeks and removing brush from the rive alleys to the burn pile (and burn it, too, to reduce overwintering insects and disease inoculum).

This is a good time to review your previous season’s spray records and to identify any gaps that may have led to disease issues. Weather in 2018 was variable across the state, with areas north of about Route 4 seeing very dry/drought conditions, and areas in the southern part of the state seeing above average rainfall. Overall, disease management was fairly easy in 2018 and disease incidence low. Don’t let that lull you into thinking that 2019 will necessarily be the same.

We have updated two disease management documents in 2017 for Vermont and area grape growers: a table of relative disease susceptibility of cold-climate cultivars and an initial IPM strategy for cold climate winegrapes. More information on general viticulture and other small fruit production can be found in the 2019 New England Small Fruit Management Guide , and the 2019 New York and Pennsylvania Pest Management Guidelines for Grapes are now available and should be used in combination with specific pesticide labels to select pesticide materials for use in your IPM program.

One pesticide spray that is often considered by growers is a late dormant application of lime sulfur (LS) which aids in inoculum reduction against many diseases, especially phomopsis and anthracnose. Growers who have had more than a passing amount of either of those diseases, especially organic growers with more limited choice of materials during the growing season may consider applying this practice, but I make that recommendation with several caveats. While LS is an organically-approved pesticide, it is one of the most acutely toxic materials I have ever used, and demands special considerations for its use. It is also a restricted-used spray material, so unlicensed applicators may not purchase or apply it. LS (active ingredient calcium polysulfide) is very caustic; spray mixtures tend to have pH around 10-11, and that characteristic is what gives it its sanitizing effect as a biocide. Contact with skin or especially eyes must be avoided, and it is pretty noxious even when smelled through a respirator. This material demands respect. While those effects will dissipate in the field after sufficient washoff and degradation by rain and other elements, I would only plan on applying after pruning is finished so not to muck around in it after application. In fact, very thorough pruning out of all dead and diseased wood is an important cultural disease control practice, and if you have a lot of such wood left in the vineyard, spraying your way around pruning it out won’t help.

LS is typically labeled for application at "15-20 gallons per acre in sufficient water for coverage" (Miller Liquid Lime Sulfur). That is a very high amount of LS, and would be difficult to apply and very costly when applied to large acreages. The key is to fully soak all woody tissues in the vineyard. This may mean aiming all nozzles at the cordons, but that would leave the trunks uncovered. Alternatively, the sprayer could be operated to cover the whole zone from the fruiting wire down, which would waste a tremendous amount of spray. The best application may come from a careful handgun application, which will take a long time and should be done with full protective gear including heavy nitrile gloves, full face shield and respirator, and Tyvek or other chemical-resistant, disposable coveralls. It is hard to say how much you would apply per acre in a directed spray, since that would be much more efficient with less wasted spray than an airblast application. My suggestion would be to apply a 10% solution (1 gallon LS to 9 gallons water) by handgun to cordons and trunks in a very thorough soaking spray. If you need to use an airblast to cover more ground, I would concentrate my nozzles toward the cordons but leave one or two directed toward the trunks, that will waste spray between vines but will allow you to cover ground much quicker. Because of the reduction in efficiency, I would calibrate to apply ten gallons of LS per acre in at least fifty gallons of water.

Remember, this stuff is caustic, stinky, and degrades just about everything it touches. It’s also quite phytotoxic- application at these rates to vines after bud break will cause leaf damage if not outright defoliation. I have used a lot of LS during the growing season in organic apple production, and don’t recommend it there unless absolutely necessary. I do not have experience using it in-season (post-bud break) on grapes, so this recommended spray must be applied during the window between pruning and bud break. The spray, if left on tractors and in sprayer plumbing, will corrode hoses, gaskets, and even stainless steel. It must be thoroughly rinsed from sprayer systems and the rinsate applied back out in the vineyard, not dumped on the ground. Some growers have applied a film of vegetable oil via backpack prayer to tractors and sprayers before an LS application to prevent it from soaking into and corroding steel and other materials on equipment. It’s that bad, and I could show you sprayer hitches, mix screens, and ceramic nozzles that have been degraded by it.

With all that said, LS is extremely effective as a preventative practice to reduce disease inoculum, and I still recommend its use in vineyards where anthracnose and/or phomopsis have gotten a bit out of control. Just be careful out there and treat it with the same (and a little more) respect that you should retreat any pesticide.”

Good luck with your vineyard activities in the coming weeks, and let’s all hope for a ‘normal’, gradual spring warm-up.

-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.

Green tip on apples expected as early as this week

By Terence Bradshaw

After a long, drawn-out winter like those from the ‘good old days’, it’s hard to believe that spring often happens pretty quickly. By that I mean that we’ll shift from winter activities when the sleeping trees provide us plenty of time and bandwidth to tend to certain tasks, but when the buds open and green tissue starts showing, we need to shift and be ready for the growing season.

I predict that it is likely we’ll see some green tissue this week if we haven’t already in some of the warmer spots. That means that scab management should begin very shortly, with a copper application recommended on virtually all orchards between the green tip and no later than the 1/4” green tip bud stage. I would plan on applying copper to any orchard that had any amount of fire blight last year and which is showing green tissue or at least solid silver tip as soon as you have a suitable spray window. If possible, I would plan on applying copper to any orchard, period, that is between silver tip and half-inch green in the next 7-10 days. There is a pile of materials out there and for all intents and purposes for this delayed dormant spray any of them are effective as long as you are applying a good full rate of copper ions. The standard dry materials like Champ, C-O-C-S, Cuprofix, Kocide, etc. will give you the best bang for the buck here, and I would apply the full label rate for any of them and thoroughly spray the whole orchard. The only caveat I offer is if phenology advances rapidly before you can get out there and the trees are at 1/2” green tip, in that case, I would apply a low to middle rate. After 1/2” green tip, unless you don’t care about fruit finish (e.g., cider fruit), I would avoid copper.

This isn’t a bad time to get oil on, either, but the rate should be 2% by volume and coverage absolutely thorough to soak overwintering mite eggs, scale, and aphids. If time is of the essence, focus on copper first, especially in orchards south of the rain line that seemed to set up between Addison and Orange/Windsor counties last year which had a fair amount of scab going into the winter.

Speaking of which, there is still time to do some sanitation in the orchard by flail mowing leaves and fine brush, and/or applying a coarse urea spray (44 lb feed grade urea in 100 gal water applied per acre, directed at the leaf litter).to speed decomposition and reduce apple scab inoculum.

Keep an eye on NEWA regularly as we enter into the 2019 season. Up-to-date spray tables may be found in the New England Tree Fruit Management Guide available online at netreefruit.org and shortly in hard copy format.

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.

Slightly late, but the return of the UMASS March Message

By Terence Bradshaw

The late Dr. Ron Prokopy at UMASS was instrumental in pulling together the “March Message”, an pre-season update on IPM and other topics for tree fruit growers. Dr. Jaime Pinero, the ‘new’ UMASS Extension Entomologist, has revived this valuable tool, which I have attached here.

Key take-homes:

· Orchard sanitation this spring (especially critical for those who had scab issues last year)

· Disease management (rots, Marssonina)

· Insect management

· Invasive species status

· Plant growth regulators

· Pesticide updates

· Decision support systems

I also want to announce the pending publication of a print version of the New England Tree Fruit Management Guide. This has not been offered in print for several years. The printed guide will be a reformatted version of the material available online at www.netreefruit.org. I’ll post a notice when it is available to order. Copies will be $25 each.

Best,

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.

27th Annual March Message (2019) 2.pdf