Good week for copper application in Vermont orchards

Most apple cultivars at the UVM Orchard in South Burlington were at the silver tip bud stage when I checked on Friday, with only the slightest but of green tissue showing on the earliest ones (Zestar). I call silver tip when the bud scales at the tip of fruit buds first separate, but green tissue is not yet evident when looking at the bud from the side. Bud stage criteria can be viewed here: http://orchard.uvm.edu/uvmapple/hort/99budstage/BudStageCriteria.html

What does this mean for orchard management? The window between silver tip and green tip is perfect for applying copper to suppress fire blight and to act as your first scab spray of the season. Dave Rosenberger pulled together an excellent summary of the use of early season copper for scab and fire blight management in the March 25, 2013 issue of Scaffolds. But, while early season copper can be an excellent management tool, copper materials can be phytotoxic. That is why the early season spray is made before much green tissue is exposed. If applied when buds are closed, however, then cold temperatures immediately before or after spraying are not a huge concern. In fact, I have in many years had my airblast sprayer fan shroud ice up while applying copper- not an ideal situation, but it can happen at 5 AM when the temperature is 31 F and the velocity of air coming through the shroud contributes to rapid cooling, much like a snow gun on the ski slopes. Oil, however, is a different story when it comes to applications before or after freezing weather. Delayed dormant, silver tip, and green tip are common times to apply an oil spray to help manage mites, aphids, scales, and other overwintering arthropods pests. When oil penetrates cells, it causes phtotoxicity that can affect fruit development, especially when cluster leaves which supply most of the carbohydrates to developing fruit early in the season are damaged. Oil is often applied at dilute rates, and the goal for a grower should be to fully saturate the tree as best possible. Application of oil just after or before freezing events (say 2-4 days) can cause damage, so if you have seen or are expecting freezing temperatures, put the oil away for a couple of days.

Fortunately, oil can be applied right up to tight cluster-early pink bud stages, and in fact may be more effective then. We should be out of frost risk by then (otherwise we have bigger problems than oil on fruit cluster leaves), so maybe delaying your oil application would be prudent, so long as you can fit it around Captan sprays later in the season. Oil should not be applied within 7-10 days of a Captan or Sulfur spray. For more details on spring oil applications to manage mites and other pests, including rates and spray incompatibility issues, please refer to the New England Tree Fruit Management Guide.

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.

Happy Spring, and the 29th March Message

As promised, the apple season has begun today, April 1 with….cold and snow. No, we are not at green tip yet, but I have seen tiny bits of green tissue poking out from some early cultivars and received a report from an orchard in the southern part of the state the other day that they were just around the corner.

I won’t belabor the things that growers need to think about, as a more timely message will be sent once buds start to break. But this is a reminder to start checking your trees regularly and to record bud stages- these are needed for many models in the NEWA system. You also should be tuning up your sprayers, as any day now we’ll be making the call to apply copper to reduce overwintering fire blight and prevent early season apple scab infections.

I would like to take this moment to share the UMASS March Message, which is both linked and attached. This summary coordinated by Dr. Jaime Pinero and the UMASS Fruit Team carries on the tradition of the late Ron Prokopy, who summarized the latest IPM research topics for growers just as the season was beginning.

Finally, anyone who missed the New England Winter Fruit Webinars, which included discussion on sprayer calibration, apple insect pest management, and updates to the NEWA system, can view them here: https://www.youtube.com/playlist?list=PLUL3FZJYGp3n04GfGTlQgoXoKBk7R2Xx7

-Terry

From: Jaime Pinero

We are pleased to bring you the 29th edition of the March Message!

See PDF attached – the table of contents is interactive; clicking on a section takes you to that respective page.

Google docs version:

https://bit.ly/3dhp4yc

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.

29th Annual March Message (2021) .pdf

Vineyard nutrition survey for distribution to Vermont growers

Passing this vineyard nutrition survey on from Patty Skinkis at Oregon State. They are hoping to collect this data in April. -TB

Vineyard Nutrition Survey

A multi-institutional research team involved in the HiRes Vineyard Nutrient Management Project seeks to understand current vineyard practices and the technologies that may be used for improving nutrient management practices. They invite all commercial grape growers, consultants, and vineyard management companies from the wine, table, raisin, and juice grape industries across the US to complete a survey. The survey will gather input on what, how, and why nutrient practices are used in vineyards. Make sure your state and grape sector are represented–participate today!

To complete the survey, go to https://beav.es/JRk.

If you have any questions about the survey or the research, please contact Patty Skinkis, Oregon State University, or Markus Keller, Washington State University.

Patricia A. Skinkis, PhD

Professor & Viticulture Extension Specialist

Oregon State University | Department of Horticulture

Oregon Wine Research Institute

4017 Ag & Life Sci Bldg

2750 SW Campus Way

Corvallis, OR 97331

P: 541-737-1411

Faculty website | Extension website |OWRI website