May 5, 2014
All orchards in the state experienced extended apple scab infection periods from April 30 through today. Depending on your site, you may have had a break in the infection period from May 1-2, but for all intents and purposes, this was one that you needed to be covered for. If coverage was questionable, application of a postinfection material as soon as possible (today or tomorrow) would be prudent. Please keep Dave Rosenberger’s “Fungicide Considerations for Tree Fruits in 2014” article in the March 25 Issue of Scaffolds handy for easy reference. It looks like we have a dry period this week from Tuesday 5/6 through Thursday 5/8, which should give everyone a chance to get their next fungicide application on before rains begin again over the weekend.
Many orchards are at tight cluster now, and pink will not be far behind. This is a good time to apply a fungicide effective against powdery mildew, such as an SI or sulfur in combination with mancozeb or captan as a protectant. Prebloom is also a good time to consider foliar applications of nitrogen (urea at 3 lbs/100 gallons dilute), zinc (zinc-containing EBDC fungicides or EDTA zinc chelate at label rate), and boron (1 lb/100 gallons dilute) that are especially helpful in strengthening winter-weakened fruit buds. Dr. Wes Autio from UMass published a good fact sheet on prebloom foliar nutrition here.
I saw my first Tarnished Plant Bug in a fruit bud this morning. While our trap captures are below treatment threshold at this time, it is good to start thinking about your insect management program. If this cool spring continues to play out, an application of an insecticide at pink may be prudent because extended bloom may prevent application of an insecticide for quite a spell until petal fall.
Terence Bradshaw, UVM Tree Fruit and Viticulture Specialist
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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.