Favorable spray conditions May 17

May 17, 2014

For growers who need to cover their orchards for the apple scab or fire blight infection periods that occurred during this last round of rain, today looks like a good spray day with generally low wind speeds (as always check your conditions on your farm before listening to me). Winds look to be shifting from westerly to northerly over the course of the day, and dying down an bit through the evening and overnight.

A few tips:

  1. If you have open blossoms, put the insecticide away. This past week was the time for a pink insecticide, give the bees a chance to make your fruit for you.
  2. If you had fire blight in your orchard in the past couple of years and you had open blossoms yesterday, a streptomycin application would be prudent. Strep should be applied with a spreader like Regulaid to aid penetration into blossoms. If you would like to reduce your strep use, this is the important spray to apply it in; you can follow up with one of the biological materials in a couple of days when more blossoms open (and the threat has decreased).
  3. I would avoid captan right now, based mainly on its potential for leaf burn and fruit russetting. There also is some evidence that captan may reduce pollen germination. This is a good time to pull out one of the SI, QOI, or SDHI fungicides, combined with an EBDC protectant. If you don’t understand that alphabet soup by now, please refer to your 2014 New England Tree Fruit Management Guide.\

Terence Bradshaw, UVM Tree Fruit and Viticulture Specialist

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 newsletter 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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