Bud stage on different cultivars now ranges from green tip to tight cluster. Wetting from 2 PM March 28-1 PM March 29 resulted in our first scab infection. Assuming that few orchards have had any protectant fungicide (copper, EBDC, etc.) applied before the recent rains, it is advised that a fungicide mixture including some back action on scab be applied as soon as it is suitable for spraying. Where the scab fungus has become resistant to SI fungicides (Rally, Rubigan, etc.), after-infection fungicide options include a strobilurin (Flint, Sovran) or an AP (Vangard, Scala) and these should be combined with an EBDC (mancozeb). For processing varieties, where there is less concern about fruit russet problems, there may be interest in applying copper as a protectant for fire blight and scab. We have tested the tank-mix combination of Vangard + copper and found that it is suitable to add Vangard to copper for post-infection control of scab. Be aware that copper does not give post-infection control of scab, and the Vangard + copper tank-mix will not control rusts or mildew.
Apple powdery mildew:Rusts:
Check the rust gall inoculum in your area; cedar-apple rust and quince rust spores will likely be released with the next warm rain.
