Now is the time that Fireblight (apple, pear, see above) and Apple Scab (apple) diseases are spreading to new, emerging growth in the nursery. Foliar (floral) applications of products for Fireblight (such as copper, Kasumin, streptomycin) should continue to reduce numbers of fireblight bacteria on floral structures (stigmas) throughout the bloom period. The floral stigmas are the main entry point for fireblight into the tree.
Fireblight is a big concern right now because the crop is in full bloom, we’ve had warm temperatures and rain and there is so much disease inoculum from last year. The Ontario Fireblight Prediction Models can be found below:
Continue to protect new growth for Apple Scab since it has been so dry up until the other day (such as Banner, Captan/Maestro, Dithane, Luna, Fontelis) Mix single site fungicides such as Luna or Fontelis with a general fungicide such as Captan or Dithane to reduce possibility of resistance.
Keep an eye out for powdery mildew because its been so hot and dry up until the other day. If you haven’t been putting on Captan/Maestro or Dithane, try mixing Nova or Fontalis or Manzate with Captan or Dithane in your next fungicide application to help manage powdery mildew on nursery crops.