Question
Jim,
I have 10 colorado blue spruces in my backyard and last year I noticed that one of them has needle cast disease. I live in Ontario and we have a ban on use of pesticides such as daconil or bravo. Local nursery recommended "Bordo Copper Spray" as a remedy against needle cast. What's your opinion on this? Any other suggestions?
Thanks,

Mike


Answer
If trees are infected, fallen needles should be cleaned up and discarded in a sealed plastic trash bag and sent to the dump.

Fungicides also can be used as part of a management program. Infected trees can be sprayed with bordeaux mixture 8-8-100 (8 lb hydrated lime, 8 lb copper sulfate, 100 gal water) or chlorothalonil fungicide. Fungicides should be available at local nurseries, garden supply stores, or feed stores. Fungicides provide protection against infection and prevent spread of the disease within the tree. They should be applied to the tree when the new needles are half developed and again when they are full length.

Two years of treatment usually restores moderately affected trees to full foliage. Severely affected trees may require more years of treatment.

Bordo Copper Spray is the same as above-- Tribasic Copper Sulphate -- 53% Yes it is ok to use this fungicide.