What product teminates blue on a blue spruce?

I'm a bit rusty on my pesticide knowledge these days. I used to have a consultants license, but I've bailed out of applying pesticides for at least 10 years.

But I was curious about something.

I recall my pesticides instruction mentioning a pesticide that would eliminated or hinder the blue color on a blue colorado spruce for a period of time.

Like my Blue Ice Arizona cypress, the blue can rub off the needle of a blue spruce, leaving the green foliage.

Apparently, one or more pesiticides interfere with this coating, which I vaguely recall as being referred to as "bloom" (correct me).

For some reason, an "oil" or insecticide seems to come to mind, but I don't remember for certain.

Anybody out there that's up to date on this?

Thanks.

 

Anything oil-based will dissolve the blue wax coating and leave the needles green. Even a spraying with cooking oil would do it. The colour change is irreversible; the greened-up needles will not turn blue again, the only time it will turn blue again is with new growth the following spring. Oils may or may not also harm the tree as well.

 

Thank-you for the info.

By the way, I wasn't hoping to terminate any blue on spruces - just to refresh on some information.

Hope nobody became surprised by the post title.