Timing of copper spray for FB

So it almost that time here for the first, higher concentration, copper spray (I’m using Kocide 3000 and sticker this year). I understand that the ideal timing for this spray would be at the green tip stage of the buds on the trees. And it looks like most of the trees will be there later this week. Only problem is there is a rainy spell forecast for then.

So as all fruit growers I am playing tag with the weather on this. There are some nice days forecast for early this week and I could put it on then, even though it would likely be a few days early, and may get washed off somewhat by the following rains/snows. Or I can take my chances and try to find a day later which is conducive to spraying.

Any thoughts on which is the better choice, to be early and deal with wash off or take a chance on a later spray?

Normally early and respray if needed is the best bet IMO.

I would think the later spray would be more helpful against FB, but full rates of copper have a reputation for causing fruit russet on apples if sprayed too late. I know one small grower who always sprays the full rate of copper and oil around tight cluster with little russet on his varieties, but I have never sprayed later than 1/4 inch greeen. The russet may not create a problem for the back yard orchard and a little russet is a lot better than FireBlight, especially on young trees.

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When I had FB badly I was spraying at tight cluster with the full dose and never saw any significant russeting. If you use a lot of sticker you can keep the copper on through several inches of rain.

This spring I used lime-sulphur around three weeks ago; I can still catch a whiff of it in the orchard.

Thanks Scott. Can you offer any details on what “a lot of sticker” and several inches of rain quantify as.

I did put a dormant strength copper spray on a few days ago which was my last chance at a good spray day before the current bout of wet weather. A bit early for some of the trees, but wasn’t sure there would be a chance later. I did put a teaspoon/gal of Wilt-Pruf in as a sticker (which I think is the correct amt when using this as sticker but may not be a lot). So now I am just looking to see how much water we get out of these storms, and whether or not I should rush out during any breaks in the weather to renew the copper.