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sprayer concentrations

Posted by John Martini 
sprayer concentrations
March 01, 2019 10:46PM
This is my first posting on the forum. I am located in the front range of Colorado with a 4 1/2 acre planting of 550 trees.
(160 trees in now, the rest planting in April 1019). I have a question that I am hoping someone can answer about spraying quantities and concentrations. I had a severe strike of fire blight on my 2 year old trees last year that I am hoping to push back this year. I have decided on a late dormant to green tip spraying of copper. After much reading I believe using a "Fixed Copper" product finely ground (ie. Nordox) is the best product, not as phyto-toxic as copper sulfate or a bordeaux mixture with lime. My problem: I cannot find a formula for concentration mixture for spraying (backpack 4 gal.) small newly planted whips or very young trees. Label directions seem to be in pounds per acre, which seems to me both inapplicable to a small sprayer (backpack) and directed at immature trees. Air misting seems grossly wasteful and over dosing with my new planting (rates meant for a mature orchard). Overly concentrated would be toxic, and under would be useless and costly. Any help? Thanks, John
Re: sprayer concentrations
March 02, 2019 12:46AM
Hi John, I've run into this issue with a number of my clients. A few years ago I put together a chart of rates per gallon that has had mixed results depending on how it is used by the grower. I am happy to share this with you, but we would need to talk first so I understand the details of your operation. I will say that for tree fruit the "per acre" labeled rates are based on 300 gallons of dilute spray per acre for full grown semi-standard trees. Labels used to have "per 100 gallon" rates for TRV calculations, but there is less of that out there these days for a variety of reasons we can discuss if we talk. For example, and for example ONLY, if the rate of your product is 8 lbs/acre, that's applied in 300 gallons of water. The per gallon rate is 0.26 lbs or 4.16 oz per gallon of water. Or 16.64 oz per 4 gallon sprayer tank. I encourage growers to mix the products is a separate bucket and then pour the fully mixed materials into the sprayer tank. Don't try and mix products in the tank itself (unless you have agitation, which most backpack sprayers don't have). Hope this helps, let me know if you need more detail or help with the calculations (which is something we'd need to do off-line since I won't do this online for general consumption since everyone's situation is different).

Mike Biltonen, Know Your Roots
Zone 5b in New York
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