I think you missed the first line of the last message where I say that
this work was done with an airblast sprayer at 100 gal/A in my organic
orchard. One must have a dedicated sprayer for organic. I can't use the
handgun that block. Don't know what the fuss about handguns is about.
Actually, I've applied many of the organic coppers with an airblast and
solo 451 mist blower and there was really no difference in performance
in control or lack of phyto.
If we “must" continue this:
Our injury results seem to follow the acute toxicity/exposure phenomenon,
whereby injury is higher when the concentration is higher not more dilute. This
is not unlike when one is exposed to a toxin in water, air, or direct contact.
In orchard trials, reducing volume and maintaining coverage requires adequate
spraying technology. i/e Not a gun.
What does your spray deposit look like in your trials?
Copper ions in large droplets (or high volume) react with leaf tissue until the
Small droplets evaporate quicker and reduce the toxicity.
This is something you can’t see if you paint the trees with a film of water
using a gun.
When you attempt to reduce volume using the same gun, all you do is apply
“less” droplets… But they are still slow drying big droplets.
So you are likely to conclude more concentrated material is more toxic… This is
not surprising, right?
But not so relevant to orchard spraying with small droplets.
Conclusions drawn from trials performed with guns using large droplets are not
always directly applicable with airblast sprayers.
it’s Happy hour time = Drinking 2 beers or one glass of wine is the same for
the alcool test, right?
But beer “rental” is shorter than for wine because that excess volume can’t
stay in your bladder so long. So for a given metabolic rate I’m betting alcohol
in your blood is higher with beer. i/e beer would get you hammered quicker than
wine. I could be wrong, but at least it’s cheaper.
Point is: concentration vs volume is not so straightforward and spray
application technology can greatly impact results.
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Kerik D. Cox, Ph.D., Associate Professor
Plant Pathology and Plant-Microbe Biology Section
School of Integrative Plant Science
221 Barton Lab
630 West North Street
Geneva, NY 14456 USA
Faculty Office: (315) 787-2401
Fruit Pathology Lab: (315) 787-2402
FAX: (315) 787-2389
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