copper spray

[charline]

http://www.agr.gc.ca/fra/science-et-...=1198101468695

they explain the treatment but I will ask someone who may be knows how it is done here.

[cwavec]

Charline,

Thank you again. I have also found some literature and found out that this fungus
is unknown anywhere in Europe. So it is on the OEPP A1 quarantine list to keep it
out. Unlikely then that anyone you know will recognize it. But some of the papers
I have found, starting with the one you sent, have some pretty good info. By the
time I can put together all the pieces, it might be encouraging enough to try again.

P.S. - I have more to say about copper sprays - surfactants, fixed copper,
phytotoxicity, etc. but no energy to do it right now. Later

[PureHarvest]

I started using this stuff this year and really like it.
No spreader sticker used.
It's made it in Europe.
Also OMRI approved for organic production if that is important for you.

http://www.7springsfarm.com/nordox-75-wg-12-5-lb/

[brownrexx]

Excess spray falls on the soil and it does not break down in the soil so it can become toxic in high levels. That is why you should limit the amount that you spray.

I use a biologic product called Actinovate to prevent blights.

[Lindalana]

I can only answer for my area. After doing my soil test I know levels of copper in the soil. I like to use no more than 6 copper treatments per season, preferably less. Major problems for me early blight and Septoria.
I use Soap Shield with spreader sticker.
Mostly I prefer use biological treatments. Actinovate, Microbelife products, Aerated compost tea are my preferred choices currently. I also noted that using myco during planting times does help great deal with early blight.

[cwavec]

I can only answer for my area.

I like that approach. After all it's really all that anyone should try to do. Notice
though, that Charline, who started this thread with a question, is in France
and is using a spray mix that rarely is used in the US, at least for tomatoes.
That's OK because it seems to be what is primarily available there.

But that brings me to your mention of "Soap-Shield" which is, of course, the
copper soap that I have been talking about. Copper Octanoate 10% concentrate.
On the other hand, copper is copper and behaves the same wherever you are,
the differences being in local conditions such as weather, soil, etc. and the
adaptations that have to be made to meet those conditions.

I don't know the level of copper in my soil but have some confidence that it is
pretty low because I am the only one who has used that garden space. Before me
it was in forest and I haven't used "much" copper at all.

I mentioned earlier that I don't care for the bouillie bordelaise and the reason
is what Lindalana has to say about copper levels. Bouillie bordelaise has a lot
and in a form that will easily accumulate in the soil. Whereas, copper soap only
has 1.8% copper concentration. That's extremely low compared to some of the
other products that have been mentioned. It seems to provide enough free
copper ions though and, with a higher dose than I now use, I encountered
phytotoxic effects so I know I don't want any more.

I need to do more than 6 applications in a growing season or else I get foliar
disease problems but I have found that I can compensate for that by reducing
the dose. 1/4 oz. (8 ml) per gallon (4L) is way below the manufacturer's
recommendation. The spreader-sticker also makes a very big difference in
the efficiency of the copper.

My main difficulty also is Early Blight (whenever we don't have a spread of
Late Blight). Interestingly, even with that low dose I so far have no (yes, I
said no) signs of Early Blight. Perhaps it's a bit early to arrive at a conclusion
but so far it's looking good. In past year I would have seen the first signs of
infection by now.

[berryman]

Cwavec, thanks so much for your knowledge and attention to detail here. Because I garden in the second driest state in the union, I don't have these foliage problems and have never in 35 years had to use a copper spray.
Isn't this bb spray the same one used on wine grapes, and if so I can only imagine the accumulation of copper in the soils after several hundred years of spraying. Perhaps Charline herself knows the answer to this question as well.

[cwavec]

Berryman,

Thanks for the thanks. Only I wish I were knowledgeable but really am not. It's
what I've been able to accumulate painstakingly from mostly extension bulletins,
etc. on the internet and some very disappointing experiences. There is much
deeper and comprehensive knowledge behind all of it and I wish I were privy to
more of it.

Yes, as far as I know this spray is the same thing, called in English Bordeaux Mix
although there is another one, bouillie polysulfure, a lime sulfur mix that is
possibly more famous but maybe not used as widely anymore. For a day or so
I've been looking into using it for something else. It looks like a real mess to make.

Charline probably knows this and more. She did start this thread with the very
valid question of how do we use this stuff. Just look at the manufacturer advice
to see how vague and unhelpful it often is.

By the way, I wonder if France has dried up yet - maybe just a little?

[cwavec]

I would like to say more about a paper from Cornell University that I linked to early
in the thread. Here is the link again:

http://cvp.cce.cornell.edu/submission.php?id=140

There are aspects of this publication that bother me quite a bit so lets take this thing
apart and see what we find.

First off, at the bottom of the text is a line that identifies the "sources" of the
information as T. A. Zitter and David Rosenberger. OK, so they just "sourced" it.
They are both highly respected professors of plant pathology so why couldn't they
just write the darn thing. My point being that I think whoever did write it has
distorted and obscured some vital information.

The first couple of lines are OK - just background.

In the next line we get to anticipate a discussion of the "mode of action of copper"
but that doesn't follow until after a long foray into the different copper formulations,
how they sit on the leaves and get released gradually. OK, we'll get back to that
but first lets see about MOA.

Every fungicide, pesticide, etc. has a short description of its MOA or "mode of action"
These are classified and tabulated so that users can get an idea what choices they
have, select and coordinate among the different materials and possibly expect
what the effects might be, including unwanted or damaging effects. Deep into
this second paragraph we get this, "Copper ions denature proteins, thereby destroying
enzymes that are critical for cell functioning". Well then, there it is, the MOA. The
statement seems factual enough though rather vague and I think not very
meaningful for anyone who might actually use this paper. I'm not a
biologist or a professor and don't want to tangle with anyone who is but I've
looked around and found other descriptions that appear far more satisfying.
Be that as it may, what we have here seems harmless enough, so lets just
accept it and move on.

"Copper ions denature proteins". Aha! So what we want is copper ions. In other
words, what we might call "free radicals" in another context. Bad guys that do
nasty stuff, only here we like them because they are doing the nasty by
denaturing the proteins of somebody else (the fungi) and not us.

Lets step back a bit. We want copper ions. We want to get them from our spray
material and we want them to be where they will do some good. We want them
to "persist on plant surfaces after the spray dries". You can go back now and read
the earlier part of this second paragraph for a list of the different kinds of stuff
and deduce that from any one of these materials we want plenty of copper ions
but not too many because they would then be phytotoxic or poisonous to the
plant too.

We get served the idea that most of the time we are applying "fixed copper". Well
then, what is that and we find out that when copper is fixed it is put into a form
that is not as easy to dissolve in water. But wait, what about that list of spray
materials. How "fixed" or insoluble is each one of these? Don't they vary some?
And here is where I begin to quarrel (or quibble) with the good professors or with
their factotum or sycophant (whatever). At least one of these materials, copper
oxide, is virtually insoluble in pure water and relies on the slight acidity of rainwater
to release a few ions. That's the Nordox. Another one, copper sulphate, is almost
perfectly soluble as we know you can dump it in a bucket with some water and
watch it mix. Another one, "copper ions linked to fatty acids" i.e. copper soap or
copper octanoate is described this way by Neudorff, its maker, "rainwater readily
washes copper octanoate off plants, and this chemical is biodegraded by water
hydrolysis into its copper ion and fatty acid components".

Sooo!! What'cha talkin' about prof when ya say "fixed"?

Well, it turns out that each of these copper compounds is prepared with some
other inactive material that serves to modify its solubility and either decrease or
accelerate the release of copper ions. Copper oxide is packed into granules with
something else. Copper sulphate has lime added to it and soap is soap. Take
your pick.

But, I quibble on!! Not every product is "actually a suspension of copper particles".
Most are not "finely ground" or "coarsely ground" particles. For the most part
they are likely to be a suspension, possibly colloidal or actually in solution.

And here I stamp my little foot and cry foul! "The effectiveness of copper sprays is
highly correlated with the amount of elemental copper" Tosh! Only if you disregard
some of the products. "Begin by choosing a copper product with at least 20% or more
copper as the active ingredient to insure the greatest release of copper ions".
Baloney! How do you explain the fact that copper soap has a metallic copper
equivalent of 1.8% while Nordox is over 75%, yet both seem to work OK and
satisfy at least some of their customers.

What's going on here, prof? Or sycophant. Did you say you actually passed that
final exam?

In my opinion what matters is not the concentration of copper in the product but
the rate of release of copper ions and their persistence on the leaf surface. These
two objectives can be accomplished by a variety of methods, some of which allow
us to substantially limit the amount of copper that washes off and into our
soil. (1.8% anyone?).

OK, now the fourth paragraph is just as convoluted and obscure as the others
but my foot is sore and I'm tired of bellowing, so you guys get that one for
homework. Try to tease out the twisted statements and incomplete thoughts
for yourselves.

Meanwhile, here's another link for your personal delectation:

https://extension.udel.edu/weeklycropupdate/?p=5884

I'm sure you'll all be thrilled to know that I don't disagree with this one.