copper spray

[encore]

does it hurt to spray plants as a preventative with copper spray? in case it is something but your not sure?

[gorbelly]

Antifungal treatments are supposedly most successful when used as prevention and not just as treatment, although there is plenty of philosophical debate about whether preventive spraying is "good" in a larger sense or not--but that's largely down to personal belief and personal choice.

No, it won't hurt your plants, as long as it's a treatment designated for tender plants like garden vegetables and it's used at proper dilution, etc.

I generally only use treatments that can be used up to the day of harvest. That's a personal choice. Others use more powerful treatments, such as chlorathonil (Daconil).

Last year, I used Bonide's copper antifungal, but didn't start using it until I saw signs of disease. I was convinced by the many experienced tomato growers who use fungicides from day one of plant-out, so this year, I'm alternating the copper with Serenade and have already been treating the plants since they went out. I spray after significant rain (anything that's enough to wash the treatment off of the plants), but if we have a couple of days of on and off rain, I'll wait until they're past. This works out to about once a week or two weeks where I am.

Even certified organic copper formulations are somewhat toxic, so avoid skin contact. It can also be toxic to aquatic wildlife, so don't spray near a pond if you have fish and amphibians in it, etc.

[encore]

will using the spray bother the blossoms at all as far as pollinating?

[ginger2778]

Originally Posted by encore

will using the spray bother the blossoms at all as far as pollinating?

A large concentration of copper ions is definitely phytotoxic. More is not better. I use at 1/2 of the weakest recommended strength, with a little squeeze of real soap, rather than detergent, and avoid the blossoms as much as you can.
If your leaves look blue after spraying, your solution is too strong. Copper when too strong will stunt and curl new growth and it takes about 3 weeks for the plant to recover.

[Lindalana]

Even gentle antifungal and antibacterial methods will ruin good stuff that lives on the leaves as well.
So using one and skewing your microbes proportion can lead to unexpected rise in different things.
Me- I am hesitant to use much of anything because I have ladybugs and all good stuff in the garden doing their job.
However, one has to decide when to interfere. I use Copper to wipe out bad stuff but then I use something like Microbelife and Aerated compost tea to bring in and support good stuff that protects my plants. You need Light and Biology to grow happy healthy plants. You can not keep wiping biology by insecticides/ pesticides/ fungicides and expect plant to be healthy- my opinion.

[Yak54]

ginger2778

Very good point about copper stunting & curling new growth when it's too strong. I just had to pull out and replace one of my Dr. Lyle plants that got curled and de-formed leaves the top 1/3rd of the plant, about 3 days after I sprayed them with copper. Almost looked like herbicide damage, but I know better.

[ginger2778]

Originally Posted by Yak54

ginger2778

Very good point about copper stunting & curling new growth when it's too strong. I just had to pull out and replace one of my Dr. Lyle plants that got curled and de-formed leaves the top 1/3rd of the plant, about 3 days after I sprayed them with copper. Almost looked like herbicide damage, but I know better.

Thank you.
You don't have to pull them if you see that stunting in the future. They will grow out of it, it just takes them about 3 weeks to catch up. I have been there with overly strong copper spray snd stunted leaves, and I learned the hard way that more isn't better.

[gorbelly]

Originally Posted by ginger2778

A large concentration of copper ions is definitely phytotoxic. More is not better. I use at 1/2 of the weakest recommended strength, with a little squeeze of real soap, rather than detergent, and avoid the blossoms as much as you can.
If your leaves look blue after spraying, your solution is too strong. Copper when too strong will stunt and curl new growth and it takes about 3 weeks for the plant to recover.

Which is why I stressed proper dilution.

I follow the instructions on the bottle. I've never had issues with it hurting blossoms or affecting pollination. I only spray late in the evening after the bees have gone home. I also use a sticker-spreader (Coco-Wet) in my solution instead of soap, which makes it easier to get good coverage using less spray, both a money saver and insurance against potential excessive copper buildup in the soil. I never use soap in any foliar treatments, as the one time I used soap, even though it was a tiny amount, some of my leaves were burned.

If copper solution collects at the tips of leaves or in cupped or very rugose leaves, and it dries like that, there will sometimes be a little blue tinge remaining in those specific areas. I've never had it hurt my plants except for that one time I mentioned earlier that I used soap as a surfactant.

As I said, I alternate with Serenade, as the one study I found on it showed that copper and B. subtilis alternated worked better than either exclusively.

[cwavec]

Coco-wet, according to the manufacturer's description, appears to be only a
wetting agent. In other words, only a spreader and not a sticker.

[gorbelly]

Originally Posted by cwavec

Coco-wet, according to the manufacturer's description, appears to be only a
wetting agent. In other words, only a spreader and not a sticker.

Correct. My bad. I'm used to saying "sticker-spreader" for this category of additive.

It's just a surfactant, which lets the solution actually coat the leaves easily until dry instead of rolling off, which helps me use less spray overall. I personally prefer not to use anything that "sticks" on food crops.