Copper Fungicide

[Gardadore]

I am having a problem with excessive yellowing of leaves on some tomatoes. I keep removing them but soon there will be nothing to cover the tomatoes on the lower part. Other tomatoes have this brown to gray spots on the edges of the leaves and they are drying up. Also remove them daily. Is this possibly gray mold? I understand Copper Fungicide is good at clearing that up. My question is whether it is safe to spray the whole plant and the tomatoes as well. It will be pretty hard to avoid the tomatoes if I spray the leaves. This will be my first time ever using Copper Fungicide so any advice on how to use it will be most welcome!

[KathyDC]

It shouldn't hurt the tomatoes. I think you may need to wait a few days to eat them after spraying, though.

[Ginger2778]

I am having a problem with excessive yellowing of leaves on some tomatoes. I keep removing them but soon there will be nothing to cover the tomatoes on the lower part. Other tomatoes have this brown to gray spots on the edges of the leaves and they are drying up. Also remove them daily. Is this possibly gray mold? I understand Copper Fungicide is good at clearing that up. My question is whether it is safe to spray the whole plant and the tomatoes as well. It will be pretty hard to avoid the tomatoes if I spray the leaves. This will be my first time ever using Copper Fungicide so any advice on how to use it will be most welcome!

It's safe. I use it throughout the season, every year. Spray liquid copper fungicide at the weakest recommended strength. If it looks blue on the leaves it's too strong. A little goes a long way. It is OMRI listed as an organic fungicide, and plants need copper.
Try to avoid the flowers as much as you can, because a lot of spray will cause flowers to shrivel.

[pepperhead212]

Try to pick all of the tomatoes, including those just starting to ripen. That way, by the time you have more ripening, there shouldn't be any problem with it.

I try not to use copper, unless it's really bad, like last season. This year, and better years, like this, I use potassium bicarbonate, as a prophylactic, spraying weekly. Years ago, some tests were done with baking soda (sodium bicarbonate) versus copper as a "cure", and when they mixed 1 tb with 1/4 c oil, it helped as much as the copper. However, the oil can't be used at temps over 90°, so that cure is pretty useless to most of us in the summer! While baking soda is cheaper, you don't want to spray it weekly, to avoid adding all that sodium to your soil, and water table. The potassium is actually adding fertilizer, though I don't think of it that way. I just bought another 2½ lbs of potassium bicarbonate, and that much lasted me for a little more than 3 years.

[loulac]

I try not to use copper, unless it's really bad, like last season.

A very sensible decision. Copper will stay in the soil and never disappear and becomes toxic when it reaches a certain concentration. Some vineyards in the Bordeaux area have become sterile due to the high concentration of copper. Personnally I use copperonce in June for protection against early blight and once in October to fight late blight. After every rainfall I prefer using sodium or potassium bicarbonate which are biodegradable.

[Ginger2778]

I try not to use copper, unless it's really bad, like last season.

A very sensible decision. Copper will stay in the soil and never disappear and becomes toxic when it reaches a certain concentration. Some vineyards in the Bordeaux area have become sterile due to the high concentration of copper. Personnally I use copperonce in June for protection against early blight and once in October to fight late blight. After every rainfall I prefer using sodium or potassium bicarbonate which are biodegradable.

I think it's safe at the doses I recommend. I use liquid copper fungicide at 1/2 of the weakest recommended strength, which is effective, I recommend using it at the weakest recommended strength. The OP wanted to know if it was safe to eat the fruit after spraying. Wash the fruit and it is, but always read the label for that info, they all print it.

[Gardadore]

I don’t want to pick the tomatoes because they are not even ripening yet and some are very large. Does the potassium bicarbonate work on the gray mold as well? What other diseases does it help? The copper arrives today and we are finally supposed to get some rain today and tomorrow so will wait till that is over.
Thanks for all the advice. My tomatoes are full of flowers as well. Maybe I’ll start with a couple of plants and see how it goes following Marsha’s advice to use a weak dilution. No matter what I would obviously wash the tomatoes first. If the copper stays in the soil wouldn’t it penetrate the tomatoes too? My tomatoes are mainly in straw bales.

[Ginger2778]

I don’t want to pick the tomatoes because they are not even ripening yet and some are very large. Does the potassium bicarbonate work on the gray mold as well? What other diseases does it help? The copper arrives today and we are finally supposed to get some rain today and tomorrow so will wait till that is over.
Thanks for all the advice. My tomatoes are full of flowers as well. Maybe I’ll start with a couple of plants and see how it goes following Marsha’s advice to use a weak dilution. No matter what I would obviously wash the tomatoes first. If the copper stays in the soil wouldn’t it penetrate the tomatoes too? My tomatoes are mainly in straw bales.

Plants need copper, and actually so do people. If the tomstoes are still growing and you don't respray, and you wash them, you should be fine. I dont believe it penetrates tomato skin, its solid. Leaves and roots have pores.

[Ginger2778]

Personally, at 1/2 of the weakest recommended dose, I don't even worry about it. Again, it is accepted and listed as an OMRI fertilizer, for specifically organic use. This is beginning to feel like antivaxers thinking, about the dangers of an accepted organic fungide for decades.
Theres always research, as long as you use a .org source, not a .com.

[loulac]

[quote=Ginger2778 post_id=26276 time=1595416341 user_id=54]
I think [copper] is safe at the doses I recommend [quote]

I'm sure it is, the point to remember is the slow accumulation of copper in the ground. We won't have problems but our great great grand children may have difficulties with gardening, though we can hope new techniques will enable gardeners to clean the soil efficiently. Let us use copper sensibly and we won't have any guilt complex , just a bit of blue at the end of leaves allowed !

[Ginger2778]

I go even a bit further. I say if you can see any blue on the leaves, it's too strong.

[loulac]

cwavec is part of the top team of tomato disease experts together with b54red of course. He recently posted on a well known tomato site (key words : “anti-fungal sprays”). He introduced me to copper soap, sold under the name of actinovate but not in all countries. It gives full power to metal ion Cu 2+ and Cu dosage can be quite low. I suspect chemical lobbies are fighting its diffusion. The thread describes other antifungal products that look interesting. Has anybody tested actinovate ?

[pepperhead212]

cwavec is part of the top team of tomato disease experts together with b54red of course. He recently posted on a well known tomato site (key words : “anti-fungal sprays”). He introduced me to copper soap, sold under the name of actinovate but not in all countries. It gives full power to metal ion Cu 2+ and Cu dosage can be quite low. I suspect chemical lobbies are fighting its diffusion. The thread describes other antifungal products that look interesting. Has anybody tested actinovate ?

Actinovate is NOT copper soap, or any copper substance of any type! It is a bacterial spray, which works well, but I have found it best as a prophylactic, and that it doesn't work as well to kill the fungus, once it has set in. I usually use it early in the season.
https://mycorrhizae.com/actinovate-biol ... tile-tool/

The copper soap is what I use, as last resort, as it works well, but uses less copper than other applications. Ans even though copper is listed as "organic", it really should be used with caution, as it kills some beneficials, as well as the fungus. And it can build up in the soil.

[loulac]

Actinovate is NOT copper soap, or any copper substance of any type!

I stand corrected, I should have written "copper octanoate". It was a slip on the keyboard. I tried to find Actinovate in France but its use is not allowed and Amazon etc refuse to ship it to the country.
I quite agree copper octanoate will leave metal copper in the soil, but in smaller quantities if we spray a weaker solution. What dose can you suggest ?

[Ginger2778]

Actinovate is NOT copper soap, or any copper substance of any type!

I stand corrected, I should have written "copper octanoate". It was a slip on the keyboard. I tried to find Actinovate in France but its use is not allowed and Amazon etc refuse to ship it to the country.
I quite agree copper octanoate will leave metal copper in the soil, but in smaller quantities if we spray a weaker solution. What dose can you suggest ?

Dosing ranges are on the written labels the solution comes with. I use 1/2 of the very weakest recommended dose, it differs for different brands and types of material.
Actinovate is a biological fungicide. There is no copper in it at all.
https://www.amleo.com/actinovate-sp-bio ... YwQAvD_BwE

[loulac]

Thanks for your fast an informative answer.
I've stopped looking for actinovate a few years ago as I could find more or less identical products locally and the only disease I have to fight is blight.
The most important sources of octanoate seem to be out of stock at the moment. I don't see it as a real concern as I can make copper soap, but finding the right dose will need careful experimenting.
I forgot to say I use bleach from time to time, following b54red's instructions, not forgetting the soil, hoping to kill spores that would germinate the following year.

[Ginger2778]

[mention]loulac[/mention]

Screenshot_20200725-115344.png

This is the one I use, and it's a different copper than soap or octanoate.

[loulac]

Let me first renew my thanks.
This product has no actinovate but its proportion of metallic copper equivalent is impressive : 8%, which is the essential point. Now I know where I can go. Thanks again for helping me all along.

[Ginger2778]

Let me first renew my thanks.
This product has no actinovate but its proportion of metallic copper equivalent is impressive : 8%, which is the essential point. Now I know where I can go. Thanks again for helping me all along.

You're welcome , it's my pleasure.