The health risks of Copper Fungicide have been seriously understated by the folks of this Reddit. Not only is too much copper highly toxic for the body, it also never leaves your soil – ever. That means you are at a higher level of copper in your body that is not only highly genotoxic, but causes sterility in mice and is now linked to Parkinson’s.
This debate gets even more interesting as I came across a Harvard health article (also listed below) which spoke about the issues with organic products in gardening as these organic herbicides and pesticides are taken up by the plant and eventually inside the produce. Even big grow products are not taken up by the plant (topical only), making much of our organic produce more harmful than our commercially grown produce.
Foodgrade DE is a great alternative that has been used for Thousands of years – used by every major civilization in human history.
So I’m just going to leave this here for those who want to draw their own conclusions:
https://www.uclahealth.org/news/release/researchers-identify-10-pesticides-toxic-neurons-involved
by Head_Dragonfruit6859
25 Comments
ya the copper sulfate thing has also seemed crazy to me especially as an “organic” option. I’ve never used it. Like really, spraying metals on everything??? huh???? it’s not surprising that it’s bad.
DE takes care of blight and mildew?
Any suggestions on alternative fungicides to battle mildew?
What about potassium bicarbonate for mildew? People take it as a supplement.
Wow! I’m so glad I read this!
I was ready to call BS, but those are some solid sources. UCLA directly calls out Copper Sulfate. Beyond pesticides, any blue crystalline fertilizer is mostly copper sulfate as well (aka Miracle Grow).
IIRC the copper spray i use (captain jack) is copper Octanoate, wonder how that compares to sulfate.
How would you use DE to help fungus?
This is really interesting – I had no idea. I don’t use it excessively, but I have been using the Captain Jack Copper Fungicide (active ingredient copper octanoate) to try to control some pretty aggressive septoria leaf spot on my tomatoes this year. I’m not sure if I bought contaminated mulch, or if it’s just due to all the rain we’ve had, or both. I wonder if there’s any research on whether different forms of copper (eg, sulfate vs octanoate) are more or less safe.
Would DE be helpful to contain septoria leaf spot? And if so, how would you apply it, and what are your concerns about harming beneficial insects with DE?
Are there any other products/solutions you might recommend aside from DE? I’ve also tried Dr. Zymes which is citric-acid based as I had great success with it previously to eliminate powdery mildew, but their label actually doesn’t list septoria as something it helps to control.
I refuse to use sprays. I’m not going to drink fertilizer so maybe that’s the solution. Just don’t use sprays even if you have to sacrifice a plant or all of them.
I’ve managed to completely remove blight/fungus disease from garden. For the third year in a row I’ve got tomato leaves still touching the ground in August without a single blemish of Blight. That would have been impossible years prior. All I did was start using cover crops in the Fall in my raised beds, and companion plant my tomatoes with crimson clover in the spring (also allowing certain “weeds” like purslane to grow as well.). Apparently biodiversity keeps disease at bay. Who would have thunk it! I made no other changes. In three years we’ve had record rains, record drought and all kinds of crazy weather. I grow all the same tomato varieties I did before. Not a speck of Blight. I used to use copper fungicide to fight the blight. Glad I no longer do.
Thank you for posting the science links as well!!
dang. back to need oil for me then.
Ugh I’ve been debating using copper spray to try and treat bacterial wilt in some of my beds. But I think I might go with leaving them fallow and laying trash bags on them to cook it out instead.
Food grade DE has let me down as a pesticide, I haven’t tried it for fungal control. I have read about people who use dilute hydrogen peroxide which I have used when I grew weed. I may have to see what is a safe level for that on tomatoes.
While copper sulfate is definitely not great, let’s not just gloss over the fact that diatomaceous earth is literally silica dust, and respired cristobalite from DE is directly correlated with [silicosis](https://www.atsjournals.org/doi/full/10.1164/ajrccm.158.3.9709103RadiographicEvidenceofSilicosisRiskintheDiatomaceousEarthIndustry%7CAmericanJournalofRespiratoryandCriticalCareMedicine) ([another study](https://pubmed.ncbi.nlm.nih.gov/11836467/Exposuretocrystallinesilica,silicosis,andlungdiseaseotherthancancerindiatomaceousearthindustryworkers:aquantitativeriskassessment-PubMed)). Parkinson’s isn’t pretty but neither is dying of miner’s lung at 35.
Use it, sure, but be aware of its health effects and how to protect yourself.
What about pollinators and other beneficials in your garden that you like and want to stay there? Won’t DE harm them indiscriminately?
I literally just sprayed Captain Jack on my cherry tree because it had leaf mold spots about an hour ago. I felt like a dork because I was wearing a hoodie and goggles. Now I’m glad I did. I kind of wish I read this first, oh well.
Thanks for posting this. I am guilty of freely using preventive copper spray to limit the intrusion of fungal disease in my tomato patch. Have used DE for insect pests in the garden, but have never looked into it for this. Appreciate the solid links to articles with good science. I will study this issue carefully later tonight and quite possibly modify my approach for next season.
Not an excuse, of course, but my climate (NE Texas, 8a, hot and damp) coupled with my particular back yard growing conditions makes for high fungal disease pressure. I live next to a seldom-used municipal youth-league soccer field with a serious drainage problem. During rainy season, it becomes a disease reservoir. So, if I don’t pay close attention to prevention, I can count on losing my entire tomato crop.
In recent years, I have rotated copper octanoate with chlorothalonil (Daconil) and this past year, followed a three-way preventive spraying program that included Mancozeb (a zinc compound) as well. Obviously, I’m not proud of using so many chemicals and am open to reasonable alternatives.
Will DE work on septoria leaf rot? I appreciate you posting this as I like science and am not into the woo. That said, I had some pretty bad leaf rot on my tomatoes this year and I used a product with copper fungicide in it. 😬 I have regerts now. It worked super well, not a fan of Parkinsons.
I live in a very hot & humid area on the NC coast & fungus is a huge battle every year not just with my tomatoes but basically with all my plants. Last year I used Neem oil mostly but it wasn’t effective. This year I’ve been using copper & fungonil pretty heavily with more success but after reading this now I don’t know what to do. I do treat my soil with DE before planting but I think this climate is challenging. I do have a biofungicide called Revitalize & I wonder if that’s any safer
Thank you for letting us know. I stopped using it a few years ago but didn’t realize how dangerous it was
https://preview.redd.it/1zt0rylx6ihf1.jpeg?width=939&format=pjpg&auto=webp&s=82e20ce16a9a542517c0c3cff06596eb29f5ce16
Wish I had read this a few days ago before I sprayed all my stuff with it.
I just used miracle grow bloom booster on my squash, pumpkins, and some peppers today. I am worried what this means for safe eating. I haven’t used it often this year. Last year I used lots. Yikes