How do you prevent mildew and fungal blights in the garden?

In recent years my garden gets hit with fungal outbreak around mid summer that eventually wipes out my tomatoes, cucumbers, and squash. It seems to hit worse after weeks of no precipitation combined with high heat and humidity. I was thinking of using a preventive copper spray when I see this weather pattern emerge. Any suggestions?

Yes, I have had problems too. I use a number of products. Tomatoes are tough to treat as eventually they succumb to some fungus. At least here. It’s trying to keep them alive to produce first. I like using Fung-onil or Daconil and Agri-foss.
Here tomatoes will die of early or late blight, septoria spot or downy mildew. Both products protect against most of these problems.

This year I’m going to feed with a seaweed foliar spray as I heard that the product prevents powdery mildew. Once it’s bad it’s hard to stop. You can spray it off then use an all seasons oil. It slows it down for about week.

And yes the coppers are good as a preventative.

Thanks. When do you start with the antifungal sprays? I’ve used copper before. but started too late for it to be effective. It seemed like it kept the plants alive, but they never produced well after that.

I have not used copper on most of my plants. Just cane fruit, and trees. I use mostly the other products. I have only had problems on tomatoes and vines. I’m still working on the vines. Lime-sulfur is also a great preventative but is unavailable. I have some, one bottle left. I start them soon after plant out. I’m spraying Agri-foss today on tomatoes and peppers.
I would try the copper on the vines. I only have Copper hydroxide right now, and that is strong stuff. I’m afraid to use it on the vines. I’m going to use Agri-foss, lime-sulfur, and pure seaweed foliar spray. probably.
And yes once they have it, well good luck! You have to start now before they get it.
I may buy some liquid copper myself just for vines.
So i would start at plant out, or at least 3 weeks ahead of expected infection time. As you said mid-summer.

Depending on the species of mildew in your area, a foliar spray of seaweed extract can promote the growth, not deter it.

I was just quoting the CEO of Neptune’s Harvest.

Also from others
Powdery mildew is common where plants are deficient in potassium and
some trace elements, as when the plants have exhausted their supply of
fertiliser, or when they cannot absorb nutrients because soil is too
dry. Seaweed extract is rich in both potassium and a range of trace
elements (including sulphur), and spraying foliage with seaweed tea can
be effective against powdery mildew, not because it kills the fungi, but
because it quickly provides the nutrients plants require to resist
these fungi. -

Safer brand also uses seaweed for powdery mildew.

More examples

Not one mention species that it helps…

I sell Seaweed Extract too but I don’t recommend it for that purpose.

Yeah I’m pulling all weapons out to keep it away. I just purchased some liquid copper. It’s easier and safer for me to use for mildew. Plus I’ll foliar feed with seaweed. I need to find a way without using lime-sulfur, which i will run out of soon. I like saving it for a late fall dormant application to my trees with oil.

Serenade is a bacteria strain.
Organic gardening theory is increase the good and decrease the bad.

Biological Pathogen Control from AgraQuest protects against many plant diseases, including black spot, powdery mildew, rust, gray mold, leaf blight and scab.
Contains a unique, patented strain (QST 713) of Bacillus subtilis
Controls diseases such as Fire Blight, Botrytis, Sour Rot, Rust, Sclerotinia, Powdery Mildew, Bacterial Spot and White Mold and more.

If you try Seranade, you must test each plant, it can burn leaves badly on some plants. I never used it, but label warns of damage to leaves. You can also get it cheaper with free postage on Amazon.

Thanks David. I have actually heard about this long time ago but completely forgot about it. Do you use it?