Fungicide question for the chemically literate

I looked at the UC Davis fungicide trials for the first time in several years tonight https://ucanr.edu/sites/eskalenlab/files/316471.pdf. You have to go to pg 22 to get some quickly digestible results. PerCarb and Oxidate seem pretty benign and perform pretty well. My question is whether these specialty products are the same thing as the stuff we buy more cheaply for winery sanitation. As far as I can tell, PerCarb https://2cpx6j45416t43itfm2y6enr-wpengine.netdna-ssl.com/wp-content/uploads/2019/12/percarb_label-california.pdf is the same thing we buy relatively cheaply from ATP as sodium percarbonate. Oxidate http://horizon.wiki/images/a/a4/BioSafe_Systems_Oxidate_2.0_Fungicide_Label.pdf is a little more involved, in that it combines a little bit of paracetic acid with hydrogen peroxide. But those are pretty normal, and not especially costly, winery chemicals. I ordered some Oxidate for my next, and maybe last, spray, but after I looked at it a little further, I started to feel like a sucker.

Stewart - My experience with Oxidate-2 is that is not very effective as a fungal spray on grapevines. Only marginal activity on powdery mildew found on foliage but sun exposure takes care of that for the most part. I have not found it effective for powdery mildew on fruit. That being said I do find it works wonders on squash and cucumber powdery mildew. Oxidate-2 is the peracetic acid(PAA)-hydrogen peroxide blend with only 2% PAA which is much lower than the winery sanitation solutions I have seen.

Well, I went ahead with the ProxyCarb (Sodium Percarbonate, as a substitute for PerCarb) from the cellar about ten days ago, as an experiment. No apparent phytotoxicity. As to efficacy, there was no observed mildew before or after. Hard to say anything with a great deal of confidence. I was less comfortable winging it, substitution-wise, with Oxidate, because it has two active ingredients (hydrogen peroxide and peracetic acid), though both are familiar enough individually. As I said previously, I felt like a sucker for paying many multiples of what it should have cost, but went ahead and sprayed it today anyway. These two sprays together substitute for my usual closer, Pristine. I normally spray mineral oil for everything but the last spray, and I’ve liked having something with “locally systemic” qualities after bunch closure. PerCarb and Oxidate require direct contact, which makes me a little less comfortable, but they they potentially check a lot of boxes for me – efficacy against both mildew and botrytis, eradicant and protectant efficacy, potentially cheap, and benign chemistry. This is a good year to try it because the canopy is well under control. In a more vigorous year, with less good spray coverage, I might have had more qualms. We’ll see.

Hey Stewart,
Maybe you can get away with that as an owner/operator. For commercial operations all pesticides (chemicals applied to reduce the population of any living organism) must be registered with the EPA and the use of which must be reported to the county.

I think of it like taxes on Alcohol. Vodka should be dirt cheap, but due to taxes, regulation, and costs of bureaucratic administration, it costs $10 for a bottle of Popov instead of $2. There may also be purity standards which make the direct comparison different.

Cheers,
Benjamin
Licensed Pest Control Advisor
Biochemistry BS
Horticulture MS