Could be the vinegar.

Thanks for checking out the link, jean.

So, at this juncture, you don't think it's a fungal or bacterial condition?

Thanks.

Kevin

Correct. Not a disease.

If it's not the vinegar, it could be the combination of everything else you've been applying. I'm not sure that I understand the concept of "pretreating for powdery mildew " with vinegar! Did you know that PM spores can be rinsed off leaves with plain water before they infect the cells? One needs to be extremely cautious about using vinegar on foliage; it is used as an herbicide at strong doses.

This post was edited by rhizo_1 on Sat, Jul 6, 13 at 6:50

Thanks rhizo and Jean.

Rhizo: I really don't spray a lot. So far this year, I've done a few water treatments and ONE soap for aphids. Other than that, my usual BT applications every 2-3 weeks. As fae as the pm is concerned, I do realize that just plain water will wash off SOME spores, but overhead watering isn't particularly good for peppers. Next thing I knew, we had a monsoon off the Pacific and started noticing the PM show up on my cucurbits. I was going to do a neem treatment, but after inquiring, found out that may not be the best thing with the temps in the 100's. So I went with a very mild 3TB/gal apple cider vinegar solution and put the plants in question under the patio. None of my other plants(in direct sun) exhibited the discoloration.

You may be right about the combination -- I normally just use fish ferts as a soil drench but this time I did a foliar sprinkling with it on those plants on the patio. A few days later did the vinegar... so maybe there was a reaction.

Thanks again.

Kevin

Edit--- double post.

This post was edited by woohooman on Sat, Jul 6, 13 at 16:29

Since vinegar is used as a "weed" killer why would anyone use it to treat a simple to control disease like Powdery Mildew?

PM info at UC Davis.

kimmsr: EVERYTHING, in excess, can be toxic. I can actually drink too much WATER. The milk solution that is a remedy for PM has actually been known to be harmful when the milk is at a high ratio to water.

The apple cider vinegar solution I used was actually lower in ratio than the recipe called for -- 3TB/Gal water. It's a moot point now -- since I saw discoloration, vinegar has been nixed from my list.

If I had used neem oil during the heat wave, I probably wouldn't have seen any MORE damage.

Kevin