nor,

I've been battling Powdery Leaf Mildew (Mold) for the past few years. These darn Crap Myrtle trees here in San Jose are ground zero for harboring the affliction.

{{gwi:32057}}

Last year, I used Actinovate, as well as Serenade with modest results. I am now trying something Ami tipped me on to called Exel LG. Preliminary results look promising.

Raybo

Here is a link that might be useful: Exel LG

Thanks Raybo!

That looks EXACTLY like what I've been battling. Thanks for the exel LG suggestion, at this point I'll try anything! The fight continues...

nor,

I bought mine online from www.lawnrite.com. They had the best price and shipping. $28.00 delivered for a Quart of concentrate that makes 32 gallons.

Raybo

rnewste,

The mildew on crape myrtle (genus Erysiphe) is different than the mildew on tomatoes (genus Oidium). So don't yell at the trees.

I'm fighting the same battle here in VA. Only treading water with serenade as it is raining every 4 days and the powdery mildew pops back up. Part of the problem is me and timing the spray so that I have dry weather for a couple of days. Several times I've sprayed and the next two days it rains and the powdery mildew takes hold on the peonies and tomato leaves. A lesson learned that next year I'll start spraying once I plant outside. Will also try Exel LG and post back. The mildew is on the march again with the newest rain storm. LOL but atleast my plants are growing this year now that I've switched from MG orgainic soil to MG potting soil ....what a difference. Thanks Ray for your insight on container growing.

George

There are two kinds of Powdery Mildew, one called Oidium, which Jeanne mentioned above and the other one caused by Leveillula and the symptoms are not exactly the same and both can be found in CA and many other places as well.

Southern CA is best known for their June Gloom period with fogs, etc, and Oidium is usually the cause.

Several suggestions have been made above for what to use to control it or possibly help even prevent the spores from germinating, and I'll just add the following if you folks promise you waon't get off on a diatribe about it, but Daconil, as in Ortho Garden Disease Control has worked well for many folks.

Another suggestion for Oidium specifically is to spray with sulfur.

Carolyn

Thanks so much everybody for the advice and suggestions.

I'm in the midst of June Gloom here and I'm sure it's probably helping the mold flourish...

Will report on the results!

I use Neem oil. Cheap, safe, and effective. I use it once a week as a preventative. Although I took a vacation this year and when I got back it was too late for some of my plants.

Neem Oil has been very effective for me also. And I have some of those darm crepe myrtles :~). Works best when using as a preventative before problems show up. No matter what I do though, seems powdery mildew of all sorts is a constant challenge.

Despite the name, PM is not a mold or mildew but a fungus. MOST species of PM spores are killed by good ol' water! PM of Tomato just happens to be one of those that doesn't require moisture for spore germination and therefore will be stopped in it's tracks by water! Try that before chemicals if possible. Just be careful to get the leaves wet (undersides too) in time to dry before nightfall to avoid other fungal problems.
Now if you have Downy Mildew that's a different story....these thrive with free moisture.

vera,

Thanks for the information on it being a fungus. In any event, when I first sprayed Serenade on the Crap Myrtle tree next door, you could see a cloud of spores like dust, rise up off the tree leaves, and kind of float in the wind. Trust me, whatever this is, plain ole water is not a cure. This tree has been infected for the past 3 years, and rainwater / hose spraying doesn't bother the growth at all.

Raybo

Just an update - the mold seems to be at bay after using the Ortho stuff. I've also just gotten the Exel and will probably try it as a less toxic solution. I think I got to the mold just in time - it really has been aggressive and awful. I'm going to have to keep a real eye on the plants to make sure it doesn't reappear. We didn't have the oidium problem last year, but also started planting much later in the season.

Next season, it's all about prevention - live and learn, we have discovered. Every year you discover something you "should have" done.

Thanks for the help - this site has been a wonderful resource!

Sorry to restart this old thread, but I've just started seeing this problem too. While I look for Daconil or Excel, etc, do I need to segregate the infected container from the rest of my tomatoes? (or is it already too late as I just can't see the spores in the other containers?) Will something like this destroy my crop (a la late blight) or is it something the plants can "grow out of?"

One additional question. Should I clip the leaves that have the mold spots?

Chlorothalonil (a.k.a. "Garden Disease Control" by Ortho; formerly known as "Daconil") is my favorite. Dr. Caroline has already mentioned this. It stops mildew dead in its tracks around here. Add an adjuvant to your tankload. Maybe some permethrin insecticide, to boot, to kill cabbage loopers, which are common at this time of year.

I would carefully snip the conspicuously infected leaves first, being careful to keep the parasite from spreading.

Powdery mildew- wash the plants down with water daily. use Neem oil as directed. It took down my cucumbers, leaving everything else alone. Now I am sure it will find my zuchinni!