Powdery mildew question

[Francis Barnswallow]

Been noticing more and more powdery mildew on my tomato leaves. I pick off the infected ones and used organic spray and its not taking care of the issue. It's been pretty dry lately and I only water the base of the plants, never the leaves.

Any suggestions on how to get this powdery mildew under control?

[Dillbert]

what kind of "organic spray" did you use?

[applestar]

When powdery mildew season arrives, I spray everything -- vegs, fruit trees, roses, magnolia -- down with milk spray. That's the only time -- really -- that I go around indiscriminately spraying everything (that catches powdery mildew or other fungal diseases).
I just use the hose end tree and shrub sprayer which I believe dilutes to 1/8.

Well, actually I alternate weekly with AACT.

[hendi_alex]

I use wettable sulfur spray with good results. Mildew is not a major problem in our garden, as the conditions that favor growth only occur sporadically. That is one of the major benefits of succession planting. One batch of plants might get affected but by the time the next batch comes along, the mildew is no longer actively growing and spreading.

[Francis Barnswallow]

what kind of "organic spray" did you use?

I used this recipe.

http://organicgardening.about.com/od/di ... aspray.htm

[Dillbert]

baking soda is one of the classic sprays - as mentioned milk and sulfur based are also useful, along with a number of others.

this site is not strictly organic - but this is one of the better primers on powdery mildew:
http://urbangardenmagazine.com/2009/08/ ... droponics/

note that (essentially none) of the spays are 100% effective "one time" - and also there are a couple different fungals that comprise "powdery mildew"

if the situation continues, I would suggest rotating the spray type(s) as one or another may be more effective against the particular strain you're battling.

[rainbowgardener]

I agree with rotating different methods. Along with baking soda solution, milk solution, AACT, the other choice would be hydrogen peroxide.

[imafan26]

Fungal diseases are best prevented than cured. When weather conditions are favorable for fungal disease, susceptible plants should be sprayed weekly as a preventive.

The humidity after rainy days, and leaves that stay wet overnight are conducive to fungal growth

I spray before, if I know rain is coming with an oil. Neem is antifungal, but I prefer to use horticultural oil instead. The oil coats the leaves and helps them to shed water.
I would follow up with baking soda spray after the rain to help keep the leaves dry.

If I am late in treating the plants and I have not used an oil within 2 weeks, I use the sulfur. If it rains again, I need to reapply sulfur every 3 days or so.

[Francis Barnswallow]

Yeah we've been getting crazy amounts of rain this april. Got over 3 inches in just two days. I keep spraying and picking off leaves were the mildew is forming. So far, I think it is working. *knocks on wood*