tomato powdery mildew ... help !

One of my tomato plants seems to have come down with powdery mildew fungus. A bunch of the leaves have a grey, powdery substance on them and develop spots. I've clipped off a bunch of the affected leaves/branches but would obviously like to control it. I'll probably go up to Gethsemane tomorrow but was wondering if anyone has any suggestions for an organic solution.

thanks !

Although I haven't heard of powdery mildew on tomatoes, I had some powdery mildew on my cucs and zucchini earlier this year and I used a solution of baking soda and water (1 TBSP baking soda per 1 gallon of water and add about 1 TBSP of vegetable oil - it helps the spray spread). Other growers have used a mixture of 10% milk to 90% water (skim is best I believe). If I had to do it over again, I'd probably use the milk mixture - the baking soda seemed to burn my plants a little.

There are some commercial organic choices as well but please make sure it is powdery mildew first and not blight or something else. Good luck.

Much safer to use potassium bicarb than sodium bicarb. Rate should be c. 15ml/1 Tbls per gallon. The oil isn't very good for the leaf surfaces; what you're looking for is dispersion on a difficult-to-wet surface. The easiest solution (so to say) is 3-4 drops/gal of a standard dishwater detergent--not dishWASHER detergent--rather the colored smelly stuff in the squeeze bottle at the back of the sink.

Note that bicarb has no lasting effect, it is strictly a one-shot killer process. If you're looking for some sort of two or three week product, you might very well have to go non-organic. I'm not an expert on organics (altho' I am on non-organics), but some of the things I've seen I'm very leery of, either in terms of effectiveness or in terms of side-effects.

Geo

thanks ... I'll give the detergent a shot tomorrow.

Hi,

When it is humid or prolonged rains, there are molds. If is not humid and there are molds, then you need to consider air circulation and watering methods. If you water late in the day, then try to allow time for the water to dry off the surface before sundown. A surface allowed to be damp long enough will create an environment for a spore to grow, fruit and send out spores or what you see as dust.

If the plants don't have enough air circulation, then the plants don't dry off quick enough and molds can grow. This can be a spacing issue or maybe a bit of pruning to get this in order.

Regards,