What do you use for disease control/prevention?

Hi - I'm in the Central Florida area (North Tampa, specifically) and am getting my tomato seeds going. I'd like to be proactive this year since last year I lost some plants to powdery mildew in the spring. What do you do to prevent things like that? I use BT for worms and have had good success with it, but what can I do for powdery mildew prevention? They guy at Home Depot said I can use neem oil or copper as preventatives, but I've read elsewhere that's not true. I'm a bit confused. I'd like to keep things as natural as possible. Any help would be appreciated, as I'd like to start some program as soon as the transplants go in. Thanks!

Here is a good reference site to read about Powdery Mildew.

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7406.htm

I had powdery mildew on my summer squash this year. I had four plants and they all got Powdery Mildew. I had four different types of products that said they worked to control Powdery Mildew but not eradicate it. I tried an experiment with the following four products:

1) Daconil - suggested by the county extension office - (ortho multipurpose fungicide - daconil 2787). Expensive, not organic, hard to apply because of consistancy, didn't work very well and about killed the plant, (or may have killed us if the plant had produced).

2) Flowable Liquid Copper Fungicide (Gardens Alive). Did not eradicate the disease but controlled it enough that I was able to harvest squash up until frost. Need to apply every 7 - 10 days to keep PM controlled, Expensive.


3) Plant Guardian - Biofungicide Liquid (Gardens Alive). Worked about the same as number 2 above. Expensive.


4) Home Made Brew - Worked just as good as number 2 & 3 but cheap to make and always available ingredients around the house. There are many recipies on the web, but here is the one I used: 22 oz fat free milk, 33 oz water, one drop of dishwashing soap, 1 tsp of baking soda.

But the link above lists better alternatives.

I have no direct experience with this being much of a problem luckily, but I have found this...

It seems proper air flow is needed... so don't crowd the plants too much, even if it means pruning the excess leaves to allow airflow thereby decreasing relative humidity around the leaves. The disease is common in crowded plantings where air circulation is poor and in damp, shaded areas. Incidence of infection increases as relative humidity rises to 90 percent, but it does not occur when leaf surfaces are wet (e.g., in a rain shower).

I have read several different places that washing the leaves with water in the morning only so they have time to dry is helpful to wash off the spores.

Too high of nitrogen content of the soil has been implicated they think because there is an explosion of many new leaves which are tender and easier to infect. So I would watch adding things like a spray on fertilizer. If you do, I would think pruning to allow a number of holes for air to flow around the plant might be in order.

Another option is to spray once a week with a solution of baking soda. Baking soda increases the surface pH of the leaf making it unsuitable for the growth of powdery mildew spores. Be sure to spray the undersides of leaves as well as the upper surfaces when using any of these sprays.

The use of baking soda as a fungicide is not a new idea. In Alfred C. Hottes' A Little Book of Climbing Plants, published in 1933 by the A.T. De La Mare Co. of New York, mention is made of using one ounce of baking soda per gallon of water to control powdery mildew.

Here's a recipe to make your own spray:

1 teaspoon baking soda
1 quart water
A few drops of liquid soap

Before treating your plants, test the spray on a few leaves to make sure they are not too sensitive.

Another spray recipe:

An alternative nontoxic control for mildew is baking soda combined with a lightweight horticultural oil. Researchers at the University of Rhode Island have confirmed that a combination of 1 tablespoon baking soda plus 2.5 tablespoons oil in 1 gallon of water is effective against powdery mildew. Test on a few leaves first.

Mark

Last summer I used the baking soda, dish soap, and water solution on my summer wine ninebark bushes with very good results. Ninebarks are notorious for powdery m. The bushes are 5 years old and never looked better.

llama momma wrote:Last summer I used the baking soda, dish soap, and water solution on my summer wine ninebark bushes with very good results. Ninebarks are notorious for powdery m. The bushes are 5 years old and never looked better.

I also had good results with this spray solution on my cukes & some of the squash plants.

Thanks for all the replies! I really like the baking soda idea since it's both natural and inexpensive. I will definitely try it this year. It just makes sense that the ph would inhibit the mold growth.

I had a great deal of trouble last year with both PM and DM on a number of plants in my garden along with early blight on my toms. The plan this year is first planting only tollerent and resistant vegies. Also going to try treating weekly with soap shield before any probles start, last but not least I will mulch, I am very careful not to splash my plants when watering but one good rain storm and there is MM everywhere.

Soap Shield is from gardens alive here is a link so you can read about it http://www.gardensalive.com/product.asp?pn=8066

When using the baking soda, is there any problem with altering the ph of the soil or the plants? I read somewhere that you have to be careful with that, but I've also read here that many people use it regularly.

ksbmom wrote:When using the baking soda, is there any problem with altering the ph of the soil or the plants? I read somewhere that you have to be careful with that, but I've also read here that many people use it regularly.

I use it as a foliar treatment only so there should be no problem with potentially changing the pH of the growing mix.