Tomato late blight

**N* S* <s*@earthlink.net>**

Late blight is rearing it's ugly head here in Michigan. How many of

you have been able to hold it off once it has attacked a tomato plant

in your garden. If so what

did you use? I have been treating my plants with OMRI listed

Actinovate (streptomyces lydicus) every couple of weeks. I'm now

treating weekly or after a rain. Also, I'm using a spreader sticker to

increase its efficacy. So far they show no sign of disease, including

early blight. Today I'm also testing Serenade on a couple of plants.

Powdery mildew hit my summer squash a couple of weeks ago, but the

Actinovate knocked it back and the plants look great and are producing.

Here's what Michigan State University recommends for homeowners to

defend against late blight. Chorothalonil is very toxic and I would

never think of using it

or recommending it.

Homeowners

• Chorothalonil: Apply fungicides that list chlorothalonil as the

active ingredient every 7 days

or as the label specifies.

• Copper-based products: Chlorothalonil can also be mixed with copper

fungicides (each at

the full labeled rate).

Organic Growers

Your local organic certifying agency can help you determine what

products are approved.

• Copper-based products: Some forms of copper hydroxide are approved

for use in organic

production.  Spray every 7 days or as the label specifies.

• Bacillus subtilis: Serenade, 4-8 lb every 5-7 days (0 days PHI).

Provides suppression.

Biological control product that needs-be applied before disease

development. Control may be

limited under heavy disease pressure.

• Other fungicides labeled for late blight that are OMRI-listed

include Sporatec, Sonata, and

OxiDate.

• NOTE: In general, products available to organic growers are not

likely to halt tomato late

blight when the environment favors disease (cool and wet).

Between rain and cold the tomato crop in Michigan was the worst ever

last year. A real disapointment for newbie gardeners.

I'm hoping to give them some safe tools that will enable them to

harvest some great tasting fruit. If they fail again this year

we may loose them for good.
Nancy
Nancy Szerlag
Columnist for Detroit News
szerlag@earthlink.net
Check blog at http://nancysgarden.wordpress.com

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