Re: [tomato] Late Blight

margaret lauterbach (
Wed, 07 Jul 1999 10:50:55 -0600

At 07:11 AM 7/7/99 -0700, you wrote:
>I have talked with some people up in the Vancouver B.C., area and they have
>claimed to not have grown a ripe tomato in the last 10 years because of a
>late blight that comes in and rots all the tomatoes before they can ripen.
>This particular person is a Mycologist and he has been frustrated about that
>situation for a long time.  Because that has been going on for so long, I
>suspect they have not been able to find any solution for that blight
>situation.  It's a highly populated area.  Is anyone on this list familiar
>with this particular blight?

Late blight is the cause of the Irish potato crop failures that resulted in
so many starvations. It is transmissible, back and forth between potatoes
and tomatoes. There are sprays for late blight on potatoes available to
farmers, but I don't know whether there are any for tomatoes. It is common
in damp/rainy/humid areas, so we seldom see it in Idaho. But two or three
years ago some tomatoes were so afflicted and a few potatoes were
identified as having it. That triggered a lot of costly spraying, but
potato prices didn't keep up.  Early and late blight are different blights.
Early may occur late, and late occur early. 

It is very common in Seattle, and a lot of people have complained about it.
Travis Saling grows tomatoes in plastic tunnels, or cloches, as he calls
them, and does pick ripe tomatoes. I think the blight, like most fungal
diseases, is spread by splashing water, whether it's wind-blown rain or
water splashing upward from the soil. A good mulch layer is effective in
preventing fungi from the splashing upward. Margaret