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Originally Posted by tjg911
i see in the links provided by blueaussie that the LB for tomatoes is not the same as for potatoes. i guess this is why the volunteer potato plants from missed potatoes from the 2008 season are not infected when the tomatoes growing next to them are.
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I don't know if that's quite true, Tom. This strain of Late Blight may be affecting tomatoes more severely than potatoes, but that doesn't mean the potatoes can't get it too. Actually they are getting it, because I've seen it on potatoes here locally and I've heard a report or two of potato fields being mowed because the plants were too badly infected with Late Blight to have any hope of getting it under control.
It could be that your potatoes are a variety that have some tolerance to Late Blight so that it's taking longer to affect them. What kind are they?
Volunteer potato plants coming up from the previous season are one way that Late Blight is thought to be carried over from one season to the next. Check the Cornell Late Blight Factsheet again:
http://plantclinic.cornell.edu/FactS...light/late.htm
If this year's crop of potato tubers become infected by Late Blight spores being washed down onto them through the soil, and those tubers don't get killed by freezing over the winter, any spores or fungal growth on them will also survive the winter. Then the volunteer potato plants that grow from those infected tubers next spring will spread the infection to all your other potatoes and your tomatoes next year.