Late Blight of Tomato

Late Blight of TomatoLate Blight Tomato Close Up

Late blight of tomato has attacked my tomatoes!  It was before the first frost of the season so  I collected all the green tomatoes from my garden. I was hoping to extend the season by letting them ripen in the house.  I had a nice batch of tomatoes and was looking forward to enjoying them in the beginning of winter.  Some of them were big, fat and gorgeous but just not red.

Late Blight is REALLY UGLY

My beautiful green tomatoes started turning leathery, brown and bumpy.  I couldn’t really believe my eyes that this was happening and I had no idea what it was.

I started checking on the internet and saw that it was probably late blight.  I have been struggling with early blight the last few years.  This year I had good successes against early blight and now this!!  The diseases are not related at all.  I checked with the Extension service and this is the response that I got:More Late Blight Tomato

 

Our plant pathologist looked at your photos and thinks this is Late Blight. Sometimes found in Maryland and affecting both potatoes and tomatoes, it is the fungal pathogen responsible for the infamous Irish potato famine. It can be a very serious disease when the weather is consistantly cool and rainy, which makes it more likely to occur at the end of the growing season.

Chances of the disease overwintering are not great. However, it can overwinter on potato tubers left in the ground of diseased plants. It is recommended to do a thorough end of season clean-up in your garden.  Do not compost any plant parts or fruits; get them out of the yard completely.

Here is our page about Late Blight from the Plant Diagnostic portion of our website: http://plantdiagnostics.umd.edu/level3.cfm?causeID=1381

I read that late blight is an airborne disease.  This all happened after Hurricane Sandy.  So the weather was cool and rainy with lots of wind–I wonder if it blew in with the hurricane.  Also not all of the green tomatoes got it.  I did get a few that ripened beautifully and were delicious. Here is late blight information from Cornell University supporting this idea:

Note that during cloudy conditions spores of the late blight pathogen can survive being dispersed in wind currents long distances (miles!) because they are protected from the killing effects of UV radiation. Rain can bring these spores down on to plants far from the affected plants that were their source.