First, there are two types of blight. Early Blight and Late Blight. Phytophthora infestans (aka "Late Blight"). It is not a bacteria or a virus, but rather are a "fungus" caused by infectious spores from standing water that is stagnant on the plants. Early Blight, is caused by a different fungus and occurs in more arid regions. Regardless, the outcome is the same, leaf and stem legions and fruit rot. Blight can occur at any time. I think that what we are seeing here is a Late Blight. Temperature, humidity, and rainfall are the players in this disease. Additionally, blights can spread to other plants from wind blown rain and running ground water. Blight needs a living organism to survive. So keep this in mind for our mild winters and potential un-rotted organic material in the soil. This combination can facilitate another blight outbreak for the next growing season.
So how do we prevent this problem? I've read a variety of suggestions and will list them here.
- Don't plant tomatoes in the same location next year. (I've read keep them away from the soil for 4 seasons)
- Use a drip irrigation vs hose watering to reduce splash on leaves.
- Raised beds and well spaced so they are not touching
- Remove any leaves or stems that are showing the blight
- Apply a fungicide
Anyway, these are all lessons learned for me. Hopefully this information will benefit those other garden aficionados that read this. If anyone has other insightful information on tomato blight, please share!