My tomato plants have suddenly started to die from the botom up. first just the leaves ,but now all the tomatoes are developing a white rot from the stem. The zucchini squash leaves,that are growing next to the tomatoes are turning white,but the rest of the vegetables seem fine so far. Is there anyway to avoid this for next year? Something to do to the soil? We are baffled!!!
From the picture, it appears to be late blight. I would highly recommend that you take a sample into your local extension office to confirm. Late blight is a very fast moving fungal disease that can wipe out fields of tomatoes. If it is confirmed as late blight, in order to overwinter, it needs living tissue to survive in. A very, very thorough garden cleanup this fall should eliminate any bits of tomato plant. I have attached a link about late blight.
This fungal disease does not affect zucchini, but I suspect that what you may be seeing is powdery mildew. Most gardeners accept the fact that at some time during the season, this fungal disease will appear on the squash leaves. You can look for resistant varieties, keep plenty of space between plants, and/or try a fungicide - most gardeners report very little relief from the use of fungicides.
Your county extension office is at:
214 Donohoe Road, Suite E
Greensburg, PA 15601
Directions to our office