I am seeing Tomato Wilt in various plots throughout the garden. With this heat, you may think that a plant is “having a bad day”. When you come back tomorrow, the plant will be dead. It hits that quickly. I pulled 2 plants in my plot on the far end earlier this week. I some at the back and front of the garden today too.
Please check your plot pull these plants asap. Put them in a plastic bag, tie and throw away. (Preferably take home to dispose of). These plants won’t survive and will just spread the disease throughout the entire garden.
There is no treatment for this disease besides sterilizing the soil.
Last season I lost all of my tomatoes, and eventually my entire plot was pulled and covered with black tarp to try to kill it off. A plant pathologist tested a plant pulled and said it was Southern Blight. It loves hot and humid and said it was very hard to combat. The recommendation was to not replant tomato.
You can read more about Southern Blight here.
Denise has some additional suggestions to prevent spread:
Because it is very contagious, space out your plants. Crowded plants will spread the disease quicker. You risk losing all plants.
When watering, do not splash up from the ground. You can water gently or with buckets, but no splashing.
Trim away bottom leaves to prevent the fungus from splashing up onto your plant.
Maintain spacing between plants for airflow and protection (can plant other stuff in between).
Do NOT replace a wilt victim with another tomato! Ideally, cover that soil with black plastic and leave in hot sun to sterilize.