Check the ground around the plants for excess water, either from runoff or poor drainage. Press your hand into the soil. If it doesn't spring back, but rather leaves a pool of moisture, it is too wet in the area.
Create a barrier to reroute water if you have a runoff issue. Use landscape material such as bricks or stones to force water into a new direction, or dig a shallow trench to route the water away from the plants.
Dig out some of the soaked soil and incorporate fresh soil in its place to dry out the area.
Water the plants in the early morning to help sustain them through the hot hours of the day.
Add water in the early evening if the plants have wilted. Do not add too much water in the evenings because the dark hours of the night along with wet conditions create conditions for mildew and mold growth.
Dig a shallow trench in a ring around the plants to trap water runoff and keep it close by as an additional source of water.
Remove plants affected by the fungal disease. Pull them plants up and put in a plastic bag for disposal.
Spray a disinfectant on the soil in the area where the infected plants were growing. Look for a chemical spray that contains dazomet, metamsodium, chloropicrin or formaldehyde. This may or may not kill the fungi in the soil because the spray only penetrates so far down. For added protection, wait a few days, and till the soil manually so as not to create dust that might blow over on other plants. Respray the area.
Disinfect any tools, pots or other garden objects that came in contact with the diseased plants with a bleach solution.