Sometimes, peppers wilt because they're baking in the hot sun, but it’s very likely they have fusarium or verticillium wilt. If your peppers are wilting suddenly, developing large yellow areas and drooping despite adequate watering, fungal wilt is probably to blame. Resistance to Verticillium wilt in commercial cultivars of peppers is not common and is difficult to identify in pepper germplasm. Fungal wilts are soil-borne and can live in the soil for many years. Long crop rotations may be able to kill the fusarium and verticillium pathogens, but it will take time before planting in the old location is safe again. Choose a new garden location and keep it free of fungus by increasing drainage and only watering when the top two inches of soil feel dry to the touch. Rotations with broccoli, corn, wheat, barley, or sorghum for a period of at least 2 years (the longer the rotation, the better) can reduce inoculum and subsequent plant infection. These crops are not hosts for the Verticillium pathogen, and populations of the pathogen will decline where host plants are not present. In severe cases, do not replant peppers in the same spot for a minimum of 3 years. I hope this helps.
