Fusarium Wilt

• A damaging disease of tomato and pepper plants is Fusarium wilt, which is caused by the fungus Fusarium oxysporum. This is a soil-borne fungus, which remains active in soil for a period of three years. The symptoms associated with Fusarium wilt in tomato plants include wilting of lower leaves, lower leaf death, stunting and plant death. Pepper plants are especially susceptible to the effects of this fungal disease. Dark cankers girdle the base of the plant, rotting it from the bottom up, followed by leaf wilt and death.
  
  

Verticillium Wilt

• Verticillium wilt produces symptoms strikingly similar to Fusarium wilt in pepper and tomato plants. This disease is caused by the fungus Verticillium albo-atrum and Verticillium dahliae. Tomato and pepper plants infected with Verticillium wilt begin to wilt at the base and the lower leaves die and drop off. Plants that survive for the season, usually produce low quality, small fruit and plants are stunted. Plants infected with Verticillium wilt have brown discoloration in the stem that moves upward into the plant.
  
  

Sclerotinia Stem Rot

• Sclerotinia stem rot is a common disease among greenhouse plants. This disease is caused by a soil-borne fungus. According to North Carolina State University, Sclerotinia stem rot is responsible for the death of approximately five to 10 vegetable bearing plants each year. The disease causing fungi lives up to seven years in dry soil. Sclerotinia stem rot affects tomatos, peppers, squash, cabbage, carrot, cucumber, beans and lettuce. The first symptoms of Sclerotinia stem rot is a white rot on lower leaves that touch the soil, which eventually girdle the entire plant. Black fruiting bodies develop on the stems of affected plants and a white fungal growth is present.
  
  

Herbicide Injury

• Herbicides are weed-killing chemicals that are often used on lawns and in greenhouses. Occasionally, herbicides injure plants and cause rotting at the bottom of the plants. Herbicides applied to lawns in close proximity can drift to areas where tomato and pepper plants are planted causing injury. Herbicide fumes are damaging to plants, as well. Pepper and tomato plants injured by chemicals often wilt at the base, especially if mulch laced with herbicides is placed beneath the plants. Other symptoms include stunting, wilting and deformation of fruit.