Disease in bell pepper plants can be devastating to the home gardener because many of these same issues can also affect other crops and ornamental plants, endangering both your garden yield and your landscaping. The Mississippi State University Extension advises that diseases of bell peppers can have parasitic and nonparasitic causes. Parasites include fungi, viruses, bacteria and nematodes. Nonparasitic causes are environmental conditions that lead to disease of the plant.
Bacterial Leaf Spot
According to the Mississippi State University Extension, Xanthomonas vesicatoria is responsible for circular spots of dead or dying tissue on bell peppers. These can occur on any part of the plant, but the undersides of the leaves are often where the first signs appear. These spots transition from yellow or green and water-soaked or oily to scabby- or warty-appearing raised brown patches. The affected leaves may drop from the plant. The disease spreads during warm and wet weather; gardeners should wait to work with their plants until they are dry to prevent the spread of the disease. To combat the problem, gardeners should buy resistant varieties or treated seed, or treat the plants with copper fungicide spray. Integrated Pest Management Centers suggest crop rotation --- not using the same location for members of the tomato or pepper family for two years or more. Gardeners should remove old plant material after the growing season, and be aware that multiple leaf spot diseases may infect plants at the same time.
Blossom-end rot is a nonparasitic disease that is followed by a secondary fungal infection that causes blossoms to rot. According to Integrated Pest Management Centers, the signs include an area water-soaked in appearance around the blossom, poor blossom development and a dark brown or black patch on the fruit. According to the University of Illinois Extension, calcium deficiency within the plant itself is what causes end rot, a condition not usually helped by the addition of calcium to the soil. The trouble begins when the plant's roots are damaged, or water is lacking. Gardeners should remove any pepper fruits with symptoms.
Southern blight is a fungal infection by Sclerotium rolfsii. Moist conditions and heat pair to help the fungus thrive in the Southern states. The infection is not isolated to peppers. This blight destroys the whole plant by girdling the main stem. Wilt and death follow. According to the Mississippi State University Extension, a white mat of fungus, filled with light-brown, seedlike sclerota and located at the base of the plant, is the hallmark of the disease. The fungus can be spread through infected soil, water, air and contact with infected material. To combat infection, gardeners should follow good crop rotation methods, and keep the area around pepper plants free of debris and leaves.
- Mississippi State University Extension: Control Pepper Disease
- Integrated Pest Management Centers: Crop Profile for Bell Peppers in Virginia
- University of Illinois Extension: Watch Your Garden Grow-- Peppers
- North Carolina State University, Plant Pathology Extension: Bacterial Spot of Pepper and Tomato
- Texas A&M University, Aggie Horticulture: Pepper
- Photo Credit baby Jalapeno chilli pepper plants in nature image by Elena Moiseeva from Fotolia.com
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