Phytophthora blight (Phytophthora capsici)
All parts of the pepper plant can be affected. Seedlings can be killed. Collar rot and wilt phase is most common and is characterised by a dark brown stem discolouration extending upward from the soil line accompanied by a sudden wilt of the entire plant. Upper stem lesions (spots) are also dark brown and occur primarily at branch points causing death of branches above the lesions. Leaf spots are round or irregularly shaped, dark green and water-soaked. They later dry and become light tan.
Fruit infection begins as water-soaked, dull green spots that expand rapidly to cover the entire fruit. Later the fruits become flaccid and wrinkled but do not detach from the affected plants. The host range of the fungus includes cucurbits, eggplants and tomatoes. The fungus can survive on and in seeds, in soil and in crop debris. The collar rot and wilt phase is most severe in over-irrigated or poorly drained fields. Aboveground infection is associated with extended periods of rainfall or overhead irrigation.
- Plant resistant cultivars, if available.
- Use certified disease-free seeds.
- Grow on elevated beds.
- Practise good water management.
- Practise crop rotation (avoid in the rotation crops such as cucurbits, eggplant and tomatoes).
- Remove and destroy crop debris after harvest.
- Copper sprays can minimise disease losses.