Common Plant Diseases & Pathogens
The key to combating diseases and pathogens is usually the same for most.
- Promote good air circulation.
- Rotate crops.
- Remove and destroy infected plants.
- Disinfect tools
- Use natural sprays.
|Ornamental plants, Vegetables, Fruit trees.||Black and brown spots on leaves that develop into rings. Leaves may die. Fruits and tubers develop dark sunken spots.||Proper seed selection. Dispose of infected crop. Promote good air circulation.|
|Anthracnose||Tomatoes, cucumbers, melons and beans are most affected.||Black sunken spots that may ooze pink slime.||Rotate crops, remove infected plants.|
|Bacterial Blight||Mostly Legumes.||Leafs and pods have water soaked spots that may ooze.||Remove and dispose of infected. Rotate crops.|
|Blackspot||Common on roses.||Spots on leaves with yellow margins. Leaf drop occurs||Destroy all affected parts. Mulch. Spray.|
|Club Root||Vegetables and flowers in the cabbage family.||Wilt during heat of day. Roots are distorted and swollen.|
|Cytospora Canker||Stone fruit and other tree species.||Discolored, circular spots on bark.||Cut out trees and branches with spots.|
|Damping-off||Many seeds.||Seeds rot before they germinate or seedlings rot and fall over.||Keep soil moist not waterlogged. Provide good air circulation. Sterile seed starting mix.|
|Downy Mildew||Many fruits, vegetables, flowers and grasses.||White to purple, downy growth, usually on th undersides of leaves and stems. Upper leaf surfaces have pale color.||Rotate crops. Remove infected plants.|
|Fire Blight||Fruit trees, roses and other small fruits.||Wilted shoots.||Promote good air circulation. Remove infected. Spray.|
|Fusarium, Verticillium wilt||Wide range of flowers, fruits, and ornamentals.||Wilt and yellowing.||Rotate crops. Destroy infected branches or plants.|
|Galls||Grapes, roses, fruit trees, brambles, flowers, vegetables.||Swollen masses of abnormal tissue.||Disinfect tools between pruning. Remove infected plants.|
|Phytophthora Blight (Late Blight)||Lilacs, Rhododendron, Azalea, Holly, Pepper, Potato, Tomato.||Shoot dieback and cankers on stems. Dark spots on tubers.||Prune infected branches to increase air movement and remove infected parts. Keep area as dry as possible.|
|Leaf Blisters, Curls||Fruit trees and other tree species.||Distorted, curled leaves. Yellow bumps, leaf curl. Damaged fruit, may kill tree.||Oil spray.|
|Leaf spots||Many species.||Many fungi can cause spots. They can grow together to become blight or blotch.||Preventive sprays.|
|Molds||Fruits, flowers, vegetables.||Powdery or woolly appearance on the surface.||Destroy infected and dead materials. Prune and allow space for good air movement.|
|Nectria Canker||Hardwoods, some vines and shrubs.||Wounds appear on bark. Pink spore producing structures starts to form.||Limit pruning cuts, and remove diseased branches.|
|Nematodes||Everything||Reduced growth, wilting, and vigor. Rotted roots, lumps on roots or dead leaves.||High organic matter in soil. Rotate crops.|
|Powdery Mildew||Very common||White powdery growth on surface of leaves. Black dots appear and produce spores. Premature fruit ripening.||Improve air circulation. Dispose of infected plants. Spray.|
|Rusts||Many species.||Powdery tan to rust colored coating.||Apply neem. Space plants correctly to allow air flow. Burn infected plants.|
|Scabs||Fruit trees and other tree species.||Fruit, leave, tubers hardened, overgrow or crack.||Dispose of fallen leaves and prune to increase air movement.|
|Smuts||Grasses, grains, and corn.||Enlarged galls to a powdery mass as they age.||Remove infected parts and rotate crops.|
|Stewart’s Wilt||Mostly sweet corn.||Leaves wilt, slime may ooze out of stalks.||Eliminate flea beetles (host). Destroy infected plants.|