Here’s a comprehensive, detailed overview of major vegetable diseases, organized by pathogen type and including key symptoms, host crops, conditions, and control methods:
🦠 1. Fungal & Oomycete Diseases
Disease | Pathogen | Hosts | Symptoms | Conditions | Control |
---|---|---|---|---|---|
Early Blight | Alternaria solani | Tomato, potato | Concentric brown leaf spots, fruit lesions | Warm, wet | Rotate crops, chlorothalonil, copper en.wikipedia.org+13extension.umd.edu+13agrilife.org+13southernliving.com+1en.wikipedia.org+1 |
Late Blight | Phytophthora infestans | Tomato, potato | Water-soaked leaves/fruit, white sporulation | Cool, humid | Remove debris, fungicides |
Powdery Mildew | Erysiphe, Podosphaera spp. | Squash, cucumber, tomato | White powder on leaves | Warm, high humidity | Sulfur, neem, drip irrigation |
Downy Mildew | Peronospora, Pseudoperonospora spp. | Cucumber, spinach | Angular chlorotic spots, underside fuzz | Cool, wet | Metalaxyl, copper |
Anthracnose | Colletotrichum spp. | Bean, cucumber, melon, tomato | Sunken fruit/leaf lesions | Warm, wet | Copper, pruning |
Gummy Stem Blight | Didymella bryoniae | Cantaloupe, cucumber | Stem lesions, pycnidia, leaf blight | Warm, humid | Fungicides, remove crop residue |
Southern Blight | Athelia/Sclerotium rolfsii | Pepper, bean, carrot | Stem rot, white fan, sclerotia | Warm, moist | Soil solarization, fungicide |
White Mold (Sclerotinia) | S. sclerotiorum | Bean, lettuce, cucumber | White mycelium, sclerotia, collapse | Cool, moist | Crop rotation, clean debris |
Phytophthora Blight | P. capsici | Tomato, pepper, squash | Crown rot, root rot, fruit blight | Water-logged, warm | Good drainage, fungicides |
🧫 2. Bacterial Diseases
Disease | Bacterium | Hosts | Symptoms | Conditions | Control |
---|---|---|---|---|---|
Bacterial Leaf Spot | Xanthomonas campestris | Brassicas, tomato, pepper | Angular spots, yellow halos, stem cankers | Rain/wind splash | Remove debris, copper sprays en.wikipedia.org+12en.wikipedia.org+12en.wikipedia.org+12vegpath.plantpath.wisc.edu+6agriculture.vic.gov.au+6extension.uga.edu+6 |
Bacterial Speck/Spot | Pseudomonas syringae/Xanthomonas | Tomato, pepper | Tiny dark spots on leaves/fruit | Cool, wet | Copper sprays, resistant varieties |
Bacterial Wilt | Ralstonia solanacearum | Tomato, pepper, eggplant | Sudden wilting, no leaf yellowing | Warm soil, insect vectors | Clean transplants, rotate crops |
Black Rot (Brassicas) | X. campestris pv. campestris | Cabbage, broccoli | V-shaped lesions, blackened veins | Warm, rainy | Seed-free stock, copper treatment |
Bacterial Soft Rot | Erwinia carotovora | Carrot, cabbage, potato | Soft mushy root/fruit, foul smell | Waterlogged soil | Improved drainage, sanitation |
🌱 3. Viral Diseases
Disease | Virus Type | Hosts | Symptoms | Transmission | Control |
---|---|---|---|---|---|
Cucumber Mosaic Virus | CMV (virus) | Cucumber, pepper, tomato | Mosaic, distortion, stunting | Aphids, seeds | Resistant seeds, vector control extension.umd.edu+13en.wikipedia.org+13southernliving.com+13 |
Tomato Mosaic Virus | Tobamovirus | Tomato, pepper | Mosaic, leaf distortion | Seed, tools, contact | Clean tools, resist varieties |
Tomato Spotted Wilt Virus | Tospovirus | Tomato, pepper | Necrotic rings, wilting | Thrips | Insect controls, resistant varieties |
Lettuce Mosaic Virus | Potyvirus | Lettuce, spinach | Mosaic, poor head development | Aphids, seed | Certified seed, rogue infected plants |
Tomato Yellow Leaf Curl Virus | Begomovirus | Tomato | Curling/yellowing leaves, stunting | Whiteflies | Reflective mulch, resistant cultivars |
🐛 4. Soilborne & Nematode Pests
Pest/Disease | Agent | Hosts | Symptoms | Control |
---|---|---|---|---|
Root-Knot Nematode | Meloidogyne spp. | Many vegetables | Root galls, stunting, wilting | Nematicides, rotation bhg.com+3thespruce.com+3extension.uga.edu+3gardeningknowhow.com+8agrilife.org+8en.wikipedia.org+8 |
Colletotrichum Root Rot | Phytophthora spp. | Many crops | Root rot, damping-off | Drainage, fungicides |
🌾 5. Abiotic & Nutrient Disorders
Disorder | Cause | Hosts | Symptoms | Remedy |
---|---|---|---|---|
Blossom-End Rot | Ca deficiency + uneven moisture | Tomato, pepper, squash | Sunken brown rots on fruit | Ca sprays, consistent watering en.wikipedia.org+2thespruce.com+2bhg.com+2agrilife.orgen.wikipedia.org+4ag.purdue.edu+4agrilife.org+4 |
Sunscald | Excess sun exposure | Tomato, pepper | White/bleached patches | Shade, avoid leaf pruning |
Tipburn | Calcium deficiency in heads | Lettuce | Inner leaf browning | Calcium foliar sprays |
✅ Recommended Management Practices
Rotate crops, use disease-resistant varieties
Ensure proper drainage; prevent water logging
Use certified seed and transplants
Apply fungicides/bactericides only when needed
Control vectors (aphids, thrips, whiteflies)
Maintain field hygiene and remove crop debris
Monitor regularly and scout early for symptoms