Here’s a comprehensive and detailed list of all major root diseases affecting plants, including causal agents, symptoms, host plants, conditions favoring the disease, and treatment options. The diseases are categorized based on their etiology: fungal, bacterial, nematodal, viral (rare), physiological, and nutrient-related.
🦠 I. Fungal Root Diseases
Disease Name | Pathogen (Latin) | Host Plants | Symptoms | Conditions | Severity | Treatment |
---|---|---|---|---|---|---|
Phytophthora Root Rot | Phytophthora spp. | Avocado, citrus, durian, peppers | Dark brown to black root rot, stem cankers, leaf wilt | Poor drainage, warm & wet | High | Metalaxyl, Fosetyl-Al |
Fusarium Root Rot | Fusarium solani, F. oxysporum | Tomato, beans, cucurbits | Brown streaks on roots, yellowing leaves, plant stunting | High temperature, acidic soils | Medium–High | Carbendazim, crop rotation |
Pythium Root Rot | Pythium spp. | Lettuce, spinach, seedlings | Water-soaked roots, damping off | High moisture, low oxygen | High in seedlings | Propamocarb, disinfection |
Rhizoctonia Root Rot | Rhizoctonia solani | Rice, potatoes, vegetables | Brown sunken lesions on roots and collars | Warm, moist soil | Medium | PCNB, soil solarization |
Armillaria Root Rot | Armillaria mellea | Woody perennials | White mycelium under bark, root decay | Forest soils, poorly drained areas | Chronic | None effective; remove stump |
🧫 II. Bacterial Root Diseases
Disease Name | Pathogen | Host Plants | Symptoms | Conditions | Treatment |
---|---|---|---|---|---|
Crown Gall | Agrobacterium tumefaciens | Grapes, roses, stone fruits | Tumorous galls at root crown | Wounded roots | Sanitation, resistant rootstocks |
Bacterial Root Rot | Erwinia carotovora | Carrot, onion, ornamental bulbs | Soft mushy roots, foul odor | Waterlogged soils | Streptomycin (limited use), drainage |
🐛 III. Nematode-Related Root Diseases
Disease Name | Nematode Species | Host Plants | Symptoms | Type | Control |
---|---|---|---|---|---|
Root Knot Nematode | Meloidogyne spp. | Tomato, okra, cucurbits | Root galls, stunting | Endoparasitic | Abamectin, solarization, resistant varieties |
Lesion Nematode | Pratylenchus spp. | Bananas, cereals | Lesions, browning, poor root hairs | Migratory endoparasite | Crop rotation, organic amendments |
Stubby Root Nematode | Trichodorus spp. | Corn, potatoes | Short, stubby roots | Ectoparasite | Fumigation, soil organic matter |
🧬 IV. Viral Root Diseases (Rare, usually secondary)
Disease Name | Virus | Host Plants | Root Symptoms | Transmission |
---|---|---|---|---|
Banana Bunchy Top Virus (BBTV) | BBTV (DNA, non-enveloped) | Banana | Root decay (secondary to top death) | Aphids |
Cassava Mosaic Disease | Geminiviruses | Cassava | Weak roots (indirect) | Whitefly |
📌 Viral root symptoms are usually secondary due to systemic plant decline rather than direct infection of root tissues.
🌱 V. Root Disorders Due to Environmental Stress
Name | Cause | Host Plants | Symptoms | Solution |
---|---|---|---|---|
Root Asphyxiation | Waterlogging | Most crops | Blackened roots, wilting | Improve drainage, raised beds |
Salt Damage | High salinity (Na⁺, Cl⁻) | Rice, onions | Root tip burn, poor absorption | Leaching, gypsum, tolerant varieties |
Soil Compaction | High bulk density | Maize, wheat | Limited root depth | Tillage, organic matter |
🥕 VI. Nutrient Deficiency-Related Root Disorders
Deficient Nutrient | Root Effect | Host Plants | Visual Symptoms | Correction |
---|---|---|---|---|
Phosphorus (P) | Poor root branching | All vegetables | Purplish leaves, weak root system | Rock phosphate, DAP |
Calcium (Ca) | Weak cell walls | Tomato, strawberry | Brittle roots, blossom end rot | Lime, CaNO₃ |
Nitrogen (N) | Shallow root mass | Leafy greens | Pale leaves, stunted roots | Urea, compost |
Iron (Fe) | Chlorosis affects root metabolism | Citrus, soybean | Interveinal chlorosis | Fe-chelates |
Zinc (Zn) | Stunted primary root | Corn, beans | Leaf bronzing, reduced root tips | ZnSO₄ foliar spray |
🧪 VII. Root Cancer and Neoplastic Disorders
Condition | Cause | Host | Symptoms | Treatment |
---|---|---|---|---|
Crown Gall (tumor-like) | Agrobacterium tumefaciens | Fruit trees, grapes | Large root galls | None curative |
Root Hyperplasia (due to hormone imbalance) | Mutation or pathogens | Orchids, tubers | Root overgrowth | Pruning |
📊 Summary by Disease Type and Control Difficulty
Disease Type | Frequency | Severity | Ease of Control | Key Strategy |
---|---|---|---|---|
Fungal | Very Common | High | Moderate | Fungicides + drainage |
Bacterial | Moderate | Medium | Moderate | Hygiene + resistant rootstocks |
Nematodes | Common | Moderate–High | Difficult | Rotation + nematicides |
Nutrient Issues | Common | Low–Medium | Easy | Balanced fertilization |
Environmental | Widespread | High if unmanaged | Varies | Cultural practices |
Viral | Rare (for roots) | Indirectly Severe | Hard | Vector control |
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