| { |
| "schema_version": "1.0.0", |
| "disease_id": "mango.unknown.dieback", |
| "aliases": [ |
| "Tip dieback", |
| "Twig blight", |
| "Gummosis" |
| ], |
| "crop": { |
| "common_name": "mango", |
| "scientific_name": "Mangifera indica", |
| "family": "Anacardiaceae" |
| }, |
| "condition": { |
| "common_name": "dieback", |
| "scientific_name": "", |
| "alt_names": [ |
| "Twig dieback", |
| "Branch dieback", |
| "Tip necrosis" |
| ], |
| "pathogen": { |
| "type": "unknown", |
| "taxonomy": { |
| "kingdom": "", |
| "phylum": "", |
| "class": "", |
| "order": "", |
| "family": "", |
| "genus": "", |
| "species": "" |
| } |
| } |
| }, |
| "issue_type": "unknown", |
| "transmission": { |
| "vectors": [ |
| "Pruning tools", |
| "Insects (borers)" |
| ], |
| "dispersal": [ |
| "Wind-driven rain", |
| "Contaminated pruning tools", |
| "Infected planting material" |
| ], |
| "overwintering": [ |
| "Infected dead twigs", |
| "Cankers on branches", |
| "Plant debris" |
| ] |
| }, |
| "environmental_risk": { |
| "risk_factors": [ |
| "High humidity", |
| "Prolonged rainy season", |
| "Wounds from pruning or insects", |
| "Poorly drained soils", |
| "Nutrient deficiency (e.g., copper)", |
| "Post-harvest stress" |
| ], |
| "temp_c_day": [ |
| 25, |
| 35 |
| ], |
| "temp_c_night": [], |
| "relative_humidity_pct": [ |
| 80, |
| 100 |
| ], |
| "leaf_wetness_hours_threshold": 12 |
| }, |
| "severity_rubric": { |
| "unit": "qualitative", |
| "mild": "One or a few small terminal twigs show dieback, affecting <10% of the canopy.", |
| "moderate": "Multiple branches show dieback, progressing downwards, affecting 10-30% of the canopy.", |
| "severe": "Major limbs or the main trunk are affected, with significant canopy loss >30% and potential tree death.", |
| "notes": "Severity is measured by the percentage of the tree's canopy showing dead or dying branches, starting from the tips and progressing inwards." |
| }, |
| "symptoms": { |
| "leaves": [ |
| "Wilting and drooping of leaves on affected twigs.", |
| "Leaves turn brown or black, but remain attached to the dead branch for some time.", |
| "Young leaves at the tip of a branch suddenly dry out and appear scorched." |
| ], |
| "stems": [ |
| "Progressive drying of twigs and branches from the tip downwards.", |
| "Affected bark turns dark brown to black.", |
| "A distinct dark, sunken band may be visible at the junction of healthy and diseased tissue.", |
| "Gum or a dark, sticky substance may exude from cracks in the bark (gummosis).", |
| "Small, black, pin-head sized fruiting bodies (pycnidia) may appear on dead twigs under moist conditions." |
| ], |
| "fruit": [ |
| "Fruit on affected branches may shrivel, mummify, and remain attached." |
| ], |
| "roots": [], |
| "whole_plant": [ |
| "Affected branches appear barren and dead against the healthy foliage.", |
| "In severe cases, the entire tree may die." |
| ], |
| "signs_microscopic_or_visible": [ |
| "Black, pimple-like structures (pycnidia) embedded in the dead bark.", |
| "Oozing of dark, resinous gum from cankers on stems or branches." |
| ] |
| }, |
| "lookalikes": [ |
| { |
| "condition_name": "anthracnose", |
| "condition_id": "mango.fungal.anthracnose", |
| "key_differences": [ |
| "Anthracnose also causes distinct, dark, angular spots on leaves and sunken black lesions on fruit, which are not primary symptoms of dieback.", |
| "Anthracnose leaf spots often have a 'shot-hole' appearance as the center falls out.", |
| "Dieback is a progressive death from the tip, while anthracnose twig blight can appear as discrete cankers anywhere on the stem." |
| ] |
| }, |
| { |
| "condition_name": "senescence_or_dry", |
| "condition_id": "mango.abiotic.senescence_or_dry", |
| "key_differences": [ |
| "Drought stress causes a more uniform yellowing and drying of leaves across the whole plant, not just starting from the tips of specific branches.", |
| "Dieback often shows a clear demarcation line between dead and living tissue, which is less common in general drying.", |
| "There is no gummosis or presence of fungal fruiting bodies with simple drought stress or senescence." |
| ] |
| }, |
| { |
| "condition_name": "bacterial_canker", |
| "condition_id": "mango.bacterial.bacterial_canker", |
| "key_differences": [ |
| "Bacterial canker lesions are often water-soaked initially and may exude a lighter-colored bacterial ooze, unlike the dark gum of fungal dieback.", |
| "Bacterial canker also causes distinct, angular, raised, black spots on leaves and fruit.", |
| "While both can cause branch death, bacterial cankers can form anywhere on a stem, whereas dieback characteristically progresses from the tip downwards." |
| ] |
| } |
| ], |
| "management": { |
| "cultural": [ |
| "Prune and destroy affected twigs and branches, cutting at least 15-20 cm into the healthy wood.", |
| "Ensure proper irrigation and balanced nutrition to maintain tree vigor.", |
| "Avoid wounding trees during cultural operations.", |
| "Sterilize pruning tools (e.g., with 10% bleach solution or alcohol) between cuts and between trees." |
| ], |
| "biological": [], |
| "chemical": [ |
| "Apply protective copper-based fungicides (e.g., copper oxychloride, Bordeaux mixture) before the rainy season to protect from new infections.", |
| "After pruning, apply a fungicidal paste to the cut ends to prevent pathogen entry." |
| ], |
| "notes": "Integrated management focusing on sanitation and maintaining tree health is crucial. The exact chemical control depends on the specific pathogen identified." |
| } |
| } |
