Comprehensive and detailed catalog of major leaf diseases

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Below is a comprehensive and detailed catalog of major leaf diseases, categorized by pathogen type—fungal, bacterial, viral, parasitic, physiological, and nutrient-related. For each disease, you’ll find the name, causal agent, host plants, symptoms, conditions favoring the disease, host age, seasonality, potential impact, and treatment or prevention methods.


🍄 I. Fungal Leaf Diseases

Disease Name (EN)Latin PathogenHost PlantsSymptomsFavorable ConditionsAge AffectedSeasonImpact SeverityTreatment/Control
Leaf BlightAlternaria spp.Cabbage, tomato, onionDark concentric rings on leavesWarm, humidAllSummerMediumMancozeb, improve airflow
Leaf SpotCercospora spp.Sugar beet, soybean, riceSmall circular spots with halosWet weatherAllRainy seasonMedium–HighChlorothalonil, crop rotation
Powdery MildewErysiphe sp., Oidium sp.Grapevine, pumpkin, roseWhite powder, yellowing leavesHigh humidity, low wetnessAllLate summerMediumSulfur, potassium bicarbonate
Downy MildewPeronospora sp., Plasmopara sp.Grapes, lettuce, maizeGray fuzz, chlorotic patchesCool nights, dewAllSpring–SummerHighMetalaxyl, copper fungicides
AnthracnoseColletotrichum spp.Mango, beans, tomatoSunken lesions, fruit involvedRainy, leaf wetnessFruit treesOnset of rainsMedium–HighAzoxystrobin, avoid overhead watering
Septoria Leaf SpotSeptoria lycopersiciTomatoSmall black spots, yellow haloCool, persistent wetnessMature plantsEarly wet seasonMediumCopper sprays, straw mulch
RustPuccinia spp., Uromyces spp.Wheat, soybean, beansOrange/brown pustules on lower leavesWarm, dampAllSummerMedium–HighSulphur, resistant cultivars
Leaf RustMelampsora spp.Poplar, willowOrange pustules, defoliationCool spring, wetTrees/shrubsSpringMediumFungicide, resistant clones

🧫 II. Bacterial Leaf Diseases

Disease NameLatin PathogenHostsSymptomsConditionsSeasonImpactTreatment
Bacterial Leaf SpotXanthomonas spp.Pepper, tomato, riceWater-soaked lesions, yellow haloRain splash, warm daysSummerMediumCopper oxychloride, hot water seed treatment
Bacterial BlightPseudomonas syringae pathovarsBeans, cucurbitsAngular necrotic spots, water-soakingCool, wet periodsSpring–FallLow–MediumCopper + streptomycin, pathogen-free seed
Bacterial Leaf ScorchXylella fastidiosaAlmond, oak, plumScorched leaf margins, declineWarm, vector-borneSummerMediumXylem flush, leaf removal
Bacterial Wet LeafErwinia amylovoraApple, pearOoze, browning blossoms/leavesWarm wet weatherSpringMediumStreptomycin, sanitizer sprays

🌱 III. Viral Leaf Diseases

DiseaseLatin PathogenHostsSymptomsTransmissionSeasonImpactControl
Mosaic VirusTMV, CMV, etc.Cucumber, tobacco, squashMosaic patterns, distorted leavesInsects, seed, sapYear-roundHighResistant varieties, insect control
Leaf CurlTaphrina deformansAlmond, peachCurled, thickened, pinkish leavesMoist cool springSpringMediumCurative copper sprays
Yellow MosaicPotyvirus spp.Bean, soybeanYellow mosaic streaksAphid vectorsEarly summerMediumInsecticides, resistant seeds

🐛 IV. Parasitic and Infestation-Related Leaf Damage

IssueParasiteHostsSymptomsSeasonControl
Leaf GallMeloidogyne spp. (nematode)Oak, hickory, grapevineGalls on leaves, twisted growthGrowing seasonAcaricides, root nematicides
Leaf MinerLiriomyza sp.Tomato, cucurbitsSerpentine mines, feeding damageSummerInsecticides, pheromone traps
Scale Insect DamageCoccoidea familyCitrus, ornamentalsYellowing leaves, sticky honeydewAll seasonsOils, systemic insecticides

🌊 V. Physiological Leaf Disorders

ConditionCauseHostsSymptomsSeasonRemedy
Sunburn/Leaf ScorchUV & heatOrchards, ornamentalsBleached blotches, crisp edgesSummerShade cloth, whitewash
Herbicide InjuryChemical driftMany cropsDistorted, crinkled, bleached leavesApplication periodsBuffer zones, spray formulator

🥦 VI. Nutrient Deficiency Leaf Symptoms

NutrientLeaf AppearanceAffected PlantsSolution
Nitrogen (N)Uniform pale green/yellow leavesCorn, leafy vegetablesApply urea or ammonium sulfate
Magnesium (Mg)Interveinal chlorosisCitrus, potatoesApply magnesium sulfate
Iron (Fe)Interveinal yellowing on young leavesCitrus, blueberryFoliar chelated iron
Calcium (Ca)Tip/edge necrosisTomatoes, strawberriesFoliar Ca sprays, consistent watering
Zinc (Zn)Rosetting, stunted leavesMaize, beansFoliar ZnO or ZnSO₄

📊 Disease Overview by Type

Disease TypeCommon ExamplesRisk LevelControl Strategy
FungalBlight, Mildews, RustMedium–HighFungicides, resistant varieties
BacterialSpot, Blight, ScorchMediumCopper agents, hygiene
ViralMosaic, CurlHighInsect control, resistant lines
ParasiticLeaf gall, MinerLow–MediumPesticides, cultural disruption
PhysiologicalSunburn, Drift injuryLowCultural controls
Nutrient deficiencyYellowing, chlorosisLowFertilization, soil management

🛠️ Management Recommendations

  1. Routine monitoring for early signs on leaves.

  2. Integrated treatment using chemical, biological, and cultural methods.

  3. Fungicide/ bactericide rotation to prevent resistance.

  4. Multispecies cropping and crop rotation to reduce pathogen buildup.

  5. Use of resistant cultivars and maintaining soil fertility for plant vigor.

  6. Proper irrigation practices—avoid overhead watering and excessive moisture.

  7. Quarantine practices for imports to avoid new pathogens.

 

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