Tomato DiseasesTomato Diseases

FungalFungal

BacterialBacterial

ViralViral Cucumber Mosaic Virus

Bacterial Spot - Xanthomonas campestris pv. vesicatoria Bacterial Speck - Pseudomonas syringae pv. tomato

Fruit Anthracnose - Colletotrichum spp. Fusarium Wilt - Fusarium oxysporum Verticillium Wilt - Verticillium dahliae, V. albo-atrum Early Blight - Alternaria solani Late Blight - Phytophthora infestans Septoria Leaf Blight - Septoria lycopersici Soil Rot of Fruit - Rhizoctonia

Fusarium WiltFusarium Wilt

Fusarium WiltFusarium Wilt

Fusarium WiltFusarium Wilt

Verticillium WiltVerticillium Wilt

Tomato Diseases - Fusarium and Tomato Diseases - Fusarium and Verticillium Wilts - Verticillium Wilts - Key PointsKey Points

Pathogens: Pathogens: Fusarium oxysporum, Verticillium Fusarium oxysporum, Verticillium dahliae, V. albo-atrumdahliae, V. albo-atrum

Soil-borne pathogensSoil-borne pathogens Survive in soil for several yearsSurvive in soil for several years Plants generally infected through rootsPlants generally infected through roots

Tomato Diseases - Fusarium and Tomato Diseases - Fusarium and Verticillium Wilts - Verticillium Wilts - Control StrategiesControl Strategies

Rotation (at least 2-3 years)Rotation (at least 2-3 years) VF or VFN resistanceVF or VFN resistance

Septoria Leaf SpotSeptoria Leaf Spot

Septoria Leaf SpotSeptoria Leaf Spot

Tomato Diseases - Septoria Leaf BlightTomato Diseases - Septoria Leaf BlightKey PointsKey Points

Pathogen: Pathogen: Septoria lycopersiciSeptoria lycopersici Survives over winter on infected plant debris, and also on Survives over winter on infected plant debris, and also on

equipment, stakes and cagesequipment, stakes and cages Spores dispersed by splashing water (rain, irrigation), Spores dispersed by splashing water (rain, irrigation),

workers or equipment moving through wet plantsworkers or equipment moving through wet plants Favored by moist, warm weatherFavored by moist, warm weather Symptoms generally appear first on lower leavesSymptoms generally appear first on lower leaves

Tomato Diseases - Septoria Leaf BlightTomato Diseases - Septoria Leaf BlightControl StrategiesControl Strategies

Rotation (at least 1-2 years)Rotation (at least 1-2 years) Thorough sanitation of equipment, stakes, etc.Thorough sanitation of equipment, stakes, etc. Stake plantsStake plants Plastic mulchesPlastic mulches Fungicide spraysFungicide sprays

Several effective fungicides availableSeveral effective fungicides available Apply at least weekly when weather favorable for Apply at least weekly when weather favorable for

diseasedisease Good coverage, especially of lower leaves, crucialGood coverage, especially of lower leaves, crucial Carefully read label directionsCarefully read label directions

Early BlightEarly Blight

Early BlightEarly Blight

Early BlightEarly Blight

Tomato Diseases - Early BlightTomato Diseases - Early BlightKey PointsKey Points

Pathogen: Pathogen: Alternaria solaniAlternaria solani Survives on infected plant debris - partially buried debris is Survives on infected plant debris - partially buried debris is

an excellent source of inoculuman excellent source of inoculum Spores wind dispersed, can be carried long distancesSpores wind dispersed, can be carried long distances Greatest threat of infection:Greatest threat of infection:

Fields with short rotations Fields with short rotations Planting adjacent to fields infected previous year Planting adjacent to fields infected previous year

where debris not completely buriedwhere debris not completely buried Infection occurs first on oldest leavesInfection occurs first on oldest leaves

Tomato Diseases - Early BlightTomato Diseases - Early BlightControl StrategiesControl Strategies

Plant rotation - minimum of at least 2-3 years between Plant rotation - minimum of at least 2-3 years between solanaceous cropssolanaceous crops

Potato, tomato, weeds in nightshade family Potato, tomato, weeds in nightshade family excellent hostsexcellent hosts

Completely bury plant debris after harvestCompletely bury plant debris after harvest Fungicide applicationsFungicide applications

Several effective fungicides availableSeveral effective fungicides available Carefully read label directionsCarefully read label directions

Provide adequate nitrogenProvide adequate nitrogen Avoid excessive irrigationAvoid excessive irrigation

Late BlightLate Blight

Late BlightLate Blight

Tomato Diseases – Late BlightTomato Diseases – Late BlightKey PointsKey Points

Pathogen: Pathogen: Phytophthora infestansPhytophthora infestans Same fungus that causes late blight of potatoSame fungus that causes late blight of potato Isolates may differ in ability to infect potato and tomatoIsolates may differ in ability to infect potato and tomato Both mating types (A1 and A2) are now found in WIBoth mating types (A1 and A2) are now found in WI

Symptoms:Symptoms: Lesions on leaves initially water-soaked spots with irregular Lesions on leaves initially water-soaked spots with irregular

bordersbordersLesions turn pale green, then brown to almost blackLesions turn pale green, then brown to almost blackWhite fungal growth appears on underside of leaves at border White fungal growth appears on underside of leaves at border

between necrotic and healthy tissuebetween necrotic and healthy tissuePetiole and stem symptoms similar – lead to rapid death of plantPetiole and stem symptoms similar – lead to rapid death of plant

Tomato Diseases – Late BlightTomato Diseases – Late BlightKey PointsKey Points

Source of inoculum:Source of inoculum: Cull piles of infected potatoes or tomatoesCull piles of infected potatoes or tomatoes Infected tomato transplantsInfected tomato transplants Infected plants in neighboring fieldsInfected plants in neighboring fields Hairy nightshadeHairy nightshade

Favored by rain, high relative humidityFavored by rain, high relative humidity

Control StrategiesControl Strategies Destroy cull piles, and weed hostsDestroy cull piles, and weed hosts Plant disease-free tomato transplantsPlant disease-free tomato transplants Protectant fungicides – several effective fungicides availableProtectant fungicides – several effective fungicides available

Fruit AnthracnoseFruit Anthracnose

Fruit AnthracnoseFruit Anthracnose

Tomato Diseases - Fruit AnthracnoseTomato Diseases - Fruit AnthracnoseKey PointsKey Points

Pathogen: Several species including Pathogen: Several species including Colletotrichum Colletotrichum coccodes, C. dematiumcoccodes, C. dematium and and C. gloeosporioidesC. gloeosporioides

Favored by wet weather and warm temperaturesFavored by wet weather and warm temperatures Survives in soil and plant debris several yearsSurvives in soil and plant debris several years Spores splashed by rain or irrigation onto foliage and Spores splashed by rain or irrigation onto foliage and

fruitfruit Ripe or overripe fruit most susceptible, symptoms Ripe or overripe fruit most susceptible, symptoms

progress rapidlyprogress rapidly

Tomato Diseases - Fruit AnthracnoseTomato Diseases - Fruit AnthracnoseControl StrategiesControl Strategies

Rotation (at least 2 years)Rotation (at least 2 years) Weed control (eliminates alternate hosts)Weed control (eliminates alternate hosts) Stake plantsStake plants MulchesMulches Optimum plant spacingOptimum plant spacing Remove and destroy infected fruitRemove and destroy infected fruit Fungicide spraysFungicide sprays

Tomato Diseases - Fruit AnthracnoseTomato Diseases - Fruit AnthracnoseControl StrategiesControl Strategies

Fungicide spraysFungicide sprays Several effective fungicides availableSeveral effective fungicides available Start when first fruit reaches size of a quarterStart when first fruit reaches size of a quarter Continue weekly until harvestContinue weekly until harvest Read labels carefullyRead labels carefully

Examples of label requirements:Examples of label requirements:rate of applicationrate of applicationseasonal use limitations - amount / acre / seasonseasonal use limitations - amount / acre / seasonpre-harvest intervals pre-harvest intervals crops that can be grown in treated area next yearcrops that can be grown in treated area next year

Bacterial SpotBacterial Spot

Bacterial SpotBacterial Spot

Bacterial SpeckBacterial Speck

Bacterial SpeckBacterial Speck

Tomato Diseases - Bacterial Spot and SpeckTomato Diseases - Bacterial Spot and SpeckKey PointsKey Points

Pathogens:Pathogens:

Bacterial speck: Bacterial speck: Pseudomonas syringae Pseudomonas syringae pv.pv. tomato tomato

Bacterial spot: Bacterial spot: Xanthomonas campestris Xanthomonas campestris pv.pv. vesicatoriavesicatoria

Favored by high humidity, rainfall/irrigationFavored by high humidity, rainfall/irrigation Pathogens seed bornePathogens seed borne Dispersal - wind driven rain, clipping plants, equipment Dispersal - wind driven rain, clipping plants, equipment

moving between wet plantsmoving between wet plants Optimum temperature:Optimum temperature:

Bacterial speck: 65-75° FBacterial speck: 65-75° F Bacterial Spot: 75-85° Bacterial Spot: 75-85° FF

Tomato Diseases - Bacterial Spot and SpeckTomato Diseases - Bacterial Spot and SpeckControl StrategiesControl Strategies

Clean transplants, pathogen-free seedClean transplants, pathogen-free seed Plant rotation - at least 1-2 years between solanaceous cropsPlant rotation - at least 1-2 years between solanaceous crops Thoroughly incorporate plant debris after harvestThoroughly incorporate plant debris after harvest Application of bactericidesApplication of bactericides

Fixed coppers - alone or in combination with fungicidesFixed coppers - alone or in combination with fungicides Heavy rain, wind-driven rain, hail decrease efficacyHeavy rain, wind-driven rain, hail decrease efficacy

Buckeye RotBuckeye Rot

Soil RotSoil Rot

Tomato Diseases - Soil Rot of FruitTomato Diseases - Soil Rot of FruitKey PointsKey Points

Pathogen:Pathogen: Rhizoctonia solaniRhizoctonia solani Symptoms:Symptoms:

Rotted tissue showing concentric bands of alternating dark Rotted tissue showing concentric bands of alternating dark and light brown and light brown

Initially, rotted area is firm but becomes mushy with invasion Initially, rotted area is firm but becomes mushy with invasion of soft rotting organismsof soft rotting organisms

Affected areas eventually turn blackAffected areas eventually turn black Overwinters in soilOverwinters in soil Fungus enters tomato where fruit contacts soilFungus enters tomato where fruit contacts soil Symptoms may not be evident at harvest but can develop in storage or Symptoms may not be evident at harvest but can develop in storage or

shipmentshipment

Tomato Diseases - Soil Rot of FruitTomato Diseases - Soil Rot of FruitControl StrategiesControl Strategies

mulching around base of plants to avoid fruit contact mulching around base of plants to avoid fruit contact with soil helps prevent infectionwith soil helps prevent infection

mulches include straw, grass clippings, paper, mulches include straw, grass clippings, paper, plasticplastic

staking or caging of plants helps to avoid fruit contact staking or caging of plants helps to avoid fruit contact with soilwith soil

Tobacco Mosaic VirusTobacco Mosaic Virus

Tomato Diseases – Tobacco Mosaic Tomato Diseases – Tobacco Mosaic Virus (TMV) - Virus (TMV) - Key Points:Key Points:

Pathogen: Tobacco Mosaic VirusPathogen: Tobacco Mosaic Virus Symptoms: Symptoms:

Light and dark green mottled areas on leavesLight and dark green mottled areas on leaves Necrosis of fruit with some strainsNecrosis of fruit with some strains Stunting of plants depending on growth stage at infectionStunting of plants depending on growth stage at infection

Virus easily transmitted by workers, machineryVirus easily transmitted by workers, machinery TMV may be present in tobacco productsTMV may be present in tobacco products Virus survives on equipment, in plant debrisVirus survives on equipment, in plant debris

Tomato Diseases – Tobacco Mosaic Tomato Diseases – Tobacco Mosaic Virus (TMV) - Virus (TMV) - Control Strategies:Control Strategies:

Crop rotation – minimum of 3 yearsCrop rotation – minimum of 3 years Workers should wash hands in detergent before handling Workers should wash hands in detergent before handling

plantsplants Sanitize pruning equipment periodically Sanitize pruning equipment periodically Use cultivars with TMV resistanceUse cultivars with TMV resistance

Cucumber Mosaic VirusCucumber Mosaic Virus

Tomato Diseases – Cucumber Mosaic Tomato Diseases – Cucumber Mosaic Virus (CMV) - Virus (CMV) - Key Points:Key Points:

Pathogen: Cucumber Mosaic VirusPathogen: Cucumber Mosaic Virus Symptoms - foliar: Symptoms - foliar:

Mosaic or mottle similar to symptoms produced by TMVMosaic or mottle similar to symptoms produced by TMV ““Shoestring” appearance of leaves (filiform or threadlike)Shoestring” appearance of leaves (filiform or threadlike) General stunting of the plantGeneral stunting of the plant

Symptoms – fruit:Symptoms – fruit: Yield reduction – amount and size of fruitYield reduction – amount and size of fruit Fruit often misshapenFruit often misshapen Delay in maturityDelay in maturity

Numerous strains of the virus exist – many are specific to tomatoNumerous strains of the virus exist – many are specific to tomato Over 700 plant species are host to this virusOver 700 plant species are host to this virus Usually spread by aphidsUsually spread by aphids

Tomato Diseases – Cucumber Mosaic Tomato Diseases – Cucumber Mosaic Virus (CMV) - Virus (CMV) - Control Strategies:Control Strategies:

Eliminate weed hosts – such asEliminate weed hosts – such as MilkweedMilkweed ChickweedChickweed RagweedRagweed CloverClover White cockleWhite cockle Carpet weedCarpet weed

Plant a non-host barrier (such as corn) around the tomato Plant a non-host barrier (such as corn) around the tomato cropcrop

Double Streak VirusDouble Streak Virus

Double Streak VirusDouble Streak Virus

Blossom End RotBlossom End Rot

CatfaceCatface

Growth CracksGrowth Cracks

2,4-D Injury2,4-D Injury

Juglone ToxicityJuglone Toxicity

Juglone ToxicityJuglone Toxicity