Home ​​​​>​​​​ Knowledge Center​​​​

Common Tomato Diseases in Greenhouses

Tomato growers face considerable difficulties due to greenhouse tomato diseases. They cause damage to plants and fruits, reducing their value or completely disqualifying them from sale. The most common pathogens attacking greenhouse tomato crops are fungi, but also bacterial and viral diseases threaten the profitability of greenhouse cultivation.
Common tomato diseases
Jasper Verhoeven
Specialist Hygiene & Disinfection | April 24, 2023 | 4 min. lezen

Tomato diseases in greenhouses

The specificity of tomato cultivation in greenhouses, they are susceptible to different diseases than those grown in soil. both types of crops may exhibit slightly different symptoms in greenhouse than in soil. the most common diseases of greenhouse tomatoes:
Tomato fungal diseases

White mold (Sclerotinia sclerotiorum)

Leaf mold (Cladosporium fulvum)

Gray mold (Botrytis cinerea)

Early blight (Alternaria solani)


Rhisoctonia damping-off and fruit rot (Rhizoctonia Solani)


Didymella stem rot (Didymella lycopersici)

Potato blight (Phytophthora infestans)

Pythium spp

Verticillium wilt

Fusarium wilt
Bacterial diseases of tomato

Bacterial spot

Bacterial cancer



Tomato viral diseases

Tomato mosaic virus

ToBRFV virus

Pepino mosaic virus

Tomato yellow curl virus


Symptoms of greenhouse tomato diseases

Greenhouse tomato diseases can be identified by a complex of symptoms that occur on various parts of the plant, such as leaves, petales, flowers, stems, fruit, and roots. In order to accurately recognize the disease, it is necessary to carefully examine all its parts for the characteristic symptoms.
Tomato diseases

Symptoms of tomato diseases on the roots

Tomato root rot

  • Potato blight - the disease is caused by the fungus organism Phytophthora infestans, which hibernates in tomato roots and is manifested by root rot. This disease is also known as late blight. The lesions gradually develop towards the base of the stem, causing extensive brown or black spots surrounding the stem, sharply delimited.

Tomato root dieback

  • Fusarium wilt - root dieback may be a symptom of tomato gangrenous fusariosis caused by fungi of the genus Fusarium oxysporum f.sp. radicis-lycopersici. Roots affected by this disease gradually turn brown and die, and small dark spots appear on their surface. As the disease progresses, the plant's growth is inhibited, the leaves turn yellow, the stem turns brown, and gray-green or brownish streaks and kidney spots appear on its surface.

Excessive root growth

  • Crazy roots - intensive root hair growth may indicate mad root disease caused by Rhizobium rhizogenes / radiobacter. It causes the formation of white nodules and galls on the stems which turn brownish over time. The disease causes excessive vegetative growth of plants and inhibition of fruit development.

Symptoms of tomato diseases on fruits

Diseases affecting tomato fruits are particularly dangerous for greenhouse tomato crops, as it is the fruit that is the commercial material. In many cases, tomatoes become unsaleable due to stains, discolorations, and deformations, which reduces their value and leads to less sales and yield.

Tomato root rot

  • White mold - stem rot of tomatoes with an accompanying whitish, abundant mycelium coating may indicate sclerotinia sclerotiorum fungus, white mold. In addition to fruit symptoms, the disease manifests itself as whitish, dry-surfaced spots on the stem. A wadded mycelium forms inside the stem, with visible black spots - sclerotia of the fungus.
  • Gray mold – gray mold, caused by the fungus Botrytis cinerea, can also lead to tomato fruit rot. Infection of the plant can also be identified by gray-green or yellowish, concentric spots on the leaves and stems, which are covered with a fluffy, gray coating of the fungus at higher air humidity.
Potato blight
Potato blight on tomatoes
Potato blight (Phytophtora infestans) shows symptoms on fruit as green or brown, irregular, hard-surfaced spots. Similar stains appear on leaves and stems. The disease can also be identified by root rot.

ToBRFV
Tomato brown rugose fruit virus
Tomato brown rugose fruit virus (ToBRFV) causes black spots and spots on tomato fruits, which are also accompanied by changes on leaves: mosaic discoloration on their surface and fernness. Oblong nephrosis appear on the stems, leading to the withering of the shoots.

Gray mold
Gray mold
Wet rot spots appearing on the tomato surface may indicate that the plant has been infected with Botrytis cinerea. As the disease progresses, the spots become covered with a white coating of mycelium, and then - with gray dust of conidia spores.

  • Tomato mottle virus (TMoV) - The spots caused by this disease are mottled in shape, small and brown in color. In addition to the characteristic spots, the disease is manifested by limited fruit setting, as well as the appearance of watery, dark green, irregular spots on the leaves surrounded by a yellow halo. Infected leaves gradually die, flower buds become covered with very small, black spots, and stems - dark brown, extensive, elongated nephrosis.
  • Early blight - black spots on a tomato, with a leathery structure and concentric spheres, may indicate that the plant is infected with a fungus of the genus Alternaria solani, causing Alternaria or early blight in tomato. In addition to the symptoms on the fruit, the disease also manifests itself on the stems, on which elongated, slightly concave spots appear, slightly lighter in the center than at the edges. Leaves turn yellow and curl, with dark brown, round or slightly angular spots delimited by veins appear on their surface.
  • Bacterial cancer - raised spots on tomato fruit surrounded by a white border may indicate infection by the bacterium Clavibacter michiganensis . Along with the spots, a whitish reticulation is visible through the peel, as well as yellowish colored conductive bundles. The leaves curl and dry, and whitish kidney spots appear on their surface. The stem is covered with brown-black streaks and deep, longitudinal cracks, from which bacterial mucus comes out at high humidity.
  • Pepino mosaic virus (PepMV) - gives symptoms in the form of marbled, red-orange spots on the surface of the fruit, accompanied by a mosaic of leaves and chlorotic spots on their surface. Stems become covered with kidneys and gradually die.

Symptoms of tomato diseases on leaves

There are many diseases that attack tomato cultivation crop that can be identified by blotches and deformation of the leaves. The symptoms seen on leaves are usually the first to appear in a crop, but to determine which pathogen is attacking the plants, they should be compared to those seen on other parts of the plant: fruits, shoots, and roots.

Spots on tomato leaves

The size, color and structure of the lesions on the leaves provide a valuable clue about a pathogen that may attack the crop. However, it is worth remembering that the final diagnosis should be made only on the basis of a number of symptoms - this will allow for the accurate identification of the disease and quick action to combat it. 

  • Tomato Bacterial speck - the appearance of dark green, watery, irregularly-shaped spots surrounded by a yellowish border on the leaves may indicate that the crop is infected with the bacterium Pseudomonas syringae. As the disease develops, the leaves dry out and the flower buds become covered with very fine black spots. Elongated, dark brown spots appear on the stems, and small brown spots appear on the fruit.
  • Gray mold (Botrytis cinerea) - the disease manifests itself as gray-green or yellowish spots with concentric zoning. In conditions of higher humidity, a fluffy, gray coating of the fungus appears on the leaves, which also covers the shoots and fruits. The fruits are additionally covered with watery gray or yellow-green spots and rot. In an advanced stage, the rot may even affect the whole fruit.
  • Early blight (Alternaria solani) - the spots on the leaves accompanying this disease take a round or slightly angular shape, limited by nerves, and a dark brown color. This is accompanied by curling and yellowing of the leaves. Symptoms also appear on the stem in the form of elongated, slightly concave spots, slightly lighter in the center than at the edges, and on the fruit - in the form of dark brown or black, leathery, slightly recessed spots with concentric zoning.
  • Tomato Mosaic virus (ToMV) - a green or yellow mosaic on the leaves with the accompanying threadlike, fern-like leaves and streakiness of the stem may indicate that the plant is infected with the tomato mosaic virus. With the development of the disease, weaker fruit set can be observed, and those that develop are small, distorted and unevenly colored.
  • Potato blight (Phytophtora infestans) - grayish or green-brown, kidney spots on tomato leaves with accompanying extensive, brown-black spots, sharply demarcated from healthy tissue, may indicate that the plant is infected with the pathogen ver . In addition to the symptoms on the leaves and stems, the symptoms of the disease can be observed on the fruit as irregular, bulging spots with a hard surface, and on the roots - in the form of rot.
  • Verticillium wilt - brownish or grayish V-shaped spots may indicate an attack of the plant by fungi of the Verticillium dahliae group . As the disease progresses, apart from leaf spots, a gradual wilting of the apical leaves can be observed.
  • Tomato brown rugose fruit virus - spots on tomato leaves, indicating that the plant is infected with ToBRFV, have the character of mosaic discoloration. They are accompanied by fern leaves, oblong nephrosis on the stem and the appearance of black spots and points on the fruit.
  • Pepino mosaic virus (PepMV) - the appearance of chlorotic spots on the leaves and covering their surface with a characteristic mosaic may indicate that the plant has been infected by the Pepino mosaic virus. Additional symptoms of the disease are visible on the fruit as marbled orange-red spots.
Tomato bacterial cancer
Tomato Bacterial cancer
The appearance of whitish, kidney-shaped spots on the leaves as well as brown-black streaks and deep, longitudinal cracks, covered with bacterial slime, may indicate Bacterial Cancer (Clavibacter michiganensis) of the tomato. The leaves curl and die, and the fruit shows a whitish mesh, showing through the skin. The conductive bundles turn yellow, and bulging spots appear on the surface of the fruit, surrounded by a white border.
Powdery mildew
Powdery mildew
Small, round, white spots appearing on tomato leaves, accompanied by a white, powdery coating may indicate infection of the plant by Oidium lycopersicum fungi, causing tomato powdery mildew. As the disease progresses, the raid covers the upper parts of the plant, leading to the death of leaves and shoots.

Leaf mold
Leaf mold (Cladosporium fulvum)
Small, yellow-brown spots, gently demarcated from healthy tissue, may be a sign of a brown spot on tomato leaves. A gray, brown or purple coating of the fungus appears on the underside of the leaf.

Tomato leaves curling

  • Early blight (Alternaria solani) - in the course of this disease, leaf curl is accompanied by the appearance of dark brown, round or slightly angular spots, delimited by veins. The fruit is also damaged and covered with dark brown or black, slightly recessed spots with a leathery surface and concentric spheres.
  • Bacterial cancer (Clavibacter michiganensis) - leaves of a plant infected with this disease dry and curl, and whitish, renal patches appear on their surface. Dark brown streaks and deep longitudinal cracks appear on the stem, which become covered with bacterial mucus at high air humidity. The disease is also visible on fruits with whitish reticulation translucent through the skin. Conductive bundles change color to yellow and on the surface of the fruit.
  • Tomato yellow leaf curl virus (TYLCV) - leaf edge curl in the development of this disease is accompanied by twisting of the growth cones, which is a characteristic symptom of the disease. In addition, the leaves are smaller and discolored yellow, especially between the veins and at the edges. The virus severely reduces fruit setting, causing large losses in the crop.

Tomato crop control

There are a number of fungicides designed to fight specific pathogens to combat treat tomato fungal diseases. Rapid detection of the pathogen and taking immediate action allows you to combat control the disease and minimize crop losses. This is not the case with most bacterial and viral diseases. In that case, fighting treating disease with chemical or biological agents is ineffective. It is therefore of key importance to prevent the appearance of the pathogen in the crop by maintaining high standards of hygiene and disinfection. After detecting a viral disease in the crop, immediately remove the infected plant parts or whole plants and dispose of them. To prevent the disease from spreading between successive rows of plants, disinfect all tools and items used in the greenhouse.
Contact form
Can’t find your answer? Fill out the contact form and Jasper Verhoeven will reach out to you. On week days, you will receive a response within 24 hours. 

Common Tomato Diseases in Greenhouses

Tomato growers face considerable difficulties due to greenhouse tomato diseases. They cause damage to plants and fruits, reducing their value or completely disqualifying them from sale. The most common pathogens attacking greenhouse tomato crops are fungi, but also bacterial and viral diseases threaten the profitability of greenhouse cultivation.
Search in the Knowledge Center
Find answers to your question in our Knowledge Center. 600+ articles, written by our specialists.
Jasper Verhoeven
Jasper Verhoeven
Specialist Hygiene & Disinfection | April 24, 2023 | 4 min. lezen
Deel dit artikel
Common tomato diseases

Tomato diseases in greenhouses

The specificity of tomato cultivation in greenhouses, they are susceptible to different diseases than those grown in soil. both types of crops may exhibit slightly different symptoms in greenhouse than in soil. the most common diseases of greenhouse tomatoes:
Tomato fungal diseases

White mold (Sclerotinia sclerotiorum)

Leaf mold (Cladosporium fulvum)

Gray mold (Botrytis cinerea)

Early blight (Alternaria solani)


Rhisoctonia damping-off and fruit rot (Rhizoctonia Solani)


Didymella stem rot (Didymella lycopersici)

Potato blight (Phytophthora infestans)

Pythium spp

Verticillium wilt

Fusarium wilt
Bacterial diseases of tomato

Bacterial spot

Bacterial cancer



Tomato viral diseases

Tomato mosaic virus

ToBRFV virus

Pepino mosaic virus

Tomato yellow curl virus




Symptoms of greenhouse tomato diseases

Greenhouse tomato diseases can be identified by a complex of symptoms that occur on various parts of the plant, such as leaves, petales, flowers, stems, fruit, and roots. In order to accurately recognize the disease, it is necessary to carefully examine all its parts for the characteristic symptoms.
Tomato diseases

Symptoms of tomato diseases on the roots

Tomato root rot

  • Potato blight - the disease is caused by the fungus organism Phytophthora infestans, which hibernates in tomato roots and is manifested by root rot. This disease is also known as late blight. The lesions gradually develop towards the base of the stem, causing extensive brown or black spots surrounding the stem, sharply delimited.

Tomato root dieback

  • Fusarium wilt - root dieback may be a symptom of tomato gangrenous fusariosis caused by fungi of the genus Fusarium oxysporum f.sp. radicis-lycopersici. Roots affected by this disease gradually turn brown and die, and small dark spots appear on their surface. As the disease progresses, the plant's growth is inhibited, the leaves turn yellow, the stem turns brown, and gray-green or brownish streaks and kidney spots appear on its surface.

Excessive root growth

  • Crazy roots - intensive root hair growth may indicate mad root disease caused by Rhizobium rhizogenes / radiobacter. It causes the formation of white nodules and galls on the stems which turn brownish over time. The disease causes excessive vegetative growth of plants and inhibition of fruit development.

Symptoms of tomato diseases on fruits

Diseases affecting tomato fruits are particularly dangerous for greenhouse tomato crops, as it is the fruit that is the commercial material. In many cases, tomatoes become unsaleable due to stains, discolorations, and deformations, which reduces their value and leads to less sales and yield.

Tomato root rot

  • White mold - stem rot of tomatoes with an accompanying whitish, abundant mycelium coating may indicate sclerotinia sclerotiorum fungus, white mold. In addition to fruit symptoms, the disease manifests itself as whitish, dry-surfaced spots on the stem. A wadded mycelium forms inside the stem, with visible black spots - sclerotia of the fungus.
  • Gray mold – gray mold, caused by the fungus Botrytis cinerea, can also lead to tomato fruit rot. Infection of the plant can also be identified by gray-green or yellowish, concentric spots on the leaves and stems, which are covered with a fluffy, gray coating of the fungus at higher air humidity.
Potato blight
Potato blight on tomatoes
Potato blight (Phytophtora infestans) shows symptoms on fruit as green or brown, irregular, hard-surfaced spots. Similar stains appear on leaves and stems. The disease can also be identified by root rot.

ToBRFV
Tomato brown rugose fruit virus
Tomato brown rugose fruit virus (ToBRFV) causes black spots and spots on tomato fruits, which are also accompanied by changes on leaves: mosaic discoloration on their surface and fernness.

Gray mold
Gray mold
Wet rot spots appearing on the tomato surface may indicate that the plant has been infected with Botrytis cinerea. As the disease progresses, the spots become covered with a white coating of mycelium, and then - with gray dust of conidia spores.

  • Tomato mottle virus (TMoV) - The spots caused by this disease are mottled in shape, small and brown in color. In addition to the characteristic spots, the disease is manifested by limited fruit setting, as well as the appearance of watery, dark green, irregular spots on the leaves surrounded by a yellow halo. Infected leaves gradually die, flower buds become covered with very small, black spots, and stems - dark brown, extensive, elongated nephrosis.
  • Early blight - black spots on a tomato, with a leathery structure and concentric spheres, may indicate that the plant is infected with a fungus of the genus Alternaria solani, causing Alternaria or early blight in tomato. In addition to the symptoms on the fruit, the disease also manifests itself on the stems, on which elongated, slightly concave spots appear, slightly lighter in the center than at the edges. Leaves turn yellow and curl, with dark brown, round or slightly angular spots delimited by veins appear on their surface.
  • Bacterial cancer - raised spots on tomato fruit surrounded by a white border may indicate infection by the bacterium Clavibacter michiganensis . Along with the spots, a whitish reticulation is visible through the peel, as well as yellowish colored conductive bundles. The leaves curl and dry, and whitish kidney spots appear on their surface. The stem is covered with brown-black streaks and deep, longitudinal cracks, from which bacterial mucus comes out at high humidity.
  • Pepino mosaic virus (PepMV) - gives symptoms in the form of marbled, red-orange spots on the surface of the fruit, accompanied by a mosaic of leaves and chlorotic spots on their surface. Stems become covered with kidneys and gradually die.

Symptoms of tomato diseases on leaves

There are many diseases that attack tomato cultivation crop that can be identified by blotches and deformation of the leaves. The symptoms seen on leaves are usually the first to appear in a crop, but to determine which pathogen is attacking the plants, they should be compared to those seen on other parts of the plant: fruits, shoots, and roots.

Spots on tomato leaves

The size, color and structure of the lesions on the leaves provide a valuable clue about a pathogen that may attack the crop. However, it is worth remembering that the final diagnosis should be made only on the basis of a number of symptoms - this will allow for the accurate identification of the disease and quick action to combat it. 

  • Tomato Bacterial speck - the appearance of dark green, watery, irregularly-shaped spots surrounded by a yellowish border on the leaves may indicate that the crop is infected with the bacterium Pseudomonas syringae. As the disease develops, the leaves dry out and the flower buds become covered with very fine black spots. Elongated, dark brown spots appear on the stems, and small brown spots appear on the fruit.
  • Gray mold (Botrytis cinerea) - the disease manifests itself as gray-green or yellowish spots with concentric zoning. In conditions of higher humidity, a fluffy, gray coating of the fungus appears on the leaves, which also covers the shoots and fruits. The fruits are additionally covered with watery gray or yellow-green spots and rot. In an advanced stage, the rot may even affect the whole fruit.
  • Early blight (Alternaria solani) - the spots on the leaves accompanying this disease take a round or slightly angular shape, limited by nerves, and a dark brown color. This is accompanied by curling and yellowing of the leaves. Symptoms also appear on the stem in the form of elongated, slightly concave spots, slightly lighter in the center than at the edges, and on the fruit - in the form of dark brown or black, leathery, slightly recessed spots with concentric zoning.
  • Tomato Mosaic virus (ToMV) - a green or yellow mosaic on the leaves with the accompanying threadlike, fern-like leaves and streakiness of the stem may indicate that the plant is infected with the tomato mosaic virus. With the development of the disease, weaker fruit set can be observed, and those that develop are small, distorted and unevenly colored.
  • Potato blight (Phytophtora infestans) - grayish or green-brown, kidney spots on tomato leaves with accompanying extensive, brown-black spots, sharply demarcated from healthy tissue, may indicate that the plant is infected with the pathogen ver . In addition to the symptoms on the leaves and stems, the symptoms of the disease can be observed on the fruit as irregular, bulging spots with a hard surface, and on the roots - in the form of rot.
  • Verticillium wilt - brownish or grayish V-shaped spots may indicate an attack of the plant by fungi of the Verticillium dahliae group . As the disease progresses, apart from leaf spots, a gradual wilting of the apical leaves can be observed.
  • Tomato brown rugose fruit virus - spots on tomato leaves, indicating that the plant is infected with ToBRFV, have the character of mosaic discoloration. They are accompanied by fern leaves, oblong nephrosis on the stem and the appearance of black spots and points on the fruit.
  • Pepino mosaic virus (PepMV) - the appearance of chlorotic spots on the leaves and covering their surface with a characteristic mosaic may indicate that the plant has been infected by the Pepino mosaic virus. Additional symptoms of the disease are visible on the fruit as marbled orange-red spots.
Tomato bacterial cancer
Tomato Bacterial cancer
The appearance of whitish, kidney-shaped spots on the leaves as well as brown-black streaks and deep, longitudinal cracks, covered with bacterial slime, may indicate Bacterial Cancer (Clavibacter michiganensis) of the tomato. The leaves curl and die, and the fruit shows a whitish mesh, showing through the skin. The conductive bundles turn yellow, and bulging spots appear on the surface of the fruit, surrounded by a white border.
Powdery mildew
Powdery mildew
Small, round, white spots appearing on tomato leaves, accompanied by a white, powdery coating may indicate infection of the plant by Oidium lycopersicum fungi, causing tomato powdery mildew. As the disease progresses, the raid covers the upper parts of the plant, leading to the death of leaves and shoots.

Leaf mold
Leaf mold (Cladosporium fulvum)
Small, yellow-brown spots, gently demarcated from healthy tissue, may be a sign of a brown spot on tomato leaves. A gray, brown or purple coating of the fungus appears on the underside of the leaf.

Tomato leaves curling

  • Early blight (Alternaria solani) - in the course of this disease, leaf curl is accompanied by the appearance of dark brown, round or slightly angular spots, delimited by veins. The fruit is also damaged and covered with dark brown or black, slightly recessed spots with a leathery surface and concentric spheres.
  • Bacterial cancer (Clavibacter michiganensis) - leaves of a plant infected with this disease dry and curl, and whitish, renal patches appear on their surface. Dark brown streaks and deep longitudinal cracks appear on the stem, which become covered with bacterial mucus at high air humidity. The disease is also visible on fruits with whitish reticulation translucent through the skin. Conductive bundles change color to yellow and on the surface of the fruit.
  • Tomato yellow leaf curl virus (TYLCV) - leaf edge curl in the development of this disease is accompanied by twisting of the growth cones, which is a characteristic symptom of the disease. In addition, the leaves are smaller and discolored yellow, especially between the veins and at the edges. The virus severely reduces fruit setting, causing large losses in the crop.

Tomato crop control

There are a number of fungicides designed to fight specific pathogens to combat treat tomato fungal diseases. Rapid detection of the pathogen and taking immediate action allows you to combat control the disease and minimize crop losses. This is not the case with most bacterial and viral diseases. In that case, fighting treating disease with chemical or biological agents is ineffective. It is therefore of key importance to prevent the appearance of the pathogen in the crop by maintaining high standards of hygiene and disinfection. After detecting a viral disease in the crop, immediately remove the infected plant parts or whole plants and dispose of them. To prevent the disease from spreading between successive rows of plants, disinfect all tools and items used in the greenhouse.
Contact form
Can’t find your answer? Fill out the contact form and Jasper Verhoeven will reach out to you. On week days, you will receive a response within 24 hours. 
Jasper Verhoeven
Also interesting for you
Botrytis Cinera - Grey Mold
Botrytis is a fungus and is the largest cause of damage in horticulture. This fungus is also known as Botrytis cinerea, grey rot, grey mould, mould fungus or tomato plant disease. The fungus is mainly found in crops with a high humidity.
Fusarium
Fusarium oxysporum, also known as tomato wilt or Fusarium wilt, is soil fungus which is common in greenhouse crops. Almost every crop has specific type Fusarium, but this fungus is mainly a problem in cucumber, pepper, tomato, pot plants and cut flowers.
How do you control crazy roots?
Crazy roots, or excessive root growth, is caused by the Agrobacterium rhizogenes bacterium and is found in tomato, cucumber, eggplant and zucchini crops.