Tomato damage can occur on one or more parts of the plant. Many symptoms of the disease often appear at the same time and the correct determination and the associated control become more complex.

Table of Contents

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  1. the essentials in brief
  2. What bad images are there?
  3. The four most common tomato diseases
  4. White, yellow, brown and black spots on leaves and stem
  5. Spots and damage on fruits
  6. What diseases can young plants get?
  7. What pests and bugs attack tomatoes?
  8. Prevent tomato diseases
  9. FAQ

    10. the essentials in brief

    • The spectrum of tomato diseases is diverse, ranging from fungal and bacterial infections to pest infestations.
    • A close examination of the entire tomato plant is essential for diagnosing the disease and subsequent treatment.
    • In many cases, preventive care avoids the onset of a serious illness.
    • Species-appropriate care in terms of watering, fertilizing and cutting out is also elementary for the health of the plant.

    What bad images are there?

    Basically, the damage patterns that occur on the tomato plant can be divided into the areas of diseases, deficiency symptoms and pests.

    tomato diseases

    The vast majority of tomato diseases result from infestation with fungal spores. They prefer a warm and humid climate. In most cases, the spread takes place by means of spray water, which reaches the lower leaves.

    deficiency symptoms

    Since tomato plants are heavy consumers, they need a consistently high amount of nutrients during the growth phase. One-sided fertilization therefore causes deficiency symptoms within a very short time.

    pests

    In the event of a pest infestation, the larvae of the insects are often more dangerous than their adult counterparts. This is mainly due to their high need for food, which causes the animals to eat up entire beds.

    The four most common tomato diseases

    The tomato plant is one of the most sensitive garden plants cultivated in our latitudes. This is partly due to the high susceptibility to various diseases.

    Late blight and late blight

    damage picture. Grey-black spotting on the upper side of the leaves. Underside of leaf covered with white coating. As the disease progresses, the leaves curl up.

    Root cause. Spread of fungal spores in a moist and warm environment with little air circulation. Wet climate due to excessive watering but also dew.

    Solution. Maintain a minimum distance between the individual plants when planting. Water the root zone only and provide a canopy. Spray onion peel stock as a preventive measure.

    tolerability of the fruit. Not edible because of the toxins it contains. Fruits that have already been harvested can also contain them.

    blossom end rot

    damage picture. Diluted patches at the base of the flowers that progressively enlarge and then sink. Rather inconspicuous spots on the leaves, but often lagging growth.

    Root cause. Calcium deficiency, which leads to the collapse of the cell structure.

    Solution. Pay attention to calcium-containing fertilization and plan care in a balanced way. In case of acute infestation, add a mixture of lime and water.

    tolerability of the fruit. Basically edible, but affected areas should be cut out.

    early blight

    damage picture. Grey-brown spots on the upper side of the leaf. spread from bottom to top. Later, spots on the shoots and rotten spots on the fruits can also be found.

    Root cause. Transmission of fungal spores by wind. The host plant is usually a nearby potato crop.

    Solution. Grow tomatoes and potatoes separately. Use and disinfect materials of the same type. Also ensure good ventilation.

    tolerability of the fruit. Still edible in the early stages of the disease. If the infestation is severe, it is better not to consume it.

    Root collar and stem rot

    damage picture. Dark discolored spots on the shoots of the plant. Punctual sinking of the plant skin. As the season progresses, the leaves will wilt and discolor.

    Root cause. Penetration of fungal spores through wounds. Spread is favored by dense vegetation and high humidity in combination with wind.

    Solution. Dispose of the affected parts of the plant in the residual waste. Preventively keep planting distance and ensure ventilation. Clean the materials used regularly. Harvest healthy fruit promptly. Do not use seeds for propagation.

    tolerability of the fruit. Cannot be eaten when infested. Disposal in the residual waste analogous to the plant parts.

    White, yellow, brown and black spots on leaves and stem

    In most cases, disease in the tomato plant can be detected in the early stages by discoloration of the leaves and stems.

    leaves

    The leaves in particular are a preferred retreat for fungal spores and insects. The undersides of the leaves are primarily used to protect the spore stores and larvae from moisture and sun.

    powdery mildew

    damage picture. Deposit of a white and at the same time mealy coating in the form of a pustule. As the disease progresses, the leaves wither and die.

    Root cause. Spread of fungal spores in a dry and warm environment by wind.

    Solution. Use low-nitrogen fertilizers. Spray field horsetail broth over the entire plant as a preventive measure. Prevent rapid drop in humidity.

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    tolerability of the fruit. Not edible because of the toxins it contains. Dispose of fruit in the residual waste to prevent further infection.

    Wrong mildew

    damage picture. White coating mainly on the underside of the leaf. Leaf surface characterized by yellowish to brownish spots. Oily appearance.

    Root cause. Spread of fungal spores by splashing water or wind in a humid environment.

    Solution. Maintain a minimum distance of 80 centimeters between the individual plants. Avoid splashing water as much as possible during daily watering. Allow air circulation through regular thinning.

    tolerability of the fruit. Fruits are not edible because of the toxins they contain. Disposal of all plant parts in residual waste.

    magnesium deficiency

    damage picture. Extreme growth in height of the plant (vergaging). Discoloration of the leaves from green to light green to yellow and later to brown due to lack of chlorophyll. Leaf veins prominent.

    Root cause. Insufficient supply of the mineral magnesium via the soil or a separate fertilizer.

    Solution. Incorporation of a complete fertilizer before planting. Continuous administration of a fertilizer containing magnesium. Use Epsom salt (10 grams per liter of water) for acute treatment of a deficiency. Epsom salt can also be added to the planting hole when planting out in May to strengthen the plant.

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    tolerability of the fruit. Still consumable without restrictions.

    leaf spot disease

    damage picture. Greyish-black spots on upper leaf surface. Black spore bearings of fungi on the underside. As the disease progresses, spots grow together to form a single area.

    Root cause. Transmission of fungal spores from neighboring plants by the wind. Celery and parsley are particularly susceptible.

    Solution. Grow tomatoes separately from celery and parsley (minimum distance: ten metres). Spray a mixture of milk and water (ratio 1:5) on the plant as a preventive measure.

    tolerability of the fruit. Fruits are not infected by the fungi and are therefore edible. However, often smaller and poorer harvests due to the infestation.

    nitrogen deficiency

    damage picture. Initial discoloration of lower leaves to yellow/brown. Further expansion upwards as the disease progresses. Leaf veins are purple in color. Overall poor growth of the plant.

    Root cause. Lack of supply of nitrogen from the soil or an equivalent fertilizer.

    Solution. Choosing a highly concentrated nitrogenous fertilizer use due to heavy nutrient depletion. Make sure that there is sufficient supply when planting.

    tolerability of the fruit. Are usually poorly formed, but are fully edible.

    bacterial wilt

    damage picture. First curling of the upper leaves, then brown spots with a yellow edge, followed by withering.

    Root cause. Use of infested seeds or unfavorable weather conditions with rain and cold.

    Solution. Direct combat is not possible. The disease is highly contagious to other tomato plants. Destroy plant residues in the bed, use high-quality seed in the following year.

    tolerability of the fruit. Fruits are usually not affected, but no recommendation for consumption. The plant should be completely destroyed and must not be put on the compost.

    spoon leafiness

    damage picture. Longitudinal curling of the leaves along the main leaf vein. Additionally sagging and drooping of the leaves.

    Root cause. Mostly care errors such as insufficient watering or over-fertilization are the cause. Strong temperature fluctuations can also lead to sagging.

    Solution. Check the soil substrate for moisture content and water the plant if necessary. Reduce fertilizer inputs for a period of four weeks to allow excess nutrients to break down.

    tolerability of the fruit. Fruits usually show little or no visual abnormalities. If necessary, remove them with a knife. However, fruits are basically completely edible.

    phosphorus deficiency

    damage picture. Overall weak plant growth in height and width. Red discoloration of the leaves.

    Root cause. Deficiency as a result of an outside temperature that is too low or an insufficient supply of nutrients.

    Solution. Provide the tomato plant with an extensive complete fertilizer and, if necessary, a special fertilizer.

    tolerability of the fruit. Predominantly only small and meager fruit development. Still easily consumable.

    velvet spot disease

    damage picture. Discoloration of leaves from green to yellow from the inside out. Underside of leaf covered with a brownish mushroom lawn.

    Root cause. Distribution of fungal spores via splashing water in an overall humid environment.

    Solution. Keep humidity low by frequent air circulation. Avoid splashing water when watering. Remove infested parts of the plant from the residual waste as soon as possible. Only use sterile tools for the work.

    tolerability of the fruit. Do not eat affected fruit. Thoroughly clean visually inconspicuous tomatoes before eating.

    stem and roots

    While diseases on the stem of the tomato plant can also be easily identified with the eye, diseases on the root ball can only be identified by digging it up. The point at which the plant emerges from the earth is therefore particularly important in this context.

    gray mold

    damage picture. Occupied with green-gray spots that continue to expand. Formation of a gray spore lawn.

    Root cause. Spread of fungal spores via spray water or the air. Preferred environment is warm and humid.

    Solution. Maintain a planting distance of at least 60 centimeters between the individual plants. Avoid splashing water as much as possible. Ensure adequate air circulation and dry climate. Strengthening with horsetail extract.

    tolerability of the fruit. Do not eat affected fruit. Disposal in residual waste required to prevent further contamination.

    Fusarium wilt

    damage picture. At the beginning of formation of whitish mycelium on the roots. It then spreads over the stem to the individual shoots.

    Root cause. Infection via permanent spores that survive in the soil substrate. Clogging of the plant's moisture pathways leads to a gradual death of the plant.

    Solution. Affected plants must be disposed of with the residual waste to avoid infection. Do not use planting sites for growing vegetables for several years. Replace soil substrate and preventively treat with lime.

    tolerability of the fruit. Fruits can no longer be eaten due to the toxins they contain. Dispose of together with the other parts of the plant in the residual waste.

    cork root disease

    damage picture. Thickening of the root ball similar to cork with subsequent dissolution of the individual root fibers. Overall only moderate growth of the tomato plant in height.

    Root cause. Fungal spores live as a permanent culture in the soil substrate and prevent the tomato from absorbing nutrients.

    Solution. No known fungicides to control it. Dispose of infested plants and soil as soon as possible. Build up the planting bed with new substrate. Perform sterilization if necessary.

    tolerability of the fruit. Fruits are usually shed independently by the plant. Can no longer be consumed due to the toxins it contains.

    Spots and damage on fruits

    The fruits of the tomato plant are rarely attacked by pathogens. The most common causes of optical changes can be found in care that is not appropriate to the species.

    sunburn

    damage picture. Glassy to whitish spots on the fruit. Possibly also burst cracks.

    Root cause. Excessive solar radiation in connection with a low self-protective effect of the plant.

    Solution. Move potted plants to a shady location. Cover specimens transplanted in the bed with a sunscreen. In addition, water generously to normalize the liquid balance again.

    tolerability of the fruit. Fruits are basically still edible. However, any cracks should be checked for infestation.

    green collar

    damage picture. Yellow-green collar on the top of the fruit that does not ripen later. Hardened pulp.

    Root cause. Often care mistakes such as severe misery, overdosing of fertilizers or excessive watering. In addition, disproportionate exposure to the sun in connection with heat build-up.

    Solution. Apply care appropriate to the species. Site selection not facing south. Favor the cultivation of light fruit varieties.

    tolerability of the fruit. Despite the greenish color it is easy to eat. Toxic ingredients such as solanine are still completely broken down. Cut out hardened areas at the base of the stem with a knife.

    Cracked/bursting fruit

    damage picture. Variously shaped cracks, usually covering the entire fruit.

    Root cause. Mainly due to too much sun exposure. However, they are also associated with excessive fertilization and irrigation.

    Solution. Protection of the plants from extreme changes by planting in a greenhouse or some other type of cover. Ensure consistent care.

    tolerability of the fruit. Fruits are still edible. Inspect tear sites for insects or other diseases.

    nose formation

    damage picture. Nose-like outgrowths usually on the top of the fruit. In individual cases, however, also on the side or on the underside.

    Root cause. Not a result of a communicable disease. Attributed to genetically predisposed seeds.

    Solution. No treatment possible due to the genetic formation. If necessary, do not continue to use contaminated seeds.

    tolerability of the fruit. No limitations in edibility and taste. Only visual flaw.

    What diseases can young plants get?

    Despite a sheltered location indoors, the seedlings of tomato plants can be afflicted by various diseases.

    damping-off

    damage picture. The young plants fall over just above the ground. Often black colored root neck.

    Root cause. Spread of fungal spores at the exit site. Prefer moist and warm environment.

    Solution. No known effective fungicide. Dispose of affected plants immediately.Avoid overwatering other plants and keep in a sunny, well-ventilated spot.

    tolerability of the fruit. Not relevant at this stage of growth. Are not yet formed by the young plants.

    curling of the leaves

    damage picture. Elongated curled leaves in connection with a yellowish discoloration and the sagging of these.

    Root cause. The cause is often a lack of liquid, but also excessive fertilization.

    Solution. Do not fertilize young plants before setting them out. Check the moisture content of the substrate with a finger test and water if necessary.

    tolerability of the fruit. Not relevant at this stage of growth. Are not yet formed by the young plants.

    What pests and bugs attack tomatoes?

    Not only pathogens can attack tomato plants, a variety of pests and beetles also prefer the nightshade family as a host plant.

    aphids

    damage picture. Black or green beetles affecting the entire plant. Egg deposits increased on the undersides of the leaves.

    Root cause. Infestation with Aphidoidea due to improper care of already weakened plants. Insufficient air and temperature circulation.

    Solution. Generously hosing down the plant with water. Then apply a mixture of water and soap (ratio 2:1). Use of natural predators such as ladybirds and lacewings. Set defensive plant partners such as nasturtium.

    tolerability of the fruit. Fruits are usually not attacked. Before eating, clean thoroughly and also examine insects.

    white flies

    damage picture. Overall poor growth of the plant. Deformation and buckling of the leaves. The undersides of the leaves are where the flies and eggs live.

    Root cause. Fly infestations with Trialeurodes vaporariorum often result from climate conditions that are too humid and poor air circulation.

    Solution. Remove and discard infested parts of the plant. Ensure adequate ventilation and dry the plant. attach yellow boards. If necessary, also use natural predators such as parasitic wasps (€22.99).

    tolerability of the fruit. Insects mostly only attack the leaves, so the fruits are still edible. Nevertheless, clean a large area before consumption.

    spider mites

    damage picture. Fine webbing on the leaf edges and shoots. Small and bright spots on the leaves. As the disease progresses, large silvery spots and curling of the leaves.

    Root cause. Tetranychidae infestation is often based on a too dry and warm climate and no regulated air exchange.

    Solution. Ensure ventilation and humidification of the plant. Apply special fertilizer with a high proportion of potassium as a preventive measure and spray field horsetail broth.

    tolerability of the fruit. If no pesticide is used, it can still be consumed. Nevertheless, examine the fruits for possible secondary diseases.

    rust mites

    damage picture. Reddish discoloration on the leaves, stems and fruits. Partly also corking of the fruits in the later stage.

    Root cause. Spread of Aculops lycopersici by air or splashing water. Transfer from other plants also possible.

    Solution. Dispose of infested plants in the residual waste as soon as possible. Use of an insecticide usually unavoidable. Preventive use of predatory mites possible.

    tolerability of the fruit. Do not eat affected fruit. Also check visually inconspicuous fruits urgently in advance.

    thrips

    damage picture. Reduced height growth and fewer and smaller fruits. Feces and droplet residue on the leaves. Yellow larvae eggs can be found on the underside of leaves.

    Root cause. Thysanoptera prefer warm and dry climates especially in poorly ventilated greenhouses.

    Solution. Rinse the plant vigorously with warm water. Followed by regular showers with nettle or onion decoction to ward off.

    tolerability of the fruit. Due to weakened growth, ripe tomatoes often do not develop. In principle, however, consumable if there is no direct infestation.

    miner fly

    damage picture. Recognizable small veins in the leaves and shoots. Later curling and dying of the leaves

    Root cause. Agromyza infestations result from warm and humid climates and irregular air circulation.

    Solution. Use of natural predators such as parasitic wasps. Deployment of crop protection nets that prevent egg laying and laying out yellow boards near the plants. The use of stinging nettle stock is also possible as a preventive measure.

    tolerability of the fruit. Insects mostly do not infest the fruit. However, check for pests before eating.

    root knot nematodes

    damage picture. Weak growth and yellowing of the leaves. In addition, thick deformations at the roots.

    Root cause. Infection via Meloidogyne incognita surviving in the soil substrate. Clogging of the plant's moisture and nutrient pathways leads to a gradual death of the plant.

    Solution. Plant defensive neighboring plants such as asparagus and corn as a preventive measure. Promote microorganisms in the soil substrate. Dispose of infested plants in the residual waste as soon as possible. Completely replace soil substrate and disinfect plant bed.

    tolerability of the fruit. Despite reduced training and gaunt form, the fruits are edible.

    Prevent tomato diseases

    Some of the diseases mentioned above can be treated only with great difficulty or not at all in the case of an existing infestation. In this context, the preventive treatment of the tomato plant against the most common pests is particularly recommended.

    Planting distance, location and bed neighbors

    In addition to the location itself, the distance to other tomato plants, but also to alien plants, also plays a decisive role. A wrongly selected place leads to reduced growth, inhibited fruit formation and also an increased susceptibility to diseases and pests. Elementary for an ideal location are therefore:

    • even exposure
    • at least seven hours of sunshine per day
    • Protection from rain and wind
    • Planting distance depends on the cultivation method (outdoor planting: 70 to 80 centimetres, greenhouse planting: 50 to 60 centimetres)
    • Prefer weak consumers such as basil, strawberries and garlic as neighbors in the bed

    defoliating and pinching

    The defoliation or the pinching of the tomato is important for the development of many flowers and fruits. In particular, the stinging shoots, which grow out of the leaf axils and only form leaves, deprive the plant of valuable nutrients.

    The tomatoes are cut at the points marked in red. Capping, defoliating and pinching are part of the weekly tomato care tasks.

    For an optimal supply of the other shoots, the stinging shoots in particular should be removed regularly. In addition, you should free the plant from the lower leaves as the height increases. Due to their proximity to the ground, these form a preferred starting point for pathogens and pests. A shortening in the upper part of the plant should be carried out primarily in the case of extreme height growth.

    Proper casting

    The spread of bacteria and fungal spores is often due to splashing water, through which the pathogens reach the tomato plant. In the course of even watering, this should therefore be avoided as far as possible. In practice, in addition to using a clay pot near the plant, the installation of a watering ring around the plant and an underground Olla have also proven themselves.

    A clay pot, a watering ring or an olla can be used to water the tomato plant without splashing water.

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    Proper fertilization

    Fertilizing is one of the essential activities of tomato care, as is pinching and watering.

    Natural fertilizers are usually more sustainable and cheaper than conventional fertilizers because you can produce them yourself

    For a particularly natural fertilization, the use of an organic fertilizer is recommended. Even if there are small differences between the individual remedies, they still cover the basic needs of the tomato. Liquid alternatives such as:

    • liquid fertilizer
    • vinasse
    • nettle manure

    Solid fertilizers such as horn shavings, (32.93€) horse manure and lawn clippings must still be worked into the soil after application. You can find more information about the individual fertilizers here.

    Depending on the chosen form of cultivation and the nutrient density of the substrate used, the amount of fertilizer that should be supplied to the plant every two weeks varies. For the different variants this means:

    • Glasshouse: 60 grams
    • pot: 80 grams
    • outdoor: 50 grams

    FAQ

    What do diseased tomato leaves look like?

    Diseased tomato leaves can be recognized by, among other things, selective discolouration, deformation and wilting. In addition, the foliage often shows pests or spore stores in the course of an infection.

    Are tomatoes with black spots edible?

    In most cases, the tomato fruits are still edible despite the discoloration. However, the affected areas should be cut out generously before consumption.

    What pests are responsible for tomato diseases?

    In addition to aphids, whiteflies, spider mites, rust mites, thrisps and leaf miners, root-knot nematodes are among the most common pests affecting tomatoes.

    What tomato diseases are there?

    The range of tomato diseases is huge. The best known include late blight, late blight, blossom end rot, early blight and root collar and stalk rot. In addition, the following diseases can also occur in tomatoes: powdery and downy mildew, leaf spot, spoon leaf, gray mold, velvet spot, Fusarium wilt, cork root disease, damping off and nutrient deficiencies.

    What Tomato Diseases Form Spots on Leaves and Fruit?

    Symptoms of late blight, late blight, root and stem rot, early blight, powdery mildew and downy mildew, gray mould, velvet spot and Fusarium wilt appear on the leaves and fruits.

    How to fight spots on leaves and fruits?

    The symptoms that have occurred should be analyzed in detail prior to any treatment. Only then should you decide which measures are to be taken specifically for the existing disease.

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Vegetable garden