Gardening Growing Tomatoes

10 Common Tomato Leaf Problems and Solutions

Tomato leaf problems appear in different stages of plant growth. It may happen for various reasons like environmental effects, lack of tomato care and pathogenic attack.

The leaf problems are also a symptom or side effects of some diseases. So, continue reading to know the most common leaf problems of tomatoes and the possible solutions.

01: Gray Leaf Spot

Gray leaf spot of tomato is a fungal disease mostly affected the southern states of the United States. It affects the leaves primarily.  Stemphylium Solani, Stemphylium Floridanum, and Stemphylium Botryosum fungus are the main reason to outbreak this disease.

Causes and Symptoms:

They can attack tomato leaves at any stage of their life and leaves die and fall consistently. As a result, sunscald appeared on fruits, affect the plants health and reduce production. 

You can find yellow halo on leaves which contain black specks circling brownspots.They create holes and ultimately the leaves drop.  

The fungus can survive easily on garden plant debris including tomatoes and other species of nightshade plants like peppers, eggplants, and potatoes. They spread out through rain and wind as well as when finding warm or wet weather and due to overhead watering.

Treatments and controls:

Disease-resistant code: “St”

  • Prevention is the easiest way to protect gray leaf spot. So always keep on checking your tomato plants.
  • You can use early season fungicides for treating gray leaf spot and other fungal diseases.
  • Keep your garden weed free and clear the plant debris.
  • Sanitize your garden tools regularly and wash your hands properly.
  • Crop rotation can reduce the chance to spread out this disease but remember don’t pick the similar species of plants as an alternate crop like peppers, eggplants or potatoes.
  • Find some diseases resistant tomato varieties in your respective planting zone.
  • Confirm enough sunlight for the tomato plants and extra space in between two plants for aeration.
  • Ensure proper drainage system and keep the plant leaves dry.
  • Immediately destroy the affected tomato plants and dig a deep hole to dump and cover the plant debris at the end of the season.
Gray Leaf Spot Resistant Tomato Varieties

02: Septoria Leaf Spot

Septoria leaf spot of tomato is a devastating fungal disease mainly attack the plant leaves due to a fungus called Septoria Lycopersici. It attacks the older leaves at firstfrom the bottom of plants, then gradually jump to newer leaves upwards butrarely harm the fruits.

Tomato Septoria leaf spot
Image source: Scot Nelson

Causes and symptoms:

Septoria leaf spots scattered when getting wet and humid weather for a longer period. They can travel by wind and rain and outbreak in temperatures of 60°-80° Fahrenheit. 

At the first stage, some water-soaked small spots appear on the undersides of leaves.

The second stage, spots growing matures, bigger and coalesce.

The final stage, the spots turned into a dark brown pimple-like structure in the center.

Extremely infected leaves fall off and weakening the plants.

Treatments and controls:

Disease-resistant code: “S” or “SLS”

  • Remove the infected leaves and destruct to reduce the risk of the disease.
  • Dispose of the garden plants debris (leaves and stems of nightshade family plants) by dumping or burning.
  • Use a fungicidal sprayer to protect the disease to grow further and attack new leaves.
  • Using crop rotation is a wise way to skip this fungal problem. Keep away from tomato cultivation at least two years or change the location.
  • Hygiene gardening tools after working in the field.
  • Regular mulching and staking plants for proper air circulation to reduce the chance of flourishing the disease.
  • Find some disease-resistant tomato varieties.
  • Using a raised bed for a proper drainage system to avoid Septoria leaf spots.
Septoria Leaf Spot Resistant Tomato Varieties

03: Leaf rolling or curling

Tomato leaf curling and rolling is a common matter for tomato gardener. This may occur for physiological condition, a side effect of herbicides or viral attack. You have to take precautions after finding out the main cause of the leaves rolling.

Leaf rolling, Tomato yellow leaf curl virus, TYLCV
Image source: Scot Nelson

Causes and symptoms:

Physical causes:

Sometimes environmental effects can push to make it happen with plants. When the season jump from spring to summer it may occur for overheating or drought.

Besides, rainy weather condition including extremely cool temperature also helps to make it happen.

Transplanting of seedlings, over-pruning, lack of water supply or root damages can cause leaves rolling.

Herbicide effects:

Using herbicides or over spraying in your garden can cause leaf curling. Stems turning white and leaves turning puckered due to herbicide effects. Sometimes fruit may deform and plants can’t survive due to overexposure of herbicide.

Viral effects:

Tomato leaf rolling sometimes cause by a virus called tomato yellow leaf curl virus (TYLCV) which is transmitted through white flies. At the beginning the leaves rolling upwards, then the color of the leaves turning yellow and the leaves become crumbly. It hampers new blooming and regular plant growth, which significantly reduces fruit production.

Sometimes tomato mosaic virus causes tomato leaves rolling.

Treatments and controls:

Disease-resistant code: “TYLCV”

  • Tomato leaves rolling for physical causes doesn’t change the quantity or quality of the fruit production and you don’t have to take any step to recover the problem. Leaf curl will be recovered in a few days; you just need to supply water for the plants regularly.
  • To reduce herbicide exposure, use a separate sprayer for your tomato plants and lawn. Avoid mulching around tomato plants using grass clippings and watering your plants regularly to recover minor herbicide exposure.
  • There was no effective solution for a viral attack of leaves rolling. The best way to protect the virus transmitter (white flies) through biological control using garden-friendly bugs such as big-eyed bugs, lacewing larvae, and lady beetle larvae.
  • Transplant disease-free seedlings for tomato production. Regularly check your tomato plants and if you get any symptom of viral attack, immediately remove and destroy the infected plants.
Tomato Yellow Leaf Curl Virus (TYLCV) Resistant Varieties

04: Tomato spotted wilt virus

Tomato spotted wilt disease is a virus transmitted disease caused by TSWV virus and spread out through insects named Thrips. This is a devastating disease that economically affects around 35 plant families and a major threat for tomato growers.

This virus better performs in warm condition,temperate zones, subtropical, and tropical regions around the world. Besides, this can also attack in greenhouse condition.

There has no remedy for this virus but you can take some precautions as preventative to reduce the risk.

Causes and symptoms:

Spotted wilt spread out by small insect Thrips which survive by sucking tomato or other plants content. At the larval stage, it contains the TSWV virus then growing to be adult to transmit the disease from infected plants to healthy plants.

Symptoms included bronze, purplish or dark-spotted leaves and brownish or yellow color ring spot on fruits are very common to recognize the virus.

Treatments and controls:

Disease-resistant code: “TSWV”

  • Disease resistant tomato varieties are recommended to avoid this problem if your planting zone is infested by this virus.
  • Immediately remove and destroy the infected plants if you recognize earlier the symptoms. It will help you to prevent spreading out the disease.
  • Weed control is another way to control tomato spotted wilt virus. Always keep your garden free from weeds and other garden debris.
  • Some beneficial garden insects such as Minute pirate bugs and Big-eyed bugs can be used as predators to control Thrips.
  • Virus transmitted diseases have no effective treatment so prevention is the best way to protect the threat.
Tomato Spotted Wilt Virus Resistant Varieties,  TSWV

05: Fusarium wilt

Fusarium wilt of tomato is a fungal disease caused by Fusarium Oxysporum. This is a soil-borne disease which develops in warm condition and sandy or acidic soil throughout the United States.  They enter the plants using roots and restrict water circulation in plants and the leaves become wilt and turn yellow.

Besides tomato, they can also attack potato, eggplant and pepper plants.

Fusarium wilt of tomatoes
Image Source: F. D. Richards

Causes and symptoms:

Fusariumwilt often attacks when the fruits begin mature and you can see leaves turn yellow from the bottom of the plant. Most of the time they affect from one side of the plant or leaves or branches.

This fungal disease hampers the plants’ growth and stop producinng new fruit.

The disease spread out easily when the temperature reaches 80°-90° Fahrenheit. Besides imbalanced soil nutrients such as high nitrogen and low potassium also responsible for outbreak Fusarium wilt disease. 

Treatments and controls:

Disease-resistant code: “F” or “FF” or “FFF”

  • This fungus can survive in the soil or plants debris up to 10 years, so find some disease-resistant tomato varieties in your area. Crop rotation is another way to prevent the disease.
  • Avoid planting Solanaceous plants (such as tomato, potato, pepper or eggplant) at least five years in your garden if you garden infected by the disease.
  • Remove and destroy affected tomato plants of your garden.
  • Weed control is another way to prevent the disease.
  • Create a proper drainage system and avoid working in wet soil. The disease can transfer by your shoes. You can also use a container using new soil to protect the disease.
  • Test your garden soil to measure the soil nutrient and proper distribution of fertilizer. Use well balanced or organic fertilizer to reduce the risk of the disease.
  • Sanitize your garden tools regularly to prevent the disease.
  • There has no treatment for the disease. So, the above precaution is essential to protect Fusarium wilt.
Fusarium Wilt Resistant Tomato Varieties (All 3 Races)

06: Verticillium Wilt

Verticillium Wilt of tomato is a soil-borne fungus caused by the pathogen Verticilliurn Albo-atrium. It is commonly found in cooler soil of the northern region of the United States.

It can affect more than 200 plant species, especially nightshade family plants including tomatoes, eggplants, peppers, potatoes, and other host plants. 

Causes and symptoms:

Older leaves near soil turn yellow and curl upwards during daytime and reopen at night. Slowly the leaves turn brown from yellow and finally drop off.

The pathogen mostly attacks the older and lower level leaves and only the upper leaves remain green. Sunscald appears on tomato fruits due to drop off as well as the removal of infected foliage.

Fruit size becomes smaller due to the attack of the disease and the symptom mostly noticeable when the plants start producing fruits. Fruits start dropping off from the infected stems before they are ripe.

The fungus spread out when soil temperature remains between 60°-75° Fahrenheit with the presence of high moisture. Poorly drainage system helps to flourish the fungus more quickly.

Treatments and controls:

Disease-resistant code: “V”

  • There is no chemical treatment, so choose verticillium fungus resistant tomato varieties.
  • Well-drained soil keeps balance the soil moisture and reduces the risk of infection.
  • Dispose of the infected plants by burning them after the season end.
  • Avoid planting tomatoes and other Solanaceous crops in your garden area for four years to remove the fungus if exist.
  • Sanitize your garden tools after works and don’t move in the garden when the soil is wet.
Verticillium Wilt Resistant Tomato Varieties

07: Tomato Bacterial Wilt

Bacterial wilt of tomato often called southern bacterial wilt is a serious soil-borne disease caused by the pathogen bacterium Ralstonia Solanacearum. The bacterium exists in the soil and thrives in highly warm and humid weather condition. 

It attacks more than 200 plant species all over the world including susceptible host plants like tomato, eggplant, pepper, and potato.

Causes and symptoms:

Symptoms first appear on the youngest leaves during the hottest time of the day.

Plants start to be wilted in the day time and recover at night.

Acidic soil, infertile soil, and heavy clay soil encourage thriving diseases.

Wet and humid weather condition after heavy rainfall when the temperature goes above 85°F, helps to thrive the disease.

The disease can spread out through running water and infected soil mixing with uninfected soil.

Plants become wilted when the disease develops and it can attack at any stage of the growing period especially the plants set fruit.

The bacterium also hampers plant growth. 

The whole plant becomes wilted quickly when the symptom appears and finally leaves turn yellow before the death of the plants.

Pruning plant stems, insect attacks on plants or any types of injury over the tomato plants can cause bacterial wilt. High pH on soil can also invite the pathogen. 

Clearly identify the bacterial wilt attack, just cut off a finger length main stem from an infected tomato plant and sink it to a glass of water for few minutes and you can see milky white bacteria will appear on the stem.

Treatments and controls:

Disease-resistant code: “BW”

  • No chemical control available for the bacterial wilt so chooses resistant varieties.
  • If your plants once infected by the bacterial wilt, rotate your crop cycle for four years and avoid planting tomato, eggplant, pepper, potato, and other susceptible host plants.
  • Maintain proper drainage system with required soil pH around 6 to 7 in scale.
  • Pay more attention when working in the garden and try to minimize root damages and plant injuries.
  • Burn the infected plants as soon as found and remove the surrounding soil of the infected plants from your garden.
  • Use raised bed and container if your garden area infested by the disease.
  • Always wash your plants properly after working in the garden.
  • Remove and burn your garden debris after finishing each season.
Bacterial Wilt Resistant Tomato Varieties

08: Tomato Powdery Mildew

Powdery mildew of tomato is a common fungal disease caused by the pathogen Leveillula Taurica. This is mainly a warm and dry climate disease.

Powdery mildew is a foliar disease which doesn’t attack the fruits and stems of tomato plants.

It has a narrow area of host plants like nightshade family plants and mostly infects the home garden rather than a commercial garden.

Tomato Powdery Mildew
Image Source: Scot Nelson

Causes and symptoms:

Pale yellowish spots appear on foliar at the beginning stage. Soon the spots covered with flour type mildew. As the disease develops the spots turn into brown and shrivel.

It is more susceptible in late summer.

Old and stressed plants are mostly affected by the disease.

Plants become weak due to foliar damages and insufficient energy sources which resulting drop off of leaves.

Plants growth stunted and fruits from infected plants become less flavorful.

Treatments and controls:

Disease-resistant code: “PM”

  • Provide adequate soil nutrient and air circulation around the plants.
  • Pick out the infected leaves and harvest tomatoes from the infected plants as soon as you noticed.
  • Remove and buried the infected plans to prevent the disease spread out to next season.
  • Apply sulfur fungicide to protect your tomato plants before establishing powdery mildew. Or use neem oil, horticultural oil, jojoba oil, and biological fungicide to destroy the infection after appearance.
  • You can also use milk solution spray to control powdery mildew;take 1 part of milk diluted in 10 parts of waterand maintain a schedule spray every 10 days interval after the symptom appearance.
Powdery Mildew Resistant Tomato Varieties

09: Tomato Leaf Mold

Leaf mold of tomato is a fungal disease caused by the pathogen Passalora Fulva, mostly infect the tomato foliage.

The pathogen thrives in a humid weather condition especially common in greenhouses and high tunnels.

This fungus has no hosts and only infects the tomato plants.

Causes and symptoms:

Oldest leaves are primarily infected and appear pale greenish to yellow spots without definite borderline on the upper leaf surface.  The infected leaves may seem yellowing due to lack of nutrients.

On the other hand, the lower leaf surface appearsolive-green to brownish spots right below the upper yellowish spots. Shortly the spots becoming darker and develop velvety appearance.

Before long the leaf spots grow together turning brown and wither, finally die before mature and stick to the plant.

The pathogen attacks the plants when the humidity level goes above 85%.

The fungi can perform better at a temperature between 71°F to 75°F, but it can also susceptible at a temperature from 40°F to 90°F range.

Symptoms sometimes also appear on blossoms, stems, and fruits. Blossoms drop off; fruits develop dark, sunken and leathery spots on the stem end and finally rot it.

Treatments and controls:

Disease-resistant code: “LM”

  • When the symptoms appear in greenhouse condition, use vents and fans to provide air circulation to reduce the humidity level in the infected areas.
  • In an open field, planting with enough spacing between plants up to 3 feet depending on tomato variety to access air circulation. Maintain a parallel line for planting tomato plants and use staking if needed.
  • Avoid watering over the plant leaves to spread out the disease from one plant to another. You better use a drip irrigation system.
  • This is a seed-borne disease, so collect some resistant varieties from reputed sources.
  • The pathogen can survive in the soil for one year, so never planting at the same groundto the next year,ratherchange the field location.
  • Remove and burn the crop residue and plant debris to avoid the pathogen spreading out.
  • Apply calcium chloride spray as chemical treatment and spray both sides of the infected leaves.
  • You can also apply milk spray, garlic spray, apple cider, and vinegar mix totreat and control the outbreak of the pathogen.
Leaf Mold Resistant Tomato Varieties

10: Other Leaf Diseases

There have some several tomato leaf diseases which also affect tomato stems and fruits Such as:

  • Bacterial Speck (Leaf+Stem+Fruit)
  • Bacterial spot (Leaf+Stem+Fruit)
  • Bacterial Canker (Leaf+Stem+Fruit)
  • Early Blight (Leaf+Stem+Fruit)
  • Late Blight (Leaf+Stem+Fruit)
  • Mosaic Virus (Leaf+Fruit)
  • Sunscald (Fruit+Leaf)

To learn more of the following diseases read the common tomato fruit problems.


How to read tomato codes

Disease Resistance and Plant Growth Habit Codes

Conclusion:

Proper tomato care (including right seed selection, mulching, shading, pruning, watering and fertilizing) can reduce the risk into half of all the tomato leaf and other plant problems. But, some of the problems created due to environmental effects which you can’t control.

 Some diseases resistant varieties may found locally also help to solve the possible tomato leaf problems according to your geographic location. To learn more details about foliar diseases and problems you should contact your local extension office.


Read More:

*** 7 Basic Reasons Behind Common Tomato Plant Problems

*** 5 Common Tomato Stem Problems and Solutions

Sources and Citations:

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