- Tomato Leaves Rolling?
- Physiological Leaf Roll
- Viral Infections
- Herbicide Damage
- So what causes these tomato plant problems?
- Nutrient deficiencies that cause pale or yellow leaves on tomato plants
- Yellow tomato leaves due to pests
- Yellow leaves with holes
- Yellow leaves and plants that wilt
- Yellow leaves with brown spots, mottled, or dappled appearance
- Leaf problems due to tomato plant diseases
- Tomato leaf problems you should not worry about
- Quick tips for dealing with tomato leaf problems.
- Bill Tyson: Are the leaves on your tomato plants rolling?
- 10 Tomato Plant Diseases to Watch For
- Septoria Leaf Spot
- Fusarium and Verticillium Wilt
- Early Blight (Alternaria)
- Late Blight
- Mosaic Virus
- Blossom Drop
- Blossom-End Rot
- Damping Off
- Tomato Bacterial Diseases
- Understand the Tomato Plant Disease Code
- Brown edges on tomato leaves
- Septoria leaf spot on tomatoes: More ways to prevent spots before your eyes
- How can I keep my tomatoes from getting leaf spots?
Tomato Leaves Rolling?
Curling or rolling of tomato leaves can be caused by various factors, including environmental stresses, viral infection, and herbicide damage. To determine which factor is the culprit, it pays to take a close look at the plant(s). Which leaves are rolling – old leaves, new leaves, all leaves? What direction do the leaves roll – upward or downward? Are any other parts of the plant, including fruit, exhibiting symptoms?
Physiological Leaf Roll
Tomato foliage is exhibiting physiological leaf roll.
Joey Williamson, HGIC Clemson University
Excessive moisture and nitrogen, heat, drought, severe pruning, root damage and transplant shock are some of the environmental factors that can cause physiological leaf roll in tomatoes. Initial symptoms are usually apparent in the lower leaves with an upward cupping of leaflets followed by an inward lengthwise rolling of the leaflets toward the mid-vein. The affected leaves tend to become thickened and have a leathery texture, but retain a normal, healthy green color. Over time all of the leaves on the plant may be affected.
Interestingly, vine tomato (indeterminate) varieties tend to exhibit physiological leaf roll more often than bush tomato (determinate) varieties. While this condition can occur at any time of the growing season, it usually occurs as spring weather shifts to summer. The good news is that the condition has minimal impact on tomato fruit production and plant growth. By properly hardening off tomato seedlings before planting in the garden, maintaining a consistent moisture level in the soil, and avoiding over fertilization, excessive pruning and root damage during cultivation, one can go a long way toward preventing tomato plants from developing this physiological problem.
The tomato is infected with Tomato yellow leaf curl virus and showing symptoms of cupped, pale green foliage.
David B. Langston, University of Georgia, United States
Some viral infections also cause leaf rolling in tomatoes. When tomato plants are infected with Tomato yellow leaf curl virus (transmitted by whiteflies), new leaves become cupped and pale green in color. In addition the entire plant may exhibit stunted growth, yellowing leaf edges, purplish veins on the undersides of leaves, and decline of fruit production. A second virus, Tomato mosaic virus, causes rolling of leaves, but other symptoms, including mottled-coloring of leaves, small leaflets, and internal browning of infected fruit, distinguish it from physiological or herbicide-induced leaf roll.
There is no treatment for virus-infected plants. Removal and destruction of plants is recommended. Since weeds often act as hosts to the viruses, controlling weeds around the garden can reduce virus transmission by insects. As some viruses are transmitted mechanically on garden tools, it also helps to disinfect tools that have come into contact with diseased plants.
Tomato plants are exhibiting damage from exposure to 2,4-D herbicide drift from nearby spraying.
Joey Williamson, HGIC Clemson University
When tomato plants are exposed to the herbicide, 2,4-D, typical symptoms include downward rolling of leaves and twisted growth. In addition, stems may turn white and split; fruit may be deformed. Depending on the level of exposure, the plant may or may not survive.
Herbicide injury cannot be reversed, but if the plant is not killed, new growth may be normal. Always be very careful when spraying an herbicide, as it may drift much further than anticipated.
To learn more about growing healthy tomatoes, as well as common tomato diseases and insect pests, see: HGIC 1323, Tomato; HGIC 2217, Tomato Diseases and HGIC 2218, Tomato Insects.
If you’ve ever grown tomatoes before, you’re probably familiar with tomato leaf problems. You might have noticed your tomato plant leaves turning yellow, brown, or getting spots.
So what causes these tomato plant problems?
We all love the flavor of a homegrown tomato. You just can’t get the same intensity and sweetness from any tomato at the grocery store. But homegrown tomatoes also come with lots of pest and disease issues.
The unfortunate reality is that tomatoes are susceptible to many pests and diseases. And many of them lead to yellow or brown spots on tomato leaves. Often you can determine the cause of the issue just by looking at the leaves.
The particular pattern of yellowing or spotting will give you lots of information about what disease or pest is plaguing your tomato plant. Use this guide to tomato leaf problems help you figure out what’s wrong and what, if anything, you can do about it.
Having troubles with your tomato fruit? Read this guide to tomato fruit problems.
If you’re a book person, you’ll love these resources for growing tomatoes that I keep in my garden library.
Organic Gardening For Dummies Rodale’s Ultimate Encyclopedia of Organic Gardening: The Indispensable Green Resource for Every… Epic Tomatoes: How to Select and Grow the Best Varieties of All Time – Organic Gardening For Dummies Rodale’s Ultimate Encyclopedia of Organic Gardening: The Indispensable Green Resource for Every… – Epic Tomatoes: How to Select and Grow the Best Varieties of All Time
There’s a lot of information in this article.
Feel free to read about all of them, but if it seems overwhelming, scan through the bolded words for the particular symptom you’ve noticed on your tomato plant and read just that section. And all the way at the bottom, I have some quick tips for dealing with tomato leaf problems.
Also, make sure you pin this article for later so you can refer back to it whenever you see tomato leaf issues come up.
Nutrient deficiencies that cause pale or yellow leaves on tomato plants
Whenever your plant’s leaves look pale, but the plant is otherwise healthy, try adding an organic liquid fertilizer first. Neptune’s Harvest is a reliable brand that we frequently use. Liquid fertilizer is more quickly absorbed, and you should notice improvement within a day or two.
Yellow leaves on tomato plant are often due to nutrient deficiency
Product Image Product Name Hydrolyzed Fish Fertilizer 2-4-1 Net Wt. 9lb Neptune’s Harvest FS191 Hydrolized Fish & Seaweed Neptune’s Harvest Tomato & Veg Fertilizer 2-4-2, 1 Gallon Product Rating Prime Eligible Product Image Product Name Hydrolyzed Fish Fertilizer 2-4-1 Net Wt. 9lb Product Rating Prime Eligible Product Image Product Name Neptune’s Harvest FS191 Hydrolized Fish & Seaweed Product Rating Prime Eligible Product Image Product Name Neptune’s Harvest Tomato & Veg Fertilizer 2-4-2, 1 Gallon Product Rating Prime Eligible
Whatever the deficiency, the liquid fertilizer should take care of it. But if you want to know exactly which nutrient is deficient, you might be able to figure it out by looking at the specific pattern of yellowing.
If you notice your young leaves (those at the top of the plant) are yellow with green veins, suspect iron deficiency. Check your soil pH to make sure it is between 6 and 6.8. If it’s too high, your tomato can’t take up necessary nutrients including iron.
If you notice older leaves (those at the bottom of the plant) are yellow with green veins, suspect potassium deficiency.
If you notice dark spots within the yellow areas and the leaves are small and narrow, you might have a zinc deficiency.
If young leaves are pale and the growing tips of your tomato plant die, suspect calcium deficiency.
Stunted plants with general yellowing of the leaves is an indication of nitrogen deficiency.
It’s best practice to have your soil tested to confirm nutrient deficiencies before adding anything other than organic fertilizer and compost.
Adding too much synthetic fertilizer can burn your plants, and overuse of lime and wood ash can alter your soil pH causing more problems with nutrients than they prevent.
Learn about using fertilizer in your veggie garden.
Yellow tomato leaves due to pests
Pests are a common cause of tomato leaf problems. They are often carriers of tomato diseases as well, so it’s prudent to keep an eye out for any insects on your tomatoes. Read about some of the bugs I’ve found in my tomatoes.
Aphids love tomato plants and cause yellow, misshapen, and sticky leaves. Look for tiny insects on the undersides of leaves and on the stem. These pests will suck the sap from your tomato plant and can be a real problem in any garden.
They can be many colors, but we often see the red/pink ones. Ants love the sticky substance they excrete, and you may have an issue with both insects at the same time.
There are several options for organic aphid control including neem oil and diatomaceous earth.
Brownish, finely dotted leaves with thin webs are an indication of spider mites. Look for tiny spider-like insects on your leaves that make fine webs between and below the leaves. Infested leaves will dry up and fall off.
Spider mites and aphids can be treated with diatomaceous earth (DE). DE is a natural substance that is readily available at local garden centers.
We use a plant duster like this one to apply diatomaceous earth to affected plants. This powder will cut through the aphids’ soft exoskeletons and cause them to dehydrate and die.
Rain and watering will negate the effect of the DE so reapply as needed. Be careful to use DE in well-ventilated areas as inhaling this powder can cause damage to your lungs. And the lungs of kids, pets, and chickens, too!
If they get really bad, other forms of organic pest control including insecticidal soaps and spinosad sprays can also help.
Yellow leaves with holes
Whenever you see holes in your tomato leaves, you should suspect insect damage. Colorado potato beetles, tomato hornworms, grasshoppers, and flea beetles are all common culprits. Remove and squish these pests when you see them and utilize organic pest control practices to manage them.
Yellow leaves and plants that wilt
There are several kinds of wilt caused by bacteria, fungi, nematodes, and toxins that can affect tomatoes. Regardless of the cause of the wilt, it’s best to remove severely affected plants from your garden and destroy them.
For mild infections, remove affected leaves (usually the lower leaves) and send them to the landfill or burn them in an area well removed from your garden. Do not compost diseased plants or leaves.
Fusarium and Verticillium wilt cause yellowing and wilting beginning with the lower leaves.
Tomatoes planted within about 50 feet of a black walnut tree, may suddenly wilt and die. This is caused a toxin secreted from the roots of black walnut trees and tree stumps.
Nematodes in the soil can infect the roots of your plants and cause wilt. If you pull up wilted plants and notice swollen sections in the root balls, nematodes may be the problem. Choose resistant varieties and/or add parasitic nematodes to decrease the incidence of disease.
There are many varieties of tomatoes that are documented to be resistant to various types of wilt. Look for resistance codes BFNV (Bacterial, Fusarium, Nematodes, Verticillium).
A note about resistance: don’t expect resistant varieties not to be affected by these diseases. Expect them to tolerate the disease. Remove and destroy affected leaves as they appear, and the plant should continue to produce fruit for you.
Yellow leaves with brown spots, mottled, or dappled appearance
Pale thin spots like the ones below are due to leaf burn. Leaves will experience sunburn when they haven’t been properly hardened off or when water droplets concentrate light on the leaves. If the burn is not too extensive, your plants will heal on their own and are not cause for concern.
Leaf problems due to tomato plant diseases
Tobacco Mosaic Virus
Dappled yellow leaves with twisty new growth are common with tobacco mosaic virus. This virus is often transmitted by insects and especially aphids.
Do not try to treat these plants. Destroy them and remove them from your property, and be sure to wash your hands after touching any plant you suspect could be infected with this virus.
When choosing tomato varieties for future gardening seasons, look for the TMV resistant label.
Bacterial Speck and Bacterial Leaf Spot
Small dark spots on leaves that then turn brown and fall off are a symptom of bacterial speck and bacterial leaf spot. These diseases thrive in hot, humid environments and can be transmitted by your hands and garden tools.
Be careful working with plants suspected to be infected with this disease. To prevent future issues, remove and destroy severely infected plants and choose varieties with BLS and PST resistance in the future.
Late Blight on tomatoes
Leaves develop brown patches that turn dry and papery when they become infected with late blight. Sometimes a white mold grows along the edges of the brown patches. If your tomato plants have late blight you will also notice blackened areas along the stems and the tomatoes develop hard brown lesions.
Late blight on a tomato plant.
Late blight will wipe out your tomato crop, and there is no treatment for infected plants. So try to prevent this disease by removing and destroying infected plants. Don’t compost them. Send them to the landfill and clean and remove all remnants of the infected crops from your garden.
Here’s a video from the University of Maine about late blight:
For future crops, try applying a preventative copper fungicide or Bacillus subtilis spray, make sure to water your plants at the base as wet conditions favor the spread of this disease, and look for resistant varieties labeled LB.
Septoria leaf spot has a similar appearance, but the brown patches are circular with light centers and dark specks. And the disease will start with the older leaves. Trim off infected leaves and remove them from your garden. Sanitize your hands after dealing with infected plants.
Early Blight on tomato plants
Early blight causes spots of dark concentric rings on leaves and stem of the lower plant first.
Early blight tends to strike your tomato plants when they’re loaded with fruit and days are humid and warm.
Preventative sprays may help slow the onset and spread of the disease, but infected plants should be removed and destroyed. Look for resistant varieties labeled AB (A for Alternaria fungal species) for future gardens.
Tomato Spotted Wilt Virus
Dark brown rings on the leaves can also be caused by tomato spotted wilt virus. In this disease process, you’ll also notice brown streaks on the stems, stunted or one-sided growth, and green rings on immature fruit.
This disease is spread by tiny flying insects called thrips. Check purchase plants carefully for signs of thrips and disease before bringing them home to your garden.
Practice good pest control and remove infected plants to control the spread of this disease. Resistant varieties are labeled TSWV.
Bacterial Canker disease on tomato plant leaves
Leaves with brown edges may be caused by bacterial canker. Lower leaves will also curl up and you may see light brown streaks on the stems of your plant. This disease often shows up after plants have been injured, so be careful when trimming your plants not to leave open wounds.
A note about disease resistance:
Don’t expect resistant varieties not to be affected by these diseases. Expect them to tolerate the disease. Remove and destroy affected leaves as they appear, and the plant should continue to produce fruit for you.
Tomato leaf problems you should not worry about
Tomato leaf curl is often an environmental change due to stress. With no other symptoms of disease, no treatment is necessary.
Purple leaves are caused by expression of anthocyanin due to light exposure. Often appearing on plants grown under intense light, there is no cause for concern or need for treatment of purple tomato leaves.
Phew! Did you make it through all of that?
Thanks for sticking around this long! There’s too much information to commit it all to memory, so here’s the take home message.
Quick tips for dealing with tomato leaf problems.
- Make sure your plants have adequate nutrients. Try an organic liquid fertilizer first.
- Check for pests on the stems and undersides of your tomato leaves. Remove them by hand and use organic pest control sprays retreating as needed.
- If you do find leaves that are yellow, wilted, or spotty. Remove them immediately and dispose of them in your trash. Wash your hands after you handle any plants you suspect may be infected with fungal, bacterial, or viral diseases.
- Plant resistant varieties remembering that even resistant plants can be affected by tomato plant diseases but will often continue to produce if cared for properly (remove infected leaves, water, fertilize).
- Severely affected plants should be removed from the garden and disposed of as soon as possible.
Last update on 2020-02-01 / Affiliate links / Images from Amazon Product Advertising API
Bill Tyson: Are the leaves on your tomato plants rolling?
I have been getting many calls about the leaves on homegrown tomato plants curling and rolling inward. Curling or rolling of tomato leaves can be caused by various factors including environmental stresses, viral infection and herbicide damage. To determine which factor is causing the problem, it pays to take a close look at the plant. Which leaves are rolling – old leaves, new leaves, all leaves? What direction do the leaves roll – upward or downward? Are any other parts of the plant, including fruit, exhibiting symptoms?
Excessive moisture and nitrogen, heat, drought, severe pruning, root damage and transplant shock are some of the environmental factors that can cause physiological leaf roll in tomatoes. Initial symptoms are usually noticed in the lower leaves with an upward cupping of the leaves followed by an inward lengthwise rolling of the leaflets toward the midvein. The affected leaves tend to become thickened and have a leathery texture, but retain a normal, healthy green color. Over time all of the leaves on the plant may be affected.
Indeterminate tomato varieties tend to exhibit physiological leaf roll more often than determinate tomato varieties. Some varieties are more sensitive to leaf roll than others, but none are completely resistant to this problem. The symptoms on tomatoes are very similar to those of a virus disease of potatoes that is known as leaf roll, but the leaf roll of tomatoes is not caused by virus infection. While this condition can occur at any time of the growing season, it usually occurs in late spring or early summer. The good news is that the condition has little impact on tomato fruit production and plant growth.
Suggested control practices which may help avoid or reduce leaf roll in tomatoes include:
• Plant tomatoes in a well-drained soil.
• Fertilize according to soil test recommendations and do not over fertilize (especially with nitrogen).
• Avoid deep and close cultivation – especially in dry weather.
• Maintain uniform soil moisture by watering plants during dry periods.
• Mulch your tomato plants.
There are a couple of other issues that can cause your tomato leaves to roll. The first is viral infections. There is no treatment for virus-infected plants. Removal and destruction of plants is recommended. The second issue is herbicide injury. When tomato plants are exposed to the herbicide 2,4-D, typical symptoms include downward rolling of leaves and twisted growth. In addition, stems may split and fruit may be misshapen. Tomatoes are very sensitive to 2,4-D. Depending on the level of exposure, the plant may or may not survive. Always be very careful when spraying a herbicide as it may drift much further than anticipated.
Bill Tyson is the coordinator for Effingham County Cooperative Extension of the University of Georgia. Email him at [email protected] or call the Extension office at 754-8040.
10 Tomato Plant Diseases to Watch For
From containers to expansive garden plots, growing tomatoes is a popular and relatively easy way to harvest at least some of your own produce. In fact, tasty and easy-to-grow tomatoes are the most popular garden vegetable. However, tomato pests and diseases such as tomato wilt can harm your crop. Don’t let those potential problems scare you away. Growing healthy, pest- and disease-free tomato plants is relatively simple. Keep your plants healthy by rotating crops, planting disease-resistant varieties, spacing plants properly, mulching, and watering at least 1 inch per week.
As tomato plants grow, keep an eye out for tomato pests and tomato plant diseases such as tomato wilt that may come in the form of fungi, bacteria, or viruses. In the fall, if you have had tomato plant disease problems or tomato pests of any kind, remove the entire plant. Rotate tomatoes so they grow in the same ground only every four years or so. Many tomato plant diseases and tomato pests lurk in the soil.
Related: Guide to Starting Tomatoes
Septoria Leaf Spot
Septoria leaf spot is one of the most common tomato plant leaf diseases. You can first detect this fungus as it creates a small, circular spot with a grayish-white center and dark edges. Small black spots may show up in the center. Affected tomato plant leaves turn yellow, wither, and fall off. Long periods of warm, wet weather contribute to this tomato plant disease, and splashing water spreads spores to other leaves.
Control leaf spot by not crowding your tomatoes. Leave enough space so air circulates and dries leaves. Avoid overhead watering. When watering tomatoes, water at the base of the plant. Also, water in the morning so wet leaves have time to dry before evening. A fungicide formulated for tomatoes can be used to treat affected plants.
Follow the same procedures used for septoria leaf spot against the tomato plant disease anthracnose. This fungus shows up as a small, circular, indented area on tomato fruits. Eventually, rings surround the original spot. The flesh of the fruits may rot completely through, especially on overripe tomatoes, so keep fruits picked as they ripen. Spores are spread by rain splash, and the fungus is most common in warm, wet weather.
Related: Heirloom Tomato Varieties
Fusarium and Verticillium Wilt
These tomato plant wilt diseases are caused by fungi in the soil that enters through young roots, then begin to plug the vessels that move water to the roots and stems of the plants. Without water, the plants begin to suffer from tomato wilt on sunny days, although they appear to recover at night. Tomato wilting may first appear in the top or lower leaves of the plant, causing them to lose color, then die back from the tips. The process of tomato wilt continues until the entire plant is affected.
Heirloom tomato varieties that have not been bred to withstand these diseases are commonly attacked by tomato wilt. New strains of this tomato plant disease attack cultivars that are resistant to only one type of tomato wilt. Fusarium wilt is most common as a tomato plant disease in warm-weather regions and occurs during the warmest weather in cool areas.
To avoid these tomato plant diseases, plant tomatoes bred for disease resistance. They should be labeled V (for verticillium), F, FF, or FFF (for fusarium variations). Avoid overwatering tomato plants; just because a plant is wilted doesn’t mean it needs more water. Check the soil; if the soil is dry, then water the plant.
If your tomatoes are affected by one of these tomato wilts, remove and destroy all affected plants. Do not place them in your compost pile. Avoid using this location for tomato, eggplant, potato, and pepper plants for four to six years, because the fungi that cause the tomato wilt remain in the soil. Corn and beans won’t be affected. Keep weeds out of affected areas because their roots can continue feeding these pathogens.
Early Blight (Alternaria)
Another tomato plant disease fungus, Alternaria, also causes leaf spot or early blight. Lower leaves show brown or black spots with dark edges, almost like a target. Stem ends of fruits may be attacked, showing large, sunken black areas with concentric rings. This tomato plant disease fungus usually strikes after plants set fruit.
The tomato plant disease late blight, caused by the fungus Phytophthora infestans, occurs during periods of cool, rainy weather that may come at the end of a growing season. It looks almost like frost damage on leaves, causing irregular green-black splotches. Fruits may have large, irregular-shaped brown blotches that quickly become rotten. This tomato plant disease fungus also affects potatoes and can be transferred from them. Use the same controls as for septoria leaf spot.
Mosaic virus attacks many kinds of plants and is common in tomatoes. While mosaic virus doesn’t kill the plant, it diminishes the number and quality of fruits. The virus gets its name from the markings that resemble a mosaic of light green and yellow on the leaves and mottling on the fruits of affected plants. Leaves may also grow in misshapen forms, resembling ferns.
Because the virus must enter through a cut in the plant, avoid handling the plant. Anyone who uses tobacco can easily transmit the disease; wash hands thoroughly with soap to cut the risk of infection. Avoid this virus by planting resistant cultivars and not replanting in areas that previously hosted the problem.
Brought on by temperature extremes, blossom drop occurs when temperatures rise above 85 degrees F or drop below 58 degrees F. The temperature extremes cause tomato plants to discard their developing blossoms. Often, the damage is not realized until harvest is reduced later in the season.
Prevent blossom drop by using row covers to raise night temperatures. Little can be done to thwart high daytime temperatures. Maintain healthy plants so they will set new buds after the heat wave passes.
Related: Tips for Growing Healthy Tomatoes
Caused by a lack of calcium, most often brought on by fluctuating water availability, blossom-end rot is a common tomato disorder. It appears as a sunken, dead area opposite the stem (the blossom-end of the fruit). The area will expand as the fruit matures.
Prevent blossom-end rot by promoting steady, stress-free plant growth. Water plants regularly to maintain moist, but not waterlogged, soil. Spread a 2-inch-thick layer of mulch around plants to conserve soil moisture.
A frustrating fungal disease, damping off causes sudden collapse of seedlings, or failure to germinate. There are many steps you can take to prevent damping off. First, plant seeds when soil is at optimum temperature. Presoak seeds to speed germination. If planting seeds in potting mix, use sterile potting soil and containers. Allow the soil to dry between waterings.
Essentially a sunburn on a tomato, sunscald causes a section of the fruit to become soft, light in color, and dry. Prevent sunscald by maintaining enough foliage to shade fruits or shade fruits artificially with a shade cloth.
Related: Tips for Growing Heirloom Tomatoes
Tomato Bacterial Diseases
Tomatoes can fall prey to a number of tomato plant bacterial diseases, including bacterial spot, bacterial speck, and bacterial canker. They’re all slightly different but appear as spots on leaves and fruits. Use the same controls as for septoria leaf spot. Grow disease-resistant plants. Avoid rotating the same ground with peppers, which can host the same diseases. Avoid pruning and tying plants, because the bacteria can enter any openings made during these procedures. Fixed copper sprays may reduce the spread if applied as soon as symptoms begin.
Understand the Tomato Plant Disease Code
Disease resistance has been bred into many tomato varieties. The letters behind the names are codes showing what diseases and insects the tomato plants are bred to resist, including:
V Verticillium wilt
F Fusarium wilt
F Fusarium wilt races 1 and 2
FFF Fusarium wilt races 1, 2, and 3
A Alternaria alternata (stem canker or early blight)
T Tobacco mosaic virus
St Stemphylium (gray leaf spot)
TSWV Tomato spotted wilt virus
For example, the label on Big Beef VFFNTA Hybrid, a winner of a 1994 All-America Selections award, tells you that it is bred to resist verticillium wilt, fusarium wilt races 1 and 2, nematodes, tobacco mosaic virus, and Alternaria, and early blight.
- By Deb Wiley
If you’ve ever grown tomatoes, then you’ve probably had to contend with tomato plant diseases. It’s easy to think of tomatoes as easy-to-grow garden vegetables, but that isn’t always the case. In fact, tomatoes can be pretty picky about their soil nutrients, water levels, and the way they’re spaced in garden beds. There are a lot of different diseases that can strike your plants, and sometimes I feel like I’ve seen them all in my own home garden. Learn how to identify the most common tomato plant diseases, and how to both avoid them and treat them effectively.
Photo credit: Wikimedia Commons
Many tomato gardeners get frustrated when early blight (Alternaria solani) strikes their plants. As the name suggests, this disease afflicts on tomato leaves early in the growing season, and can cause trouble all season long if you don’t act quickly. This affliction first appears as little brown spots on the the plant’s leaves, which then spread outwards and become a lot more noticeable. Eventually, the infected leaves will fall off the plant.
Alternaria sp. is a tough fungus that can survive in soil even over the winter. The easiest way to prevent it is to mulch your tomato plants immediately after planting, which prevents the spores in the soil from creeping up and infecting your plants. When you see tomato blight, snip off infected leaves to prevent it from spreading. Next year, plant your tomatoes in an unaffected area of the garden.
Photo credit: Wikimedia Commons
One of the most common tomato diseases—septoria leaf spot—appears just as its name suggests. This disease, shown here on wheat leaves, covers your tomato leaves with small, circular spots that have gray-white centers and darker edges. You’ll see this issue most often when the weather has been warm and wet.
Septoria (Septoria tritici) may look fairly harmless, but it will destroy your plants’ foliage. Leaves turn yellow, then wither away and fall off.
Prevent leaf spot by keeping a neat, tidy garden. Don’t place your tomato plants too close together, so air can circulate around the leaves. Since this filamentous fungus thrives in wet soil, you can avoid it by not overwatering. If leaf spot does appear, cut the infected leaves off your plants to slow the disease from spreading. Make a note of this issue in your gardening journal, and don’t grow tomatoes in the same soil next year. If the affliction persists, you’ll need to use fungicide to kill the spores, and/or dig out the beds and replace the soil entirely.
Photo credit: Flickr
Fusarium wilt (Fusarium oxysporum) is most commonly found in southern U.S. states, but it can occur anywhere. When it does, it’s capable of wiping out entire tomato fields. It starts with drooping stems, but from there it progresses to an all-over wilting, and eventual total collapse. If you suspect you’re dealing with this type of fungus, cut the main stem of your tomato plant open, and look for the hallmark dark streaks running lengthwise through the stem.
This disease can be a huge problem, because the pathogen’s spores can remain dormant in soil for years. Once active, they can (and will) spread easily to other garden areas, too. You can try to prevent it by disinfecting tomato cages and stakes at the end of every growing season. Use a mixture of 1 part bleach to 9 parts water to clean these items to disinfect them completely.
Once your soil is infected with Fusarium, it’s extremely difficult to get rid of. Rotate your crops to keep tomatoes away from infected soil, and look for wilt-resistant tomato varieties when you’re shopping for new garden plants.
Photo credit: Wikimedia Commons
When you see little sunken areas starting to appear in your tomato’s leaves, you’ll know they have a case of anthracnose. This fungal pathogen is one of the most common tomato plant diseases, and is caused by Colletotrichum phomoides fungus. It is extremely common, and it will eventually rot the entire plant, including the fruit. Anthracnose thrives in hot, wet weather, and can also afflict potatoes and onions.
Protect your plants from anthracnose by removing leaves from the plants’ lower 12 inches. This keeps foliage from coming into contact with wet soil, which encourages the growth of this fungal disease. One way to avoid this fungus is to refrain from over-watering your tomato plants.
You can also fend it off by rotating crops with those that aren’t members of the nightshade (Solanaceae) family, preferably every other year. So, if you plant tomatoes in your garden this year, avoid growing tomatoes, peppers, and eggplants in that spot next season. Try carrots, beets, and other root vegetables instead.
Blossom End Rot
Photo credit: Flickr
Do your tomatoes have dark spots on their bottoms? If they do, you’re probably dealing with blossom end rot. This common disease is usually caused by soil that is deficient in calcium. It can also appear if tomatoes have been planted in alkaline soil, or have been watered unevenly. You can easily prevent this disease by enriching your soil with calcium, and watering regularly and evenly. If your tomato plants are having problems with drying out, use mulch to help keep the soil moist.
Be sure to test your soil’s pH level as well! Tomatoes thrive in soil that has a pH level of 6.0-6.5. If your garden beds are too alkaline, you can add sphagnum peat or other amendments to make it more acidic.
If you see blossom end rot in your tomatoes, simply remove the fruits that have been affected. This can help new fruits grow disease-free.
Photo credit: Wikimedia Commons
Look for powdery mildew on your tomato plants in late summer and fall, or if you grow your plants inside a greenhouse. It appears on leaves as discolored, yellowish spots that have a fuzzy, powder-like substance on top of them. This will eventually progress to brown, dead areas all over the leaves.
Powdery mildew is also among the most common tomato plant diseases. It often shows up during periods of high humidity, or inside greenhouses (which are usually quite humid). In fact, there are three different types of powdery mildew that can afflict your plants: Leveillula taurica, Erysiphe orontii, and Oidium neolycopersici. Once these fungi show up, they can spread quickly.
Neem oil has proven to be effective at treating powdery mildew, as has sulfur. If the mildew has spread to several plants, a more widespread fungicide treatment might be needed. You can avoid this issue by spacing your plants well apart, and watering the soil at ground level, rather than pouring water over the leaves from above.
Photo credit: Wikimedia Commons
If the edges of your tomato leaves turn brown, and yellowish closer to the center of the foliage, they have bacterial canker (Clavibacter michiganensis pv michiganensis). It usually appears on only on side of a tomato plant. Bacterial canker is a huge problem in the garden, because it’s one of the most difficult tomato plant diseases to treat. It spreads quickly to other plants, and will eventually cause them to wilt and die.
Since this issue is often seed borne, make sure to buy heirloom, organic seeds from trusted companies. Should bacterial canker strikes, move healthy plants to a new area of the garden, and treat the afflicted plants with copper hydroxide or streptomycin spray. As a preventative measure, don’t plant your tomatoes in the same spot next year. In fact, keep tomato plants out of the area for at least three years so the disease won’t make a comeback.
Photo credit: Wikimedia Commons
If your tomato fruits are cracking, you’re dealing with a common problem that’s not quite a disease—but is definitely an illness. Fruit cracking is caused by insufficient light, water, temperature, or nutrients in tomato plants, which basically creates traumatized fruit.
You can prevent cracking fruit by growing tomato plants in raised garden beds that allow you to control the moisture levels of the soil. Use compost and mulch to maintain more constant soil moisture, and make sure your soil has plenty of calcium. Remove cracked fruits the minute you see them to avoid pest problems, since ants and other insects will be drawn to the exposed flesh within.
Photo credit: Wikimedia Commons
Don’t let the name of this disease fool you. Verticillium wilt doesn’t always cause wilting, but tomato leaves will become yellowish and dry when it strikes. This fungal disease can affect other garden plants in addition to tomatoes, which makes it particularly virulent. Since it affects the plant’s xylem vascular tissues, wilt makes it difficult for tomato plants to get water and nutrients from the soil. Deprived of both food and water, the plant eventually dies.
You’ll notice this disease most often in cool weather conditions. If verticillium wilt has affected your tomatoes, move healthy plants away from this area of the garden and don’t plant new ones there for at least four years. Avoid planting other nightshades such as peppers, eggplant or potatoes in that spot in future, or they might succumb to wilt as well.
Photo credit: Wikimedia Commons
Late blight is named not for the time of year it appears in the garden, but for the part of the tomato plant it strikes first: the oldest. The most mature leaves will be the first to develop this issue, which appears as misshapen, greenish-black patches on leaves. This blight grows on foliage quickly, and spreads throughout the garden if it’s not addressed.
Once late blight strikes tomato plants, remove and destroy all infected plants and move healthy ones to a new area of the garden. Don’t plant any other nightshades in this soil for at least four years.
Heal Your Garden
Hopefully this article will help you to identify common tomato plant diseases, avoid them, and treat them effectively if they appear in your garden. Once you know how to manage these issues, you’ll end up with healthy, beautiful plants, and delicious fruit.
Don’t let those potential problems scare you away. Growing healthy, pest- and disease-free tomato plants is relatively simple. Keep your plants healthy by rotating crops, planting disease-resistant varieties, spacing plants properly, mulching, and watering at least 1 inch per week.
Start your tomatoes off right.
As tomato plants grow, keep an eye out for tomato pests and tomato plant diseases such as tomato wilt that may come in the form of fungi, bacteria, or viruses.
Get tips for growing healthy tomatoes.
In the fall, if you have had tomato plant disease problems or tomato pests of any kind, remove the entire plant.
Rotate tomatoes so they grow in the same ground only every four years or so. Many tomato plant diseases and tomato pests lurk in the soil.
Brown edges on tomato leaves
To answer to your first question about layout; I had written that suggestion in my remarks yesterday but deleted it because in some of your pictures I saw that you had already tried it. It seems to work on paper. How does it feel to you? Regarding the drapes . . . this is something I struggle with myself. I don’t think I’m good with color. I tend to be very monochromatic and I think you may be too. When I see professionally decorated rooms with coordinating colors and fabrics I think they’re beautiful and often stunning. But I don’t seem to have that knack. My mother was an interior designer but I didn’t inherit that gene. I’m better at picking out a 2×4 and building things. I love construction! I think kitchens and bathrooms are so much easier than living rooms and bedrooms. Back to your window coverings – My mother said something like, "If you were putting together an outfit to wear; would you wear these two fabrics together?" So . . . would you? To illustrate my point I’ve included this photo of a Roman shade I made. I have two other windows in the room with the same Roman shade that I want to add drapery panels to so I brought home many fabric samples and asked myself the question, "If that shade was a blouse would I wear any of these "jackets" with it?" The answer was "Eeeeeeewww! No!" and I eliminated all but two. You asked about ivory, beige or brown drapery. Personally I think ivory and beige would be boring. We tried that in our room and just thought . . . nah. In my opinion the dark brown would be too strong. You also asked about painting the wall around the big window blue. I think all blue would be better than an accent wall. Be careful if you do. I’m a Realtor and I’ve never seen a good blue wall yet. I don’t know what people are thinking . . . They end up with painters-tape blue, blue-tarp blue, swimming pool blue, all of which are hideous on the walls. However, since I said the people in my area chose ghastly shades of blue, I found these photos of tasteful blue rooms. How about this room? It has some of the blues you like but no blue walls. This one has very pale blue walls with the dark brown furniture and beige carpet. This one is all blue, not just one wall. BTW – your room turned out lovely, such an improvement over what you started with. Replacing the slider with the big window was smart. TF
Septoria leaf spot on tomatoes: More ways to prevent spots before your eyes
Editor’s note: Tomatoes are susceptible to several diseases in the summer. To help you identify whether your tomatoes are infected with Septoria leaf spot or another disease, see the tip sheet “Tomato Diseases in the Home Garden.”
Tomatoes are one of the favorite fruits or vegetables gardeners grow every year. They are unique in several respects. Botanically, the tomato is a fruit. It is classified as such because the portion that is eaten contains reproductive structures (seeds). However, in 1893, the tomato was declared a vegetable by the United States Supreme Court. The reason involved the collection of import duties. So, the tomato is either a fruit or a vegetable, depending on whose definition is used.
The tomato was called the “love apple “and believed to be poisonous until around 1850. It was only grown for its attractive but forbidden fruits. Because it is in the same family as nightshade, it was considered unsafe for human consumption.
Regardless of its interesting history, almost all gardeners include a tomato or two for their eating pleasure. Michigan summers with their warm and often humid climate are favorable for various leaf blights to develop. One of the common tomato maladies is Septoria leaf spot. It is a fungal disease that affects the leaves, but not the fruit. The first leaves that are affected are typically toward the bottom of the plant. The leaves develop small, dark spots that rapidly enlarge to 0.25 inches and have a tan or gray center. There may be small, black dots, which are the fruiting bodies of the fungus, located in the center of the spot. If there are enough spots, the leaves turn yellow, then brown. The leaf eventually wilts, dries up and falls off. The Septoria pathogen will then spread via water splashing to the upper leaves causing defoliation further defoliation. Michigan State University Extension hotlines are just beginning to answer questions about Septoria now.
Left, Signs of Septoria leaf spot on a tomato leaf. Photo credit: William M. Brown Jr., Bugwood.org.
Right, Leaf spotting and advanced decay of Septoria leaf spot. Photo credit: Paul Bachi, Univ. of Kentucky Research and Education Center, Bugwood.org
Septoria can be prevented but not cured once it is evident. If Septoria has been a problem on tomatoes in previous years, it may become an issue in subsequent years especially if the tomatoes are always planted in the same garden spot each year. The pathogen survives best on tomato foliage but may also infect Solanceous weeds related to tomatoes like Jimson weed, horse nettle, ground cherry and nightshade. When conditions are wet, spores are exuded from the Septoria fruiting bodies present on the infected tomato leaves. Once the spores land on a healthy leaf, spotting can appear in five days if weather conditions are ideal.
There are a number of cultural techniques that can be used to limit Septoria. Picking off the spotted leaves can slow down the disease if the infection is fairly light. Growing tomato plants in containers can be especially helpful provided that the soil used in the container is not from the garden. Using a commercially available bagged potting mix assures you that you’ll be starting your plants in a fresh environment free of residual Septoria. Remember to stake and space the tomato plants so that air can move freely within the foliage so that the time that the tomato leaves are wet is minimized. Water the plants via trickle irrigation so as to keep the foliage dry. If watering the plants overhead, do it at a time of day that allows the foliage to dry quickly. Avoid watering the plants in the evening as that might allow the leaves to stay wet through the nighttime and that will favor disease. If your garden is large enough, rotate your tomato plants so they are not grown in the same spot each year. At the end of the season, remove any infected tomato debris and dispose of it (do not compost it).
If despite your best efforts, Septoria continues to make a yearly appearance in your garden, you may want to consider using a protectant fungicide. One of the most common fungicides used for tomato spots/blight is chlorothalonil which can be found in several brands. There is now an organic fungicide called “Serenade” that can also be used. It may be difficult to find unless there are local businesses that carry organic products or it may have to be purchased online. Always read and follow all the label directions. It usually indicates that the spray is repeated at seven- to 10-day intervals during the growing season to protect the plant. During rainy periods, the interval between the sprays may need to be shortened. (i.e., applications made every 7 days versus 10 days). However, pesticide sprays cannot be applied more frequently than what is specified on the label.
By following these growing strategies you should be able to minimize Septoria leafspot. Your bacon, lettuce and mayonnaise will thank you.
Thanks to MSU plant pathologist Mary Hausbeck for review and input to this article.
How can I keep my tomatoes from getting leaf spots?
Fungal leaf spots can be a serious problem in home vegetable gardens, reducing yields and impacting fruit quality. Two common fungal diseases are early blight and Septoria leaf spot. In order to prevent your tomatoes from getting these diseases and to effectively treat them, you must understand the disease cycle of each fungus as well as identify which disease is causing symptoms in order to manage it successfully.
Early blight can damage both tomato foliage and fruit. Leaf spots develop on the older leaves of the plant, towards the bottom, and move upward to new growth as the disease progresses. The spots initially look like irregular circles. As times goes on, concentric rings form around each lesion, giving them a ring pattern with a distinctive yellow halo. Dark, sunken cankers can also develop on the stems and fruit.
Septoria leaf spot also develops first on the older, lower leaves and can cause complete defoliation in a relatively short period of time. Symptoms include many small, circular, dark spots on the leaves that have grayish centers and dark brown margins. The spots may eventually develop yellow halos as the leaves wilt and die.
Septoria leaf spots develop on the older, bottom leaves first. Spots look like dark, irregular circles.
Early blight and Septoria leaf spot overwinter in garden soil and crop debris, and infect plants when growing conditions are right. To prevent these diseases, start by thoroughly removing and discarding crop debris at the end of the season. If possible, rotate where you plant tomatoes and related plants (peppers, eggplants, potatoes) each year. Multiyear rotations help limit infection because susceptible plants are kept away from soil-borne fungi. You should also always use disease-free seeds and transplants, as well as disease resistant cultivars, of which there is a growing number to choose from. While it may be too late for these actions to solve disease problems this year, keep them in mind for future years.
Next, make sure tomatoes are grown in a location with full sun and good airflow, as moist and humid conditions encourage fungal growth. Proper staking and pruning will improve air circulation and reduce disease issues. In concert with this, water in the morning if overhead sprinklers are used to allow leaves time to dry throughout the day. Even better, avoid wetting leaves entirely by using soaker hoses or drip irrigation. Consider mulching the soil beneath your tomatoes to prevent soil (and fungal spores) from splashing onto leaves, stems and fruit. Mulch will also help conserve soil moisture and prevent weed growth.
Removing the bottommost leaves from plants may also help prevent infection, as will the application of appropriate preventative fungicides. When using pesticides, always read and follow the label instructions. If you do notice leaf spots on your tomatoes, removing infected leaves will help decrease the number of spores that can cause new infections.
If you think your tomato plants may have a fungal disease problem, Ask UNH Extension or submit a sample to the UNH Plant Diagnostic Lab.
Top Picture: Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org
Bottom Picture: Nancy Gregory, University of Delaware, Bugwood.org
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