Tomato Diseases
"From Anthracnose to Verticillium
Wilt"
If you follow good tomato gardening practices then tomato
diseases is a topic you can hopefully avoid.
Unfortunately conditions for growing tomatoes are never perfect and you may find yourself
saying, "what in the world is wrong with my tomatoes!"
Good tomato growing practices help prevent tomato diseases
Following these basic practices is always a good idea to promote
a healthy garden:
- Rotate your crops by not planting tomatoes in the same
soil where tomatoes, peppers, potatoes, eggplant have been
planted for at least two years.
- Stake and mulch tomato plants to keep foliage from being in
contact with the soil.
- If watering from overhead, do it early in the day to
allow the sun to dry the leaves.
- Use disease-free certified seed or treated commercial seed.
- Use fresh deep soil with good drainage.
- Inspect tomato seedlings before planting and destroy any
that show disease signs.
- Increase the amount of organic matter in the soil. In
particular, well rotted manure will increase fertility and
decrease nematodes.
- Use "green manure" nitrogen fixing legumes in the
off-season to increase fertility of your
soil for tomatoes.
- Use frost protection
techniques to avoid tomato diseases encouraged by too low temperatures.
- Follow my 5 Best
Tomato Growing Tips
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- Symptoms
- small circular, slightly sunken water-soaked spots that get
darker and deeper or ring markings
- A slightly soft decay occurs as the fungus spreads
- Lesions merge into a large rotted area
- This tomato disease infects both green and ripe fruit
Causes
- root disease survives in infested tomato plant
debris
- attacks ripe tomatoes
- encouraged by infertile soil, poor drainage
- Controls:
- enrich soil with organic mulches
- improve drainage
- rotate crops in 3- to 4-year cycles
- protect against rain splash
- dispose of diseased fruit
- dust with fungicides
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Tomato Plant Diseases
- Symptoms
- seedlings die or produce weak, stunted plants
- wilting, curling and browning of leaves
- leaf rolling
- later bird's-eye spots on fruit - whitish-brown
spots with a white halo and raised dark brown center
- Cause
- contaminated seedbed soil
- infected seeds
- Control
- one of the most difficult to control tomato diseases
- use only treated seed
- rotate crops
- don't add old tomato or potato fruits or their foliage into
soil
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Tomato Plant Diseases
- Symptoms
- Infected leaves show dark lesions
- Yellowing leaves
- Blossom drop
- small, dark, slightly raised dots with a water-soaked
border quarter-inch in diameter
- center of spot is slightly sunken with a rough
surface
- is similar to Bacterial Speck but actually a
different bacteria
- Causes
- ripe fruit is not affected
- may be carried by tomato seed
- carried by windblown soil or insects
- sometimes present on transplants produced in
southern U.S.
- spread by wind-blown rain
- Control
- same as for bacterial canker
- Use disease-free seed from western states or
hot-water treated seed
- rotate crops from year-to-year
- Apply a mixture of mancozeb plus copper during early
flowering and fruit setting periods
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Tomato Plant Diseases
- Symptoms
- Tomato disease with no visible spotting or yellowing of leaves
- Stems at ground level may be water-soaked and emit slimy ooze when pressed
- Often called brown rot
- rapidly kills entire plant
- Controls
- don't grow tomatoes in the same spot for 4 to 5
years
- Grow seedlings only in pasteurized soil
- destroy all diseased plants
- grow disease-resistant varieties like Venus
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Tomato Plant Diseases
- Symptoms
- Slight water-soaked spot near blossom end of fruit
- One of the most common tomato diseases
- Sunken spot turns flattened, black, and leathery
- Appears on first fruits
- Causes
- Moisture fluctuations
- Lack of calcium during drought spells
- Planting early in cold soils
- Soils contain excessive amounts of salts causing a
decrease in calcium availability
- Controls:
- Keep soil moisture constant with mulching and
consistent watering
- Soil should have good drainage
- Don't fertilize with too much nitrogen
- Test soil for calcium deficiency
- Don't cultivate too close to plant, thereby damaging
roots
- Use resistant varieties like
Marglobe
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Tomato Plant Diseases
- Symptoms
- Water-soaked brown or grayish-green spots near
blossom end
- Spots located where fruit touches the soil
- Causes
- A disease that only affects tomatoes
- Controls
- Have soil with good drainage
- Don't wet plants when watering
- Stake so fruits don't contact soil
- Don't plant tomatoes in same spot every year -
instead, rotate crops
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Tomato Plant Diseases
- Symptoms
- severe scarring at blossom end of fruit
- bands of scar tissue
- swollen bulges
- fruit puckering
- more severe on first fruits and large varieties
- Causes
- The flowers are harmed when very small
- temperatures are too cool
- Pesticide effects - particularly 2,4-D
- Controls
- Grow hybrids instead of heirloom varieties
- Plant later when warmer
- Use frost protection
of tomato plants in garden beds
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Tomato Plant Diseases
- Symptoms
- Another of the tomato diseases that causes yellow foliage
- Causes
- Excess lime
- Iron deficiency
- Controls
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Tomato Plant Diseases
- Symptoms
- Blemishes on green or ripe fruit
- Spots are one-eighth to one-quarter cream colored
spots
- As fruit matures spot color changes to yellow
- Causes
- Controls
- Use weed control strategies where stink bugs live
- Hand pick insects from plants
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Tomato Plant Diseases
- Symptoms
- Stunted growth of young plants
- One of many tomato diseases that is shared with
other plants
- Odd stringy shoestring-type leaves
- Causes
- Virus spread by aphids
- Not seed borne like tobacco mosaic
- Controls
- control aphids
- separate plants from nearby weeds, flowers,
cucumbers, melons, or peppers
- Keep virus hosts phlox, petunias, hollyhock and
zinnias at a distance
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Tomato Plant Diseases
- Symptoms
- This tomato disease exhibits leaves that are curly and twist upward
- Causes
- Is a virus spread by leafhopper insects
- Controls
- Eliminate leafhoppers
- Reduce plant spacing more than normal
- Don't plant beets nearby
- Plant late varieties rather than early varieties
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Tomato Plant Diseases
- Symptoms
- Seedlings rot away at the base
- Causes
- Controls
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Tomato Plant Diseases
- Symptoms
- A tomato disease typified by dead areas in leaves
that form along the leaf veins
- Brown streaks along main stem
- Dry shrunken spots on green fruits
- Causes
- Controls
- Suppress weed growth around tomato plants
- Avoid handling tobacco before handling plants
- Rinse your hands in a water/milk solution
- Spray plants with a 50-50 solution of water/milk
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Tomato Plant Diseases
Early blight is one of the
most severe tomato diseases affecting home gardeners and can affect the stems, leaves, and fruit of tomato plants.
It can also cause damping-off in seedlings. It doesn't occur
in arid dry regions but is most active in warm, wet or rainy
conditions. More about early
blight...
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Tomato Plant Diseases
- Symptoms
- Fungus occurring after soil temperature reaches 75-
to 85-degrees
- Yellowing and dying of lower leaves
- Eventually entire plant wilts
- Causes
- Fungal infection starting in roots which blocks
water and nutrient flow to plant
- Controls
- Rotate crop especially if disease occurred prior
years
- Buy or grow seedlings grown in sterile/clean soil
- Remove weeds from garden
- Grow resistant tomato varieties
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Tomato Plant Diseases
- Symptoms
- Fruit has small white circles surrounding a green
center
- First spots appear on shoulders of green tomatoes
- Causes
- Controls
- Avoid planting in cool, damp conditions
- Rotate crop every year
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Tomato Plant Diseases
- Symptoms
- Leaves have small gray-brown spots on underside
- In the U.S. this tomato disease is primarily a problem in Southeast
states
- Leaves turn yellow and drop off
- Causes
- Controls
- Destroy all infected plants at season end
- Plant resistant varieties
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Tomato Plant Diseases
- Symptoms
- First symptom is gray spots on leaves and black
marks on stems
- Occurs mainly in greenhouses
- Fruit has gray-green or gray-brown decayed spots
- Is a major cause of rot of plant produce in tomatoes
and other vegetables
- Causes
- Fungus Botrytis cinerea
- Airborne fungus attaches to injured tissues
- In greenhouses conditions of high humidity and cool
conditions predispose
- Controls
- Fungicides will help protect but will not suppress
and established infection
- Treat the crop with fungicides before infections
build up
- Lower humidity and raise temperature
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Tomato Plant Diseases
- Symptoms
- Blotchy ripe fruit
- Fruit has internal brown areas
- Causes
- Unknown, insufficient sunlight suspected
- Controls
- Plant in a sunnier spot
- Don't over-fertilize with nitrogen which promotes
excessive foliage cover
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Tomato Plant Diseases
- Symptoms
- Hard centers in ripe fruit
- Causes
- Temperature fluctuations, esp. low night
temperatures
- Controls
- Discourage this condition and other tomato diseases
by providing warmer, more consistent growing temperatures
using frost
protection techniques
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Tomato Plant Diseases
Late blight is a destructive
tomato and potato disease that is sometimes confused with early
blight, but is actually a very different pathogen. It
generally develops at cooler temperatures than early blight.
Pictures and more about late blight...
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Tomato Plant Diseases
- Symptoms
- Leaves have yellow or green spots
- Leaves have purple mold areas
- Causes
- Controls
- Don't irrigate in the evening
- Water plants at base, not overhead to avoid wetting
leaves
- In greenhouses, keep temperature above 60˚F (15˚C)
and humidity low
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Tomato Plant Diseases
- Symptoms
- Curling/rolling/dropping of leaves, usually stops
after temperatures rise
- Not one of the serious tomato diseases--usually
clears up once temperatures warm
- Causes
- Physiological disease
- Wet spring weather
- Poor soil drainage
- Close cultivation
- Over pruning
- Controls
- Plant in well-drained soil
- Use straw mulch
- Don't stake or prune plants
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Tomato Plant Diseases
- Symptoms
- Fruits have smallish tan or brown spots
- Causes
- See early blight for
causes and controls of this tomato disease
- Controls
- Plant resistant varieties
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Tomato Plant Diseases
- Symptoms
- Yellowing of younger leaves
- Wilting plants
- Purple streaks on stems
- Causes
- Virus transmitted from potatoes by aphids
- Controls
- Control aphids
- Don't plant tomatoes near potatoes
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Tomato Plant Diseases
- Symptoms
- Leaves have small 1/4-inch gray water-soaked spots
- Centers of spots have many dark brown, pimple-like
structures
- Spots appear on plant but rarely on fruit
- Infected yellow leaves are dropping from plant,
resulting in sunscalded fruit
- Causes
- Fungus
- Spread by windblown water, splashing rain, pickers
and beetles
- Rainy weather favors disease development
- Controls
- Keep garden weeds controlled and plant debris
removed
- Use only disease-free seed
- Use fungicides to control
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Tomato Plant Diseases
- Symptoms
- Fruits have small brown circular spots on lower half
- As fruits ripen, spots diminish but decayed areas
enlarge and split
- Causes
- A fungus harbored in the soil
- Controls
- Stake or cage plants, keep fruit off ground
- Remove any decayed or infected plant material
- Have well drained soil
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Tomato Plant Diseases
- Symptoms
- Rough textured yellow and green mottling of leaves
- Leaves brown and drop off
- Stunted plant and poor fruit yield
- Causes
- Most common virus affecting tomatoes
- Transmitted by aphids
- Remains in soil in weed roots
- High soil moisture
- Low nitrogen and boron in soil
- Controls
- Suppress weed growth around tomato plants
- Use disease-free certified seed
- Avoid handling tobacco before handling plants
- Rinse your hands in a water/milk solution
- Spray plants with a 50-50 solution of water/milk
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Tomato Plant Diseases
- Symptoms
- Yellow splotches on lower leaves later turning brown
- Lower leaves drop off plant
- Plant wilts during day and recovers at night
- Causes
- Common fungus living in the soil
- Dead stem tissue retards nutrients from roots
- Cool, moisture-saturated soil
- Controls
- Plant verticillium wilt-resistant varieties
- Keep garden free of weeds and remove plant debris
- Don't mulch tomato or potato plants - they can
harbor the disease
- Long crop rotation of four to five years with
nonrelated crops
- Well-drained soil
- Not over-watering
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Tomato Plant Diseases
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Other good web resources on tomato diseases
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