Tomatoes
Solanum lycopersicum
Popular warm-season fruit commonly grown as a vegetable
Growing Conditions
- Full sun
- Rich, well-draining soil
- Warm temperatures
- Support structure
- Regular watering
Common Problems
Blossom End Rot
Cause:
Calcium deficiency or irregular watering
Solution:
Maintain consistent moisture, add calcium
Organic Treatments:
Crushed eggshells or calcium spray
Synthetic Treatments:
Calcium nitrate (15.5-0-0 + 19% Ca)
Visual Description:
Dark, water-soaked spots appear at the bottom (blossom end) of fruits, starting small and enlarging to become brown to black sunken areas. The affected tissue becomes leathery.
Early Blight
Cause:
Fungal infection (Alternaria solani)
Solution:
Remove infected leaves, improve air circulation
Organic Treatments:
Synthetic Treatments:
Chlorothalonil fungicide
Visual Description:
Dark brown spots with concentric rings appear on older leaves first. Spots are irregular, up to 1/2 inch in diameter, and often have a yellow halo. Affected leaves turn yellow, wither, and drop. Disease progresses upward from bottom leaves. Stems can develop dark, sunken cankers. Fruit may develop leathery, dark spots near the stem.
Late Blight
Cause:
Fungal infection (Phytophthora infestans)
Solution:
Remove infected plants, use fungicides preventively
Organic Treatments:
Synthetic Treatments:
Visual Description:
Large, dark brown to purplish-black water-soaked patches appear on leaves, often starting at leaf tips or edges. White fuzzy growth may appear on leaf undersides in humid conditions. Stems develop dark brown to black lesions. Fruit develops large, firm, brown spots. Disease can destroy plants within days in wet weather.
Septoria Leaf Spot
Cause:
Fungal infection (Septoria lycopersici)
Solution:
Remove infected leaves, mulch to prevent splashing
Organic Treatments:
Synthetic Treatments:
Chlorothalonil fungicide
Visual Description:
Small, circular spots appear on leaves, starting with lower ones. Spots have dark borders and light gray or tan centers, about 1/8 inch in diameter. Tiny black specks (spore-producing structures) appear in spot centers. Affected leaves yellow and drop. Disease progresses upward through plant.
Tomato Hornworm Damage
Cause:
Large green caterpillars feeding on plants
Solution:
Hand-pick caterpillars, encourage natural predators
Organic Treatments:
Additional Controls:
Synthetic Treatments:
None - pest issue
Visual Description:
Large sections of leaves are eaten, often leaving only the main leaf stems. Damage typically starts at the top of the plant. Dark green or brown droppings can be found below feeding areas. The hornworms themselves are large (up to 4 inches), bright green caterpillars with white diagonal stripes and a horn-like projection on their rear end.
Leaf Roll
Cause:
Environmental stress or viral infection
Solution:
Maintain consistent moisture and temperature
Organic Treatments:
None needed - environmental issue
Synthetic Treatments:
None needed - environmental issue
Visual Description:
Leaves roll upward and inward, starting with lower leaves. Rolled leaves become thick and leathery but remain green. Plant may appear wilted even with adequate water. Growth may be stunted. If caused by virus, leaves may also show yellowing or mottling patterns.
Cracking Fruit
Cause:
Irregular watering or rapid growth
Solution:
Maintain consistent moisture, mulch soil
Organic Treatments:
None needed - water management issue
Synthetic Treatments:
None needed - water management issue
Visual Description:
Cracks appear on fruit surface, either radiating from stem (radial cracks) or circling fruit (concentric cracks). Cracks occur when fruit expands too quickly after rain following dry period. Cracked areas can allow entry of fungi and bacteria.
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