Plant Problems – rootanswers.garden

Problem	Category	Plants Commonly Affected	Symptoms	Cause	Organic Treatment	Prevention
Aphids	Pest	Most plants; roses, kale, peppers	Clusters of tiny soft insects on new growth; sticky residue; curled leaves	Sap-sucking insects, worst on tender new growth	Strong spray of water; insecticidal soap; neem oil	Avoid excess nitrogen; encourage ladybugs and lacewings
Tomato Hornworm	Pest	Tomato, pepper, potato	Large green caterpillars; leaves stripped overnight; dark droppings	Larva of the sphinx moth	Hand-pick; Bt (Bacillus thuringiensis) spray	Check plants weekly; leave hornworms carrying white wasp cocoons
Squash Vine Borer	Pest	Zucchini, squash, pumpkin	Plant wilts suddenly; sawdust-like frass at the base of the stem	Moth larva tunneling inside the stem	Slit stem and remove larva, then bury the stem; Bt injected into stem	Row cover until flowering; plant a second crop in midsummer
Cabbage Worm	Pest	Kale, collards, cabbage, broccoli	Ragged holes in leaves; green caterpillars; white butterflies nearby	Larva of the cabbage white butterfly	Hand-pick; Bt spray	Floating row cover from planting day
Slugs and Snails	Pest	Hosta, lettuce, strawberry, seedlings	Irregular holes; silvery slime trails; damage appears overnight	Feed at night in damp, shaded conditions	Iron phosphate bait; hand-pick at night; beer traps	Water in the morning; clear debris and boards near beds
Spider Mites	Pest	Tomato, beans, roses, houseplants	Fine yellow stippling on leaves; webbing underneath; worse in hot dry spells	Tiny mites that thrive in heat and dust	Hose off leaf undersides; insecticidal soap; neem oil	Keep plants watered; avoid dusty conditions
Whiteflies	Pest	Tomato, hibiscus, citrus, peppers	Cloud of tiny white insects when plant is disturbed; sticky leaves	Sap-sucking insects common in warm zones	Yellow sticky traps; insecticidal soap; neem oil	Inspect new plants before bringing them home
Japanese Beetle	Pest	Roses, beans, zinnia, many others	Leaves skeletonized to a lace pattern; metallic green-bronze beetles	Adult beetles feeding in early to midsummer	Hand-pick into soapy water in the morning	Skip pheromone traps near the garden; they draw in more beetles
Powdery Mildew	Disease	Squash, cucumber, zinnia, roses	White powdery coating on leaves	Fungus favored by warm days, cool nights and crowded plants	Remove worst leaves; potassium bicarbonate or neem spray	Space plants for air flow; choose resistant varieties
Early Blight	Disease	Tomato, potato	Brown spots with target-like rings on lower leaves, moving upward	Soil-borne fungus splashed onto leaves	Remove affected leaves; copper fungicide	Mulch; water at the base; rotate crops every 3 years
Late Blight	Disease	Tomato, potato	Large greasy gray-brown patches; white fuzz underneath; rapid collapse	Water mold that spreads fast in cool, wet weather	Remove and bag plants; do not compost	Resistant varieties; good spacing; avoid overhead watering
Black Spot	Disease	Roses	Black spots with fringed edges; leaves yellow and drop	Fungus spread by splashing water	Remove fallen leaves; neem or sulfur spray	Water at the base; prune for air flow; resistant varieties
Root Rot	Disease	Rosemary, lavender, houseplants, many others	Wilting even when soil is wet; mushy brown roots; yellowing	Fungi in waterlogged soil	Cut away rotted roots; replant in fresh, well-drained mix	Let soil dry between waterings; use pots with drainage holes
Damping Off	Disease	Seedlings of any kind	Seedlings pinch at the soil line and fall over	Fungi in cool, wet, stale conditions	No cure; discard and restart	Sterile seed mix; bottom-water; run a small fan
Fusarium / Verticillium Wilt	Disease	Tomato, pepper, strawberry	One side of plant yellows and wilts; brown streaks inside stem	Soil fungus that blocks water flow	No cure; remove plant	Varieties labeled V or F resistant; rotate crops
Citrus Greening (HLB)	Disease	Citrus	Blotchy yellow leaves; lopsided, bitter fruit that stays green	Bacteria spread by the Asian citrus psyllid	No cure; contact the county extension office	Buy certified disease-free trees; control psyllids
Blossom End Rot	Nutrient / Watering	Tomato, pepper, squash	Dark, sunken, leathery patch on the bottom of the fruit	Calcium not reaching fruit, usually from uneven watering	Remove affected fruit; water deeply and evenly	Mulch; steady watering schedule
Yellowing Lower Leaves (nitrogen)	Nutrient / Watering	Most vegetables	Older leaves turn pale yellow first; slow growth	Nitrogen deficiency	Compost or a balanced organic fertilizer	Add compost before planting each season
Yellow Leaves with Green Veins (iron)	Nutrient / Watering	Blueberry, azalea, hydrangea, citrus	New leaves yellow while veins stay green	Soil pH too high, locking up iron	Chelated iron; lower pH with sulfur	Test soil pH before planting acid-loving plants
Overwatering	Nutrient / Watering	Any, especially containers	Yellow, limp leaves; soggy soil; fungus gnats	Roots starved of oxygen	Let soil dry out; improve drainage	Check soil 2 inches down before watering
Bolting	Environment	Lettuce, spinach, cilantro	Plant sends up a tall flower stalk; leaves turn bitter	Heat and long days	Harvest right away; replant in cooler weather	Plant early or in fall; heat-tolerant varieties; afternoon shade
Poor Fruit Set	Environment	Tomato, pepper, squash	Flowers drop without forming fruit	Temperatures too hot or cold, or too few pollinators	Wait for milder weather; hand-pollinate squash	Plant flowers nearby for bees; time planting around extreme heat
Sunscald	Environment	Tomato, pepper	Pale, papery patches on the sun-facing side of fruit	Fruit exposed to intense direct sun	Affected fruit is still edible once trimmed	Keep leaf cover healthy; shade cloth in peak summer
Deer and Rabbit Browsing	Wildlife	Hosta, daylily, lettuce, beans, roses	Stems torn (deer) or cleanly clipped (rabbits); plants eaten to the ground	Wildlife feeding	Fencing; repellent sprays reapplied after rain	8 ft fence for deer; 2 ft buried wire for rabbits
Example: Your Problem Here	Pest	Tomato	Describe what the gardener sees	What causes it	How to treat it	How to prevent it