Plant disease & disorder profiles
Showing 22 of 74 profiles: symptoms, spread, host crops, and organic-first treatments.
Bean common mosaic virus
Bean common mosaic virus (BCMV)
A seedborne and aphid-transmitted virus that mottles bean leaves and can distort pods, one of the most common bean diseases worldwide.
- Hosts
- Bush bean, Pole bean
Black rot of brassicas
Xanthomonas campestris pv. campestris
A vascular bacterium of cabbage-family crops that enters through leaf edges and water pores, causing distinctive V-shaped yellow wedges that point toward the leaf's blackened veins.
- Hosts
- Cabbage, Broccoli, Cauliflower, Kale
Calcium deficiency
N/A — abiotic (nutrient deficiency/transport disorder)
Calcium barely moves within the plant once deposited, so deficiency symptoms show up specifically in the newest growth and fastest-growing tissue, most famously as blossom end rot on fruit.
- Hosts
- Tomato, Pepper, Cabbage, Lettuce
Clubroot
Plasmodiophora brassicae
A soilborne organism (technically a protist, long grouped with fungal diseases) that infects brassica roots and causes grotesque, swollen, club-shaped galls that cripple water and nutrient uptake.
- Hosts
- Cabbage, Broccoli, Cauliflower, Kale
Crown gall
Agrobacterium tumefaciens
A soil bacterium that inserts a piece of its own DNA into the plant's cells at wound sites, tricking the plant into growing rough, woody tumor-like galls, most often at the crown or graft union.
- Hosts
- Apple, Grape, Raspberry, Blueberry
Cucumber mosaic virus
Cucumber mosaic virus (CMV)
One of the most widespread plant viruses, with an enormous host range spanning vegetables, ornamentals, and weeds. Aphids spread it quickly through a garden even without settling long on any one plant.
- Hosts
- Cucumber, Zucchini, Winter squash, Pepper
Curly top virus
Beet curly top virus (BCTV)
A leafhopper-vectored virus common in hot, dry western regions that causes dramatic upward leaf curling, stunting, and often plant death, especially on tomato and bean.
- Hosts
- Tomato, Pepper, Bush bean
Halo blight
Pseudomonas savastanoi pv. phaseolicola
A bean-specific bacterium that produces small angular spots ringed by a wide, pale-green-to-yellow halo, often larger than the spot itself.
- Hosts
- Bush bean, Pole bean
Lesion nematode
Pratylenchus spp.
A migratory soilborne roundworm that tunnels through roots (rather than settling in one spot like root-knot nematode), leaving dead, discolored lesions that open the door to fungal and bacterial rot organisms.
- Hosts
- Potato, Carrot, Strawberry, Apple
Lettuce mosaic virus
Lettuce mosaic virus (LMV)
A seedborne and aphid-transmitted virus that stunts lettuce and mottles its leaves, a serious quality problem since even light infection makes heads unmarketable.
- Hosts
- Lettuce
Nitrogen deficiency
N/A — abiotic (nutrient deficiency)
Nitrogen is mobile within the plant, so when supply runs short, the plant pulls it from older leaves to support new growth, causing uniform yellowing that starts at the bottom of the plant.
- Hosts
- Corn, Cabbage, Tomato, Lettuce
Overwatering / root suffocation
N/A — abiotic (waterlogging, oxygen deprivation)
Saturated soil pushes air out of the pore spaces roots need to breathe, so roots suffocate and die even though the plant looks like it's drowning in symptoms that mimic drought.
- Hosts
- Tomato, Pepper, Cucumber, Bush bean
Phosphorus deficiency
N/A — abiotic (nutrient deficiency)
Phosphorus deficiency shows up most dramatically as a purple-red pigment building up in older leaves, especially on the undersides and veins, most visible in cool soil that slows phosphorus uptake.
- Hosts
- Corn, Tomato, Pepper
Phytophthora root rot
Phytophthora spp.
A general term for water-mold root rots affecting perennials and fruiting shrubs/trees planted in soil that stays wet, slowly killing the root system from the tips inward.
- Hosts
- Strawberry, Raspberry, Blueberry, Apple
Root-knot nematode
Meloidogyne spp.
A microscopic soilborne roundworm that burrows into roots and triggers swollen galls as the plant's cells are hijacked to feed the nematode. Above-ground symptoms mimic drought or nutrient stress, which makes it easy to misdiagnose without pulling a plant.
- Hosts
- Tomato, Carrot, Cucumber, Pepper
Salt burn
N/A — abiotic (salt toxicity)
Excess soluble salts in the soil, from over-fertilizing, road salt runoff, or naturally saline soil/water, pull moisture out of roots and scorch leaf margins.
- Hosts
- Lettuce, Bush bean, Carrot, Strawberry
Soil compaction stress
N/A — abiotic (physical root restriction)
Repeated foot traffic, tilling wet soil, or heavy equipment presses soil particles together, squeezing out the pore space roots need to grow and water needs to drain through.
- Hosts
- Carrot, Potato, Tomato, Bush bean
Squash mosaic virus
Squash mosaic virus (SqMV)
A seedborne and beetle-transmitted virus of cucurbits producing sharp mosaic mottling and often severe fruit distortion, more disfiguring on fruit than cucumber mosaic virus.
- Hosts
- Zucchini, Winter squash, Pumpkin, Cucumber
Sulfur deficiency
N/A — abiotic (nutrient deficiency)
Sulfur deficiency looks a lot like nitrogen deficiency, an overall pale yellowing, but unlike nitrogen it shows up on the youngest leaves first since sulfur is less mobile within the plant.
- Hosts
- Cabbage, Broccoli, Onion, Corn
Tobacco/tomato mosaic virus
Tobacco mosaic virus (TMV) / Tomato mosaic virus (ToMV)
A remarkably stable virus that mottles leaves in patches of light and dark green and stunts growth. It survives for years in dried plant debris and even in tobacco products, which is one of its unusual routes into a garden.
- Hosts
- Tomato, Pepper
Tomato spotted wilt virus
Tomato spotted wilt virus (TSWV)
A thrips-vectored virus with a very wide host range, causing bronzing, ring spots, and stunted, one-sided growth. Once thrips introduce it, there's no cure.
- Hosts
- Tomato, Pepper, Lettuce
Verticillium wilt
Verticillium dahliae
A cool-weather cousin of Fusarium wilt with an enormous host range (over 200 plant species), clogging the vascular system and producing distinctive V-shaped yellow wedges on leaves.
- Hosts
- Tomato, Potato, Eggplant, Pepper
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