DISEASE: Brittle root
HOST: Horseradish
Dying, stunted, yellow to brown horseradish plants.

Brittle root | Horseradish
DISEASE: Brittle root
HOST: Horseradish (Armoracia rusticana)
PATHOGEN: Spiroplasma citri
SOURCE: C. Eastman, M. Davis
DISEASE: Brittle root
HOST: Horseradish
Close-up of stunted, yellow horseradish plants.

Brittle root | Horseradish
DISEASE: Brittle root
HOST: Horseradish (Armoracia rusticana)
PATHOGEN: Spiroplasma citri
SOURCE: D. Sherrod
DISEASE: Brittle root
HOST: Horseradish
Horseradish with discolored internal tissues. Healthy root segment (top right).

Brittle root | Horseradish
DISEASE: Brittle root
HOST: Horseradish (Armoracia rusticana)
PATHOGEN: Spiroplasma citri
SOURCE: J. Fletcher, M. Davis
DISEASE: Brown line and decline
HOST: Almond
Stunted and yellowish diseased tree. Such trees produce little to no growth and decline rapidly.

Brown line and decline | Almond
DISEASE: Brown line and decline
HOST: Almond (Prunus dulcis)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: B. Teviotdale
DISEASE: Brown line and decline
HOST: Almond
Bark was split laterally at graft union, revealing line of necrotic tissue that extends into woody cortical tissues.

Brown line and decline | Almond
DISEASE: Brown line and decline
HOST: Almond (Prunus dulcis)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: J. Uyemoto
DISEASE: Brown line and decline
HOST: Almond
Shriveled nuts from infected tree. Two healthy kernels (bottom left).

Brown line and decline | Almond
DISEASE: Brown line and decline
HOST: Almond (Prunus dulcis)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: J. Uyemoto
DISEASE: Common scab (Potato scab)
HOST: Potato
Symptoms of common scab vary depending upon the cultivar. The lesions can be shallow or deep, erumpent and corky, and vary in color.

Common scab (Potato scab) | Potato
DISEASE: Common scab (Potato scab)
HOST: Potato (Solanum tuberosum)
PATHOGEN: Streptomyces scabiei
PATHOGEN SYNONYM: Streptomyces scabies
SOURCE: A. Secor
DISEASE: Common scab (Potato scab)
HOST: Potato
White-skinned tuber with sunken and superficial scab lesions.

Common scab (Potato scab) | Potato
DISEASE: Common scab (Potato scab)
HOST: Potato (Solanum tuberosum)
PATHOGEN: Streptomyces scabiei
PATHOGEN SYNONYM: Streptomyces scabies
SOURCE: S. Thomson
DISEASE: Common scab (Potato scab)
HOST: Potato
Red-skinned tuber with lesions that usually penetrate less than 1 mm.

Common scab (Potato scab) | Potato
DISEASE: Common scab (Potato scab)
HOST: Potato (Solanum tuberosum)
PATHOGEN: Streptomyces scabiei
PATHOGEN SYNONYM: Streptomyces scabies
SOURCE: S. Thomson