DISEASE: Bacterial wilt
HOST: Alfalfa
Longitudinal section of defined brown gum pockets on inner surface of root bark.

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: S. Thomson
DISEASE: Bacterial wilt
HOST: Alfalfa
Infected plant (left) with typical symptoms of stunting and chlorosis. Other characteristic symptoms are spindly stems and small distorted leaflets. Healthy plant (right).

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: S. Thomson
DISEASE: Bacterial wilt
HOST: Alfalfa
Diseased plant with chlorotic leaves.

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: S. Thomson
DISEASE: Bacterial wilt
HOST: Alfalfa
Cross sections of diseased roots with defined brown gum pockets on inner surface of bark. Healthy root (upper left). Other sections represent increases in disease severity.

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: L. Claflin
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
DISEASE: Elm yellows
HOST: Elm
Symptoms of elm yellows occasionally appear on one branch before others, but more often they involve the entire crown.

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Diseased twig (right) with epinasty, chlorosis, and yellowing of leaves. Sometimes both yellow and green leaves occur on same branch. Healthy branch (left).

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair