DISEASE: Aster yellows
HOST: Marigold
Infected plant (left) with yellowing and stunting.
Aster yellows | Marigold
DISEASE: Aster yellows
HOST: Marigold (Tagetes erecta)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: M. Shurtleff
DISEASE: Aster yellows
HOST: Squash
Diagnostic characteristics for the disease are yellowing of young leaves, proliferation of secondary shoots, and rigid erect habit. Leaves are misshapen and smaller than normal and have stiff, thick laminae.
Aster yellows | Squash
DISEASE: Aster yellows
HOST: Squash (Cucurbita sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: S. Miller
DISEASE: Bacterial leaf streak
HOST: Millet
Leaf with small, linear, water-soaked, reddish brown stripes.
Bacterial leaf streak | Millet
DISEASE: Bacterial leaf streak
HOST: Millet (Pennisetum glaucum)
PATHOGEN: Xanthomonas campestris pv. pennamericanum
SOURCE: L. Claflin
DISEASE: Bacterial leaf streak
HOST: Millet
Advanced stage of disease.
Bacterial leaf streak | Millet
DISEASE: Bacterial leaf streak
HOST: Millet (Pennisetum glaucum)
PATHOGEN: Xanthomonas campestris pv. pennamericanum
SOURCE: L. Claflin
DISEASE: Bacterial leaf stripe
HOST: Millet
Leaf with long reddish stripes, usually vein delimited.
Bacterial leaf stripe | Millet
DISEASE: Bacterial leaf stripe
HOST: Millet (Pennisetum glaucum)
PATHOGEN: Acidovorax avenae
PATHOGEN SYNONYM: Acidovorax avenae subsp. avenae
SOURCE: L. Claflin
DISEASE: Bacterial leaf stripe
HOST: Millet
Leaf with reddish stripes delimited by veins.
Bacterial leaf stripe | Millet
DISEASE: Bacterial leaf stripe
HOST: Millet (Pennisetum glaucum)
PATHOGEN: Acidovorax avenae
PATHOGEN SYNONYM: Acidovorax avenae subsp. avenae
SOURCE: L. Claflin
DISEASE: Bacterial wilt
HOST: Squash
Field with severe symptoms of wilt. Foliage often is chlorotic and leaf margins may be chlorotic and necrotic before plant death. Bacterial ooze may be seen streaming from the xylem when infected stems are cut.
Bacterial wilt | Squash
DISEASE: Bacterial wilt
HOST: Squash (Cucurbita maxima)
PATHOGEN: Erwinia tracheiphila
SOURCE: B. Jacobsen, M. Shurtleff
DISEASE: Pseudomonas leaf spot
HOST: Marigold
Marigolds with yellow apical chlorosis attributed to toxin production by the pathogen.
Pseudomonas leaf spot | Marigold
DISEASE: Pseudomonas leaf spot
HOST: Marigold (Tagetes erecta)
PATHOGEN: Pseudomonas syringae pv. tagetis
SOURCE: R. Durbin
DISEASE: Pseudomonas leaf spot
HOST: Marigold
Chlorotic leaves with total loss of chlorophyll. Disease is also known as toxic chlorosis.
Pseudomonas leaf spot | Marigold
DISEASE: Pseudomonas leaf spot
HOST: Marigold (Tagetes erecta)
PATHOGEN: Pseudomonas syringae pv. tagetis
SOURCE: R. Durbin