Potatoes:Key
KEY TO POTATO PESTS AND NUTRITIONAL DISORDERS
Contents
- 1 Seed
- 2 Seedling
- 3 Root
- 3.1 BLACK
- 3.2 BLUE
- 3.3 BROWN
- 3.3.1 Black dot
- 3.3.2 Brown rot; Ring rot
- 3.3.3 Common scab; Skin spot; Black dot
- 3.3.4 Cyst nematode
- 3.3.5 Fusarium wilts; Verticillium wilt
- 3.3.6 Lesion nematodes
- 3.3.7 Pink rot
- 3.3.8 Pink rot
- 3.3.9 Powdery scab
- 3.3.10 Powdery scab; Root-knot nematode
- 3.3.11 Powdery scab; Skin spot
- 3.3.12 Powdery scab; Smut
- 3.3.13 Rhizoctonia
- 3.3.14 Skin spot
- 3.3.15 Skin spot
- 3.3.16 Stem-end browning
- 3.3.17 Wart
- 3.4 DARK
- 3.5 GRAY
- 3.6 GREEN
- 3.7 LIGHT
- 3.8 PURPLE
- 3.9 RED
- 3.10 SILVER
- 3.11 WHITE
- 3.12 YELLOW
- 3.13 No Distinct Discoloration
- 3.13.1 Black dot
- 3.13.2 Black dot; Violet root rot; Brown rot; Charcoal rot
- 3.13.3 Chemical injury; Jelly end rot; Stem-end browning; Brown rot; Ring rot; Stem rot; Verticillium wilt; Fusarium wilts; Boron deficiency; Charcoal rot; Pink rot
- 3.13.4 Cyst nematode; Root-knot nematode
- 3.13.5 False root-knot nematode
- 3.13.6 Fusarium wilts
- 3.13.7 Fusarium wilts; Mycoplasmas
- 3.13.8 Genetic abnormalities
- 3.13.9 Lesion nematode
- 3.13.10 Lesion nematode
- 3.13.11 Nematodes
- 3.13.12 Phosphorus deficiency
- 3.13.13 Pink rot
- 3.13.14 Potassium deficiency; Boron deficiency; Aluminum toxicity; Cyst nematode; Stubby-root nematode
- 3.13.15 Rhizoctonia
- 3.13.16 Rhizoctonia; Blackleg; Mycoplasmas
- 3.13.17 Ring rot leak
- 3.13.18 Root-knot nematode
- 3.13.19 Rot nematode
- 3.13.20 Rot nematode
- 3.13.21 Smut
- 3.13.22 Soft rot; Blackleg
- 3.13.23 Stem-end browning; Chemical injury; Low temperature injury; Calcium deficiency; Fusarium wilt; Verticillium wilt
- 3.13.24 TRV; PMTV
- 3.13.25 Verticillium wilt; Chemical injury; Stem-end browning
- 3.13.26 Wart
- 4 Stem=
- 4.1 BLACK
- 4.2 BROWN
- 4.3 GRAY
- 4.4 GREEN
- 4.5 TAN
- 4.6 WHITE
- 4.7 YELLOW
- 4.8 No Distinct Discoloration
- 4.8.1 Blackleg; Rhizoctonia; Mycoplasma; Fusarium wilts; BCTV; Psyllid yellows
- 4.8.2 Coiled sprout
- 4.8.3 Enlarged lenticels; Bacterial soft rot; Powdery Scab; Stem rot; Charcoal rot; Gangrene; PSTV
- 4.8.4 Fusarium wilts
- 4.8.5 Genetic abnormalities; Hair sprout; Mycoplasmas; TMV
- 4.8.6 Genetic abnormalities; Mycoplasmas
- 4.8.7 Giant hill
- 4.8.8 Manganese toxicity
- 4.8.9 Mycoplasmas
- 4.8.10 PAMV; PVM; TMV; CMV; TBRV; TRV; PMTV; APMV; PSTV; Genetic abnormalities; Chemical injury
- 4.8.11 PVY
- 4.8.12 PVY; PMTV; PYDV
- 4.8.13 Rusts; Coiled sprout
- 4.8.14 TRV
- 4.8.15 Wart; Smut
- 5 Leaf
- 5.1 BLACK
- 5.2 BRIGHT
- 5.3 BRONZE
- 5.4 BROWN
- 5.5 GREEN
- 5.6 LIGHT
- 5.7 ORANGE
- 5.8 PALE
- 5.9 PINK
- 5.10 PURPLE
- 5.11 RED
- 5.12 TAN
- 5.13 WHITE
- 5.14 YELLOW
- 5.14.1 Black dot; Violet root rot; Brown rot; Charcoal rot
- 5.14.2 AMV; TRV; PMTV; TBRV; PYVV; TRSV
- 5.14.3 Blackleg; Rhizoctonia; Mycoplasma; Fusarium wilts; BCTV; Psyllid yellows
- 5.14.4 Blackleg; Rhizoctonia; Mycoplasmas; Fusarium wilts
- 5.14.5 Brown rot; Fusarium wilt; Verticillium wilt; Ring rot
- 5.14.6 Calcium deficiency
- 5.14.7 Cercospora leaf blotch
- 5.14.8 Fusarium wilt; Verticillium wilt
- 5.14.9 Lightning injury
- 5.14.10 Magnesium deficiency
- 5.14.11 Nonvirus leafroll; PLRV; PVM; Potassium; Phosphorus; or Boron deficiency
- 5.14.12 PAMV
- 5.14.13 Phosphorus deficiency
- 5.14.14 PLRV in andigena types
- 5.14.15 PVS
- 5.14.16 Ring rot
- 5.14.17 Ring rot; Brown rot; Pink rot; Stem rot
- 5.14.18 Rosellinia
- 5.14.19 Sulfur dioxide air pollution; Manganese toxicity; Magnesium deficiency
- 5.14.20 Zinc deficiency
- 5.15 No Distinct Discoloration
- 5.15.1 AMV; APMV; TSWV
- 5.15.2 APLV
- 5.15.3 APLV
- 5.15.4 Boron deficiency; PYDV; Fusarium wilts
- 5.15.5 Chemical injury
- 5.15.6 Chemical injury; CMV; TMV; Low temperature nitrogen toxicity
- 5.15.7 Choanephora blight
- 5.15.8 Early blight; Photochemical oxidant air pollution; Powdery mildew; Pink rot; PVY
- 5.15.9 Frost injury
- 5.15.10 Fusarium wilts
- 5.15.11 Genetic abnormalities; Witches'-broom; Stolbur
- 5.15.12 Giant hill
- 5.15.13 Low temperature vine injury
- 5.15.14 Manganese toxicity
- 5.15.15 Mycoplasmas
- 5.15.16 Nitrogen deficiency; Chemical injury; Photochemical oxidant air pollution; Manganese toxicity
- 5.15.17 PAMV; PVM; TMV; CMV; TBRV; TRV; PMTV; APMV; PSTV; Genetic abnormalities; Chemical injury
- 5.15.18 Phosphorus deficiency
- 5.15.19 PSTV
- 5.15.20 PVT
- 5.15.21 PVX; PVS; PVM; PVY; PVA; PVT; APMV; APLV; CMV; TMV; TRV; AMV; PAMV; Deforming mosaic; Frost injury
- 5.15.22 PVY
- 5.15.23 PVY; PVA; Deforming mosaic
- 5.15.24 PVY; PVM; PYVV
- 5.15.25 PYDV
- 5.15.26 Ring rot
- 5.15.27 Septoria leaf spot
- 5.15.28 TBRV
- 5.15.29 TBRV; TRSV; TSWV; PVY
- 5.15.30 TSWV; PVY
- 5.15.31 Wind injury
- 5.15.32 Wind or hail injury; Ulocladium blight
- 5.15.33 Zinc deficiency
- 6 Tuber
- 6.1 BLACK
- 6.2 BROWN
- 6.3 CREAM
- 6.4 DARK
- 6.5 GRAY
- 6.6 GREEN
- 6.7 LIGHT
- 6.8 PINK
- 6.9 PURPLE
- 6.10 RED
- 6.11 RUST
- 6.12 SILVER
- 6.13 TAN
- 6.14 WHITE
- 6.15 YELLOW
- 6.16 No Distinct Discoloration
- 6.16.1 AMV; PYDV; TRV; TSWV; PSTV; Chemical injury
- 6.16.2 Bacterial soft rot; Powdery scab; Leak; Fusarium tuber rots; Gangrene
- 6.16.3 Blackleg
- 6.16.4 Calcium deficiency
- 6.16.5 Calcium deficiency; Stem-end browning; Fusarium wilts
- 6.16.6 Chemical injury
- 6.16.7 Coiled sprout
- 6.16.8 Frozen tubers
- 6.16.9 Frozen tubers
- 6.16.10 Fusarium tuber rot
- 6.16.11 Fusarium wilt; Fusarium tuber rot
- 6.16.12 Gangrene
- 6.16.13 Gangrene
- 6.16.14 Genetic abnormalities; Hair sprout; Mycoplasma
- 6.16.15 Hollow heart
- 6.16.16 Internal sprouting
- 6.16.17 Jelly end rot
- 6.16.18 Lightning injury
- 6.16.19 Low storage temperature
- 6.16.20 Low temperature injury
- 6.16.21 Mycoplasma
- 6.16.22 PLRV; Low temperature injury; Stem-end browning; PAMV
- 6.16.23 PMTV
- 6.16.24 Potassium deficiency
- 6.16.25 PSTV
- 6.16.26 Psyllid yellows; Witches'-broom; Second growth
- 6.16.27 Rhizoctonia
- 6.16.28 Rhizoctonia; Blackleg; Mycoplasmas
- 6.16.29 Ring rot
- 6.16.30 Ring rot; Brown rot
- 6.16.31 Second growth
- 6.16.32 Second growth; Compacted soil; PAMV; PSTV; Rhizoctonia; Mycoplasmas
- 6.16.33 Second growth; Frozen tissue
- 6.16.34 Second growth; Immature tubers
- 6.16.35 Second growth; PSTV
- 6.16.36 Second growth; PYVV
- 6.16.37 Second growth; Secondary tubers
- 6.16.38 Second growth; Secondary tubers; Calcium deficiency; Hair sprouts
- 6.16.39 Stem rot
- 6.16.40 Sunscald
- 6.16.41 Surface abrasions
- 6.16.42 Thecaphora smut
- 6.16.43 TNV
- 6.16.44 TRV; PMTV
- 6.16.45 TRV; PMTV
- 6.16.46 TRV; PMTV; TSWV; PAMV
- 6.16.47 Tuber cracks; Rhizoctonia; PYDV; PSTV; PMTV; TNV; Boron deficiency
- 6.16.48 Verticillium wilt; Chemical injury; Stem-end browning
- 6.16.49 Viruses; Genetic abnormalities; Nutrient imbalances
- 6.16.50 White mold; Fusarium tuber rot
- 6.16.51 Wind injury
- 6.16.52 Witches'-broom
- 6.16.53 Witches'-broom; Psyllid yellows; Second growth
- 6.16.54 Cyst nematode
- 7 Whole Plant
Seed
Seed disorders are limited to disorders while in the ground and not to potential disorders inherent in the seed.
No Distinct Discoloration
PYDV; APMV; Mycoplasmas
Dormant seed tubers or late germination
BLACK
Blackleg; Pink rot
Black underground lesions extending upward from seed tuber, dark pith and cortical decay
BROWN
Skin spot with girdling
Brown lesions and transverse cracks while the seeds are in storage
No Distinct Discoloration
Blackleg
Soft tuber, necrosis progressing from the seed piece
No Distinct Discoloration
Oxygen relations; Blackheart; Adverse temperature; Fusarium tuber rots; Leak; Bacterial soft rot; Stem rot
Decay of seed tubers
Seedling
No Distinct Discoloration
AMV; APMV; TSWV
Systemic leaflet and petiole necrosis
Root
BLACK
Black dot
Silvery to brown shallow lesions with very small black sclerotia
Blackleg; Pink rot
Black underground lesions extending upward from seed tuber, dark pith and cortical decay
Blackspot
Subsurface tissue is blue to black
Brown rot; Ring rot
Rotting vascular tissue is discolored reddish brown to black
Pink rot
Tissue under lenticels is brown to black
Pink rot
Brown to black necrosis on roots
Rosellinia
Loose gray white mycelium on surface and in soil; rot black; carbonaceous
Violet root rot
Purplish black sclerotia
Wart
Galls that are green or brown to black
BLUE
Blackspot
Subsurface tissue is blue to black
BROWN
Black dot
Brown lesions with dotlike sclerotia on stolons
Brown rot; Ring rot
Rotting vascular tissue is discolored reddish brown to black
Common scab; Skin spot; Black dot
Brown underground lesions
Cyst nematode
White to brown cysts on roots
Fusarium wilts; Verticillium wilt
Brown vascular discoloration, most severe in lower part, extending also above ground
Lesion nematodes
Irregular purplish brown shallow lesions
Pink rot
Brown to black necrosis on roots
Pink rot
Tissue under lenticels is brown to black
Powdery scab
White tufts on brown galls that later become a necrotic depression
Powdery scab; Root-knot nematode
White to dark brown galls on roots
Powdery scab; Skin spot
Raised, pimplelike, purple-brown galls
Powdery scab; Smut
White to brown galls on stolons
Rhizoctonia
Brown lesions on stolons and girdling
Skin spot
Brown lesions on stolons
Skin spot
Brown lesions on roots
Stem-end browning
Subsurface tissue is brown at stolen attachment
Wart
Galls that are green or brown to black
DARK
Rosellinia
Dark stolons, covered by a gray-white mycelium
GRAY
Brown rot
Abundant, gray bacterial exudate from vascular tissue
Rosellinia
Dark roots, covered by gray-white mycelium; necrosis
Rosellinia
Underground lesions with prominent gray fungus, mold growth
GREEN
Wart
Galls that are green or brown to black
LIGHT
Pleospora herbarum
Light colored necrotic lesions
PURPLE
Lesion nematodes
Irregular purplish brown shallow lesions
Powdery scab; Skin spot
Raised, pimplelike, purple-brown galls
Violet root rot
Purplish black sclerotia
RED
Brown rot; Ring rot
Rotting vascular tissue is discolored reddish brown to black
SILVER
Black dot
Silvery to brown shallow lesions with very small black sclerotia
WHITE
Cyst nematode
White to brown cysts on roots
Enlarged lenticels
White tufts on galls
Powdery scab
White tufts on brown galls that later become a necrotic depression
Powdery scab; Root-knot nematode
White to dark brown galls on roots
Powdery scab; Smut
White to brown galls on stolons
Ring rot
Sparse, white bacterial exudate from vascular tissue
Rosellinia
Loose gray white mycelium on surface and in soil; rot black; carbonaceous
Rosellinia
Grayish white mycelium in or on soil
YELLOW
Verticillium wilt; Fusarium wilts
Chlorosis, wilt, and early death with vascular discoloration
No Distinct Discoloration
Black dot
Dotlike sclerotia and decay on roots
Black dot; Violet root rot; Brown rot; Charcoal rot
Chlorosis, wilt, and early death
Chemical injury; Jelly end rot; Stem-end browning; Brown rot; Ring rot; Stem rot; Verticillium wilt; Fusarium wilts; Boron deficiency; Charcoal rot; Pink rot
Stolon attachment discolored
Cyst nematode; Root-knot nematode
Proliferation of lateral roots
False root-knot nematode
Galls as beads along root
Fusarium wilts
General rot of roots
Fusarium wilts; Mycoplasmas
Rotted underground lesions with dry shredding
Genetic abnormalities
Numerous, long stolons
Lesion nematode
Cortical injury on roots
Lesion nematode
Warty galls with pimples
Nematodes
Wilt with drought stress
Phosphorus deficiency
Short stolons
Pink rot
Stolons with necrosis
Potassium deficiency; Boron deficiency; Aluminum toxicity; Cyst nematode; Stubby-root nematode
Poor development of roots
Rhizoctonia
Large sclerotia and decay on roots
Rhizoctonia; Blackleg; Mycoplasmas
Tubers set close to stem, stolons are very short
Ring rot leak
Cortex less severely rotted than medulla
Root-knot nematode
Warty galls
Rot nematode
Chalky white spots below skin becoming dark, dry and granular
Rot nematode
Rotting tissue is dry and shrinking
Smut
Tuberlike, deformed galls
Soft rot; Blackleg
Stolon attachment and medullary areas are discolored
Stem-end browning; Chemical injury; Low temperature injury; Calcium deficiency; Fusarium wilt; Verticillium wilt
Firm interior at stolon attachment
TRV; PMTV
Subsurface tissue has necrotic arcs to flecks
Verticillium wilt; Chemical injury; Stem-end browning
Netlike tuber that becomes more severe near the stolon end
Wart
Galls on tips of stolons
Stem=
BLACK
Blackleg
Black pith necrosis at the stem base
Brown rot; Blackleg
Black vascular discoloration
Powdery mildew
Necrotic lesions that are green to black with a white to gray-brown sporulation; brown to black stippled flecks on stem lesions
White mold
Black sclerotia; moldy surface; white at soil line; watery rot; stem collapse
BROWN
Fusarium wilts; Verticillium wilt
Brown vascular discoloration, most severe in lower part, extending also above ground
Powdery mildew
Necrotic lesions that are green to black with a white to gray-brown sporulation; brown to black stippled flecks on stem lesions
Powdery mildew
Necrotic lesions that are green to black with a white to gray-brown sporulation; brown to black stippled flecks on stem lesions
PVY; PMTV; TRV
Brown rings to necrotic areas on surface
PVY; TSWV
Brown necrotic streaks on stems and petioles
PYDV
Brown pith necrosis near tip
Rhizoctonia
Brown underground lesions girdling the stem
White mold
Brown necrotic streaks on stems and petioles; light brown broad zonation
GRAY
Powdery mildew
Necrotic lesions that are green to black with a white to gray-brown sporulation; brown to black stippled flecks on stem lesions
GREEN
Powdery mildew
Necrotic lesions that are green to black with a white to gray-brown sporulation; brown to black stippled flecks on stem lesions
TAN
Stem rot
Tan sclerotia; moldy surface; white at soil line; watery rot; stem collapse
Stemphylium consortiale
Tan, angular necrotic lesions
WHITE
Lightning injury
White epidermis at soil line, cross-hatched collapse of pith
Powdery mildew
Necrotic lesions that are green to black with a white to gray-brown sporulation; brown to black stippled flecks on stem lesions
Rhizoctonia solani
White mycelium accompanying lesions at or near the soil surface
Stem rot
Tan sclerotia; moldy surface; white at soil line; watery rot; stem collapse
YELLOW
Brown rot; Fusarium wilt; Verticillium wilt; Ring rot
Wilt or chlorosis on one stem or on one side of leaf, stem, or side of plant
Lightning injury
Wilt or chlorosis and rapid green collapse and death of some or all plants in a localized area of the field
Ring rot; Brown rot; Pink rot; Stem rot
Wilt or chlorosis of green leaves and stems, later necrosis
Verticillium wilt; Fusarium wilts
Chlorosis, wilt, and early death with vascular discoloration
No Distinct Discoloration
Blackleg; Rhizoctonia; Mycoplasma; Fusarium wilts; BCTV; Psyllid yellows
Red pigmentation or chlorosis of apical leaves, stunting, general chlorosis, thickening of nodes, aerial tubers, vascular necrosis, basal stem necrosis, or early death
Coiled sprout
Numerous stems
Enlarged lenticels; Bacterial soft rot; Powdery Scab; Stem rot; Charcoal rot; Gangrene; PSTV
Lenticels affected
Fusarium wilts
Pith necrosis at nodes
Genetic abnormalities; Hair sprout; Mycoplasmas; TMV
Numerous, thin stems
Genetic abnormalities; Mycoplasmas
Numerous stems, bushy
Giant hill
Unusually large plant
Manganese toxicity
Necrosis of veins and appears as flecks to streaks; brown to black stippled flecks on petiole; stem brittle
Mycoplasmas
Small leaves with numerous thin stems
PAMV; PVM; TMV; CMV; TBRV; TRV; PMTV; APMV; PSTV; Genetic abnormalities; Chemical injury
Small twisted leaves possibly with short petioles and stem internodes
PVY
Necrosis of veins and stem streak
PVY; PMTV; PYDV
Stunting of some stems and internodes shortened
Rusts; Coiled sprout
Swelling, twisting and deformation on stem
TRV
Stunting of some stems
Wart; Smut
Galls on stem
Leaf
BLACK
Early blight
Firm black lesions, slightly sunken, relatively shallow
Manganese toxicity
Brown to black stippled flecks on petiole; stem brittle
TSWV
Brown black necrotic lesions with concentric zonation
BRIGHT
AMV; TRV; PMTV; TBRV; PYVV; TRSV
Mosaic mottles in yellow areas, pale to bright
BRONZE
Fusarium wilt
Bronzed leaves and extensive systemic necrosis
Photochemical oxidant air pollution
Bronzed on the upper leaf surface and margins
Photochemical oxidant air pollution; Potassium or Zinc deficiency; Fusarium wilt
General bronzing or of old leaves
Potassium deficiency
Bronzed, necrotic leaves; downward leaf curl; underlying tissue firm, corky at stolon end
Psyllid yellows
Bronzing of leaf tips
PVS
Bronzed leaves with necrotic spots
BROWN
Blackleg; Late blight; Gray mold
Brown necrotic streaks at petiole attachment
Early blight
Brown to black lesions, restricted in size
Manganese toxicity
Brown to black stippled flecks on petiole; stem brittle
Phoma leaf spot
Round, brown necrotic lesions with narrow zonation
PVY; TSWV
Brown necrotic streaks on stems and petioles
Rusts
Leaves containing pustules that are orange or red to brown enlargements; twisting
TSWV
Brown black necrotic lesions with concentric zonation
GREEN
PVS
Chlorotic greenish spots on low shaded leaves
LIGHT
Pleospora herbarum
Light colored necrotic lesions
ORANGE
Rusts
Leaves containing pustules that are orange or red to brown enlargements; twisting
PALE
AMV; TRV; PMTV; TBRV; PYVV; TRSV
Mosaic mottles in yellow areas, pale to bright
PLRV; Boron deficiency
Leaves that are stiff, upward rolling, papery in texture, and pale color
PINK
PLRV; Manganese deficiency; PVM; Mycoplasmas; BCTV; Psyllid yellows
Upward rolling of leaf tips, possibly pink at margins
PURPLE
Cercospora leaf blotch
Yellowish to purple necrotic lesions
RED
Blackleg; Rhizoctonia; Mycoplasma; Fusarium wilts; BCTV; Psyllid yellows
Red pigmentation or chlorosis of apical leaves, stunting, general chlorosis, thickening of nodes, aerial tubers, vascular necrosis, basal stem necrosis, or early death
Blackleg; Rhizoctonia; Mycoplasmas; Fusarium wilts
Upward rolling severe at plant tip, chlorosis or red at bases of tip leaves, may be accompanied by aerial tubers
Rusts
Leaves containing pustules that are orange or red to brown enlargements; twisting
TAN
Stemphylium consortiale
Tan, angular necrotic lesions
WHITE
Sulfur dioxide air pollution; Manganese toxicity; Magnesium deficiency
Interveinal white-yellow chlorosis
Sunscald; Hail injury
Lesions above soil surface; epidermis white, underlying tissue usually unaffected
YELLOW
Black dot; Violet root rot; Brown rot; Charcoal rot
Chlorosis, wilt, and early death
AMV; TRV; PMTV; TBRV; PYVV; TRSV
Mosaic mottles in yellow areas, pale to bright
Blackleg; Rhizoctonia; Mycoplasma; Fusarium wilts; BCTV; Psyllid yellows
Red pigmentation or chlorosis of apical leaves, stunting, general chlorosis, thickening of nodes, aerial tubers, vascular necrosis, basal stem necrosis, or early death
Blackleg; Rhizoctonia; Mycoplasmas; Fusarium wilts
Upward rolling severe at plant tip, chlorosis or red at bases of tip leaves, may be accompanied by aerial tubers
Brown rot; Fusarium wilt; Verticillium wilt; Ring rot
Wilt or chlorosis on one stem or on one side of leaf, stem, or side of plant
Calcium deficiency
Upward rolling of lower leaves or throughout the plant with chlorotic or necrotic margins
Cercospora leaf blotch
Yellowish to purple necrotic lesions
Fusarium wilt; Verticillium wilt
General chlorosis of leaves
Lightning injury
Wilt or chlorosis and rapid green collapse and death of some or all plants in a localized area of the field
Magnesium deficiency
Upward rolling of leaves; thick, brittle, interveinal chlorosis or necrosis
Nonvirus leafroll; PLRV; PVM; Potassium; Phosphorus; or Boron deficiency
Upward rolling of lower leaves or throughout the plant, chlorosis absent to mild
PAMV
Mosaic mottles in yellow areas, more severe on lower leaves
Phosphorus deficiency
Spindly, crinkled leaves with chlorotic to necrotic margins
PLRV in andigena types
Upward rolling of leaves; dwarfing; marginal and interveinal chlorosis
PVS
Chlorotic greenish spots on low shaded leaves
Ring rot
Interveinal chlorosis or necrosis of lower leaves
Ring rot; Brown rot; Pink rot; Stem rot
Wilt or chlorosis of green leaves and stems, later necrosis
Rosellinia
Chlorosis, wilt, and early death in groups in the field
Sulfur dioxide air pollution; Manganese toxicity; Magnesium deficiency
Interveinal white-yellow chlorosis
Zinc deficiency
Upward rolling of leaves with chlorosis
No Distinct Discoloration
AMV; APMV; TSWV
Systemic leaflet and petiole necrosis
APLV
Netting of minor leaf veins
APLV
Netting of minor leaf veins
Boron deficiency; PYDV; Fusarium wilts
Bushy appearance
Chemical injury
Spindly, crinkled leaves
Chemical injury; CMV; TMV; Low temperature nitrogen toxicity
Leaves elongated, puckered, pinched with prominent veins
Choanephora blight
Water-soaked large necrotic lesions
Early blight; Photochemical oxidant air pollution; Powdery mildew; Pink rot; PVY
Defoliation from bottom toward top of plant
Frost injury
Necrosis at the tips of the plant
Fusarium wilts
Mosaic mottles on leaf tips
Genetic abnormalities; Witches'-broom; Stolbur
Many leaves that are simple (not compound)
Giant hill
Unusually large plant
Low temperature vine injury
Irregular holes on leaves; banded; mottled
Manganese toxicity
Necrosis of veins and appears as flecks to streaks
Mycoplasmas
Small leaves with numerous thin stems
Nitrogen deficiency; Chemical injury; Photochemical oxidant air pollution; Manganese toxicity
Necrotic lesions speckling lower and upper leaves
PAMV; PVM; TMV; CMV; TBRV; TRV; PMTV; APMV; PSTV; Genetic abnormalities; Chemical injury
Small twisted leaves possibly with short petioles and stem internodes
Phosphorus deficiency
Cupped leaves
PSTV
Small leaves with fluted margins, acute petiole-stem angle
PVT
Netting of minor leaf veins and veinal necrosis
PVX; PVS; PVM; PVY; PVA; PVT; APMV; APLV; CMV; TMV; TRV; AMV; PAMV; Deforming mosaic; Frost injury
Mosaic mottles very mild to severe rugosity
PVY
Systemic leaflet and petiole necrosis and leaf drop
PVY; PVA; Deforming mosaic
Crinkled, rugose leaves
PVY; PVM; PYVV
Mosaic mottles causing rough, crinkly leaves
PYDV
Upward rolling leaves throughout the plant and downward rolling of petioles
Ring rot
Rosette with dwarfing
Septoria leaf spot
Round or angular necrotic lesions with pycnidia
TBRV
Cupped leaf tips
TBRV; TRSV; TSWV; PVY
Necrotic spots and rings
TSWV; PVY
Necrosis of petioles and leaflets
Wind injury
Necrosis on epidermal surface or extending through the leaf
Wind or hail injury; Ulocladium blight
Upward rolling of leaves with tattered edges or holes
Zinc deficiency
Young leaves cupped and twisted
Tuber
BLACK
Blackheart
Interior firm to soft with a black medulla
Charcoal rot
Semiwatery rot; light gray cavities with mycelium and black sclerotia
Common scab; TNV
Tan brown to black tubers
Early blight
Firm black lesions, slightly sunken, relatively shallow
Frost injury
Watery rot on exposure to air, turning shades of pink, brown and black
Fusarium wilts
Brown to black discoloration in a firm tuber, possibly with a water-soaked border
Late blight
Necrotic lesions that are black when wet, brown when dry, with or without sparse white sporulation, possibly yellow halo
Rhizoctonia
Black sclerotia on tuber surface
Skin spot
Eyes with purplish black raised spots
Smut
Tubers that are warty with internal black, scattered areas
Ulocladium blight
Necrotic lesions dark to black at mechanical wounds
White mold
Shrunken tuber; cavities spongy with white mycelium and black sclerotia
White mold; Gray mold; Rhizoctonia; Charcoal rot
Black sclerotia
BROWN
Brown rot; Pink rot; Pink eye
Gray-brown discoloration through skin
Common scab; TNV
Tan brown to black tubers
Early blight
Brown to black lesions, restricted in size
Frost injury
Watery rot on exposure to air, turning shades of pink, brown and black
Fusarium wilts
Brown to black discoloration in a firm tuber, possibly with a water-soaked border
Gray mold
Semiwatery rot with brown flabby decay
Late blight
Firm reddish brown lesions, slightly sunken, relatively shallow
Low temperature injury
Firm interior with mahogany colored interior
PAMV
Brown sunken blotches on tuber
Powdery scab
Raised pustules on tubers are white, later depressed and dark brown
Rhizoctonia
Brown lesions on tubers in the field
Rhizopus
Watery dark rot, drying later as chocolate brown zonate lesions
Silver scurf
Shallow lesions with a silvery sheen to light brownish surface
Xylaria; Armillaria
Brown mycelium in strands near or on tubers
CREAM
Bacterial soft rot; Fusarium tuber rots
Slimy rot that is cream to tan, often with a foul odor
DARK
Brown rot
Dark colored eyes with adhering soil
Gangrene; Sunscald; High temperature field injury; Low temperature injury; Wind injury; TNV
Shallow lesions with dark necrotic skin
Leak; Pink rot
Watery dark rot, later spongy
Rot nematode
Chalky white spots below skin becoming dark, dry and granular
Ulocladium blight
Necrotic lesions dark to black at mechanical wounds
GRAY
Blackheart
Gray smoky cortex with black medulla
Brown rot; Pink rot; Pink eye
Gray-brown discoloration through skin
Charcoal rot
Semiwatery rot; light gray cavities with mycelium and black sclerotia
Leak
Rotting while the tuber shell remains intact; gray smoky discoloration anywhere bordering rotted tissue
Low temperature injury
Gray smoky cortex, vascular ring, or medulla
GREEN
Tuber greening
Shades of green on the surface and/or interior
LIGHT
Heat injury
Lesions girdling and causing collapse; bleached color
PINK
Frost injury
Watery rot on exposure to air, turning shades of pink, brown and black
Pink eye; Verticillium wilt
Discolored eyes at tuber tip
PURPLE
Skin spot
Raised lesions that are purplish corky and may develop into necrotic spots, sometimes around eyes
Violet root rot
Firm lesions, slightly sunken, relatively shallow; purplish mycelial mat
RED
Late blight
Firm reddish brown lesions, slightly sunken, relatively shallow
Violet root rot
Reddish purple mycelium and sclerotia on surface of tuber with sunken areas below
RUST
Internal heat necrosis; Calcium deficiency; AMV; PAMV; PYDV; TRV
Firm interior with necrotic rust colored spots or flecks mostly in medullary tissue
SILVER
Silver scurf
Shallow lesions with a silvery sheen to light brownish surface
TAN
Bacterial soft rot; Fusarium tuber rots
Slimy rot that is cream to tan, often with a foul odor
Common scab; TNV
Tan brown to black tubers
Gray mold
Necrotic lesions with broad zonation, wedge-shaped, circular to irregular, tan sporulation
PVY
Firm interior with necrotic to tan discolored areas
Stemphylium consortiale
Tan, angular necrotic lesions
WHITE
Late blight
Necrotic lesions that are black when wet, brown when dry, with or without sparse white sporulation, possibly yellow halo
Powdery scab
Raised pustules on tubers are white, later depressed and dark brown
Rot nematode
Chalky white spots below skin becoming dark, dry and granular
Stem rot
Fanlike mycelium on tuber and on soil surface; semifirm decay; cheesy rot; tan sclerotia; moldy surface; white at soil line; watery rot; stem collapse
White mold
Shrunken tuber; cavities spongy with white mycelium and black sclerotia
YELLOW
Late blight
Necrotic lesions that are black when wet, brown when dry, with or without sparse white sporulation, possibly yellow halo
No Distinct Discoloration
AMV; PYDV; TRV; TSWV; PSTV; Chemical injury
Tubers that are dwarfed, deformed, possibly cracked, with internal necrotic spots
Bacterial soft rot; Powdery scab; Leak; Fusarium tuber rots; Gangrene
Infected wounds
Blackleg
Soft tuber, necrosis progressing from the seed piece
Calcium deficiency
Necrotic just below the tuber tip
Calcium deficiency; Stem-end browning; Fusarium wilts
Firm tuber near stolon attachment
Chemical injury
Necrotic tubers, often in bands; scablike
Coiled sprout
Swollen, curved tubers
Frozen tubers
Eyes with watery exudate
Frozen tubers
Eyes with watery exudate
Fusarium tuber rot
Rotting tissue is firm with pustules of spores on surface
Fusarium wilt; Fusarium tuber rot
Circular firm lesions, slightly sunken, relatively shallow
Gangrene
Dark colored eyes
Gangrene
Rotting lesions the size of a thumbnail becoming deep, dark cavities
Genetic abnormalities; Hair sprout; Mycoplasma
Abnormally thin tubers
Hollow heart
Center is hollow or cracked
Internal sprouting
Growth into the tuber
Jelly end rot
Watery rot at stolen end
Lightning injury
Cortex less severely rotted than medulla with possible holes through the tuber
Low storage temperature
Sugar in surface tissue
Low temperature injury
Dark tuber that is firm to soft in texture
Mycoplasma
Flaccid or wilted tubers
PLRV; Low temperature injury; Stem-end browning; PAMV
Firm interior with net scattered necrosis
PMTV
Indistinct lines, arcs, or blotchy areas as raised rings on skin
Potassium deficiency
Bronzed, necrotic leaves; downward leaf curl; underlying tissue firm, corky at stolon end
PSTV
Elongated tubers with a round cross-section
Psyllid yellows; Witches'-broom; Second growth
Lacking dormancy in tubers
Rhizoctonia
Pitted tubers
Rhizoctonia; Blackleg; Mycoplasmas
Tubers set close to stem, stolons are very short
Ring rot
Cracked skin; tuber discolored
Ring rot; Brown rot
Soft tuber that may ooze when squeezed
Second growth
Firm interior with glassy texture and a depletion of starch
Second growth; Compacted soil; PAMV; PSTV; Rhizoctonia; Mycoplasmas
Deformed tubers with irregular shapes
Second growth; Frozen tissue
Interior glassy or watery throughout or at stolon end
Second growth; Immature tubers
Starch deposition irregular to very low on tuber surface
Second growth; PSTV
Tubers with pointed eyes
Second growth; PYVV
Tubers with protruding eyes
Second growth; Secondary tubers
Forming plants prematurely or secondary tubers
Second growth; Secondary tubers; Calcium deficiency; Hair sprouts
Tuber directly forming
Stem rot
Fanlike mycelium on tuber and on soil surface; semifirm decay; cheesy rot
Sunscald
Underlying tissue collapsed on the surface and/or interior
Surface abrasions
Feathered skin
Thecaphora smut
Raised, circular lesions
TNV
Blisters on surface
TRV; PMTV
Internal arcs or rings on tubers
TRV; PMTV
Firm interior with rust colored arcs or rings
TRV; PMTV; TSWV; PAMV
Indistinct lines, arcs, or blotchy areas through the skin
Tuber cracks; Rhizoctonia; PYDV; PSTV; PMTV; TNV; Boron deficiency
Cracked skin
Verticillium wilt; Chemical injury; Stem-end browning
Netlike tuber that becomes more severe near the stolon end
Viruses; Genetic abnormalities; Nutrient imbalances
Small tubers
White mold; Fusarium tuber rot
Rot advancing with margin clearly delimited
Wind injury
Subsurface tissue is dried, soft or sunken
Witches'-broom
Many abnormally thin tubers
Witches'-broom; Psyllid yellows; Second growth
Many tubers
Cyst nematode
White to brown cysts on roots
Whole Plant
No Distinct Discoloration
Photochemical oxidant air pollution
Bronzed on the upper leaf surface and margins
PVY; PMTV; PYDV
Stunting of some stems and internodes shortened
Stem rot
Tan sclerotia; moldy surface; white at soil line; watery rot; stem collapse