Peas:Key

KEY TO PEA PESTS AND NUTRITIONAL DISORDERS

Seed

Seed disorders are limited to disorders while in the ground and not to potential disorders inherent in the seed.

BLACK

Ascochyta foot rot

Blackening at ground line and lower stem only or seed zone only

Fusarium root rot

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

BROWN

Rhizoctonia seedling rot

Bits of soil dangling from roots of freshly pulled seedlings; dark brown rotted seed; root abruptly pinched off below seed zone; poor germination; multiple coleoptiles

TAN

Pythium seed rot

Poor germination; slimy, tan, rotted seed

No Distinct Discoloration

Aphanomyces root rot

Yellowed foliage; roots diseased; vascular discoloration, if any, yellow; shrunken epicotyl

Extended cold, wet weather

Poor germination

Extended cold, wet weather; poor seed vitality; wireworm damage; fertilizer injury

Poor germination

Mechanical damage at emergence

Multiple coleoptiles

Seed corn maggot

Tunnels in germinating seeds, sometimes with maggots or pupae 4-6 mm long; poor germination

Seedling

DARK

Smog damage

Seedlings darker than normal green; leaves not expanded; slightly etiolated

GRAY

Excess moisture

Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots

Pythium seedling rot

Multiple coleoptiles; Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots; root abruptly pinched off below seed zone

GREEN

Smog damage

Seedlings darker than normal green; leaves not expanded; slightly etiolated

TAN

Excess moisture

Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots

Pythium seedling rot

Multiple coleoptiles; Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots; root abruptly pinched off below seed zone

No Distinct Discoloration

Rhizoctonia seedling rot

Bits of soil dangling from roots of freshly pulled seedlings; dark brown rotted seed; root abruptly pinched off below seed zone; poor germination; multiple coleoptiles

Root

BLACK

Fusarium root rot

Blackening at ground line and lower stem only or seed zone only

Thielaviopsis root rot

Blackening of lower stem, roots, and rootlets

ORANGE

Fusarium root rot

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

Fusarium wilt

Stunted grayish plants with upper roots and stems that, when cut lengthwise, show orange vascular discoloration extending from rootlets to taproot and upward two to four internodes into aboveground stem

RED

Fusarium root rot

Brick red discoloration in vascular tissue at seed zone when cut and examined; coloration rarely extends above ground

TAN

Aphanomyces root rot

Tan, watery roots; cortex shoughs off readily when rubbed; reduced number of rootlets; adventitious lateral roots present on hypocotyl above seed zone; yellowed foliage; roots diseased; vascular discoloration, if any, yellow; shrunken epicotyl

YELLOW

Fusarium root rot

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

Pythium root rot

Reduced number of rootlets; adventitious lateral roots present on hypocotyl above seed zone; yellowed foliage; roots diseased; vascular discoloration, if any, yellow

Rhizoctonia root rot

Yellowed foliage; roots diseased; vascular discoloration, if any, yellow

No Distinct Discoloration

Excess moisture

Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots

Minor element deficiency

No nodule formation

Nitrogen deficiency caused by limited aeration

Smooth, bright yellow, chlorotic foliage; good, clean roots

Pythium seedling rot

Multiple coleoptiles; Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots; root abruptly pinched off below seed zone

Rhizoctonia seedling rot

Bits of soil dangling from roots of freshly pulled seedlings; dark brown rotted seed; root abruptly pinched off below seed zone; poor germination; multiple coleoptiles

Stem

No Distinct Discoloration

Downy mildew

White to tan, circular spots on upper surface of leaves, with somewhat fluffy, tannish gray spores on lower surface; plants possibly stunted, with malformed foliage; moldy leaves, stems and pods when growth is dense and moisture is high

Purple blight

Brown to black-purple leaves; leaves and stems partly to all stippled from base of plant upward

BLACK

Ascochyta foot rot

Blackening at ground line and lower stem only or seed zone only

BLACK

Fusarium root rot

Blackening at ground line and lower stem only or seed zone only

BLACK

Sclerotinia rot

Moldy leaves, stems, and pods when growth is dense and moisture high; black sclerotia

BLACK

Thielaviopsis root rot

Blackening of lower stem, roots, and rootlets

BLUE

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

DARK

Ascochyta blight

Dark, irregular flecks on leaves and stems

DARK

Bacterial blight

Dark, irregular flecks on leaves and stems; angular, water-soaked, dark lesions, shiny on underside of leaf; lesions translucent when held to light

GRAY

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

ORANGE

Fusarium wilt

Stunted grayish plants with upper roots and stems that, when cut lengthwise, show orange vascular discoloration extending from rootlets to taproot and upward two to four internodes into aboveground stem

ORANGE

Drought stress

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

PURPLE

Pea streak

Purplish stem streaks; leaves dying at terminal or alternating nodes; pods often purplish or brown, pocked, often fail to fill, dry prematurely; foliage may have red-brown spots or vein discoloration

WHITE

Powdery mildew

Powdery white lesions in starlike pattern in discrete areas on upper leaf surface, stems, and pods, or encompassing entire surface areas

YELLOW

Drought stress

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

No Distinct Discoloration

Herbicide toxicity

Curled, twisted stems and growing points

Saprophytic organisms

Moldy leaves, stems, and pods when growth is dense and moisture high

Stunt

Plants stunted, with terminal rosette; foliage vein chlorosis; sometimes zones of dead leaf or stem tissue

Leaf

BLACK

Anthracnose

Oval or circular lesions with black borders and sunken, tan centers

Purple blight

Brown to black-purple leaves; leaves and stems partly to all stippled from base of plant upward

Sclerotinia rot

Moldy leaves, stems, and pods when growth is dense and moisture high; black sclerotia

BLUE

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

BROWN

Pea streak

Purplish stem streaks; leaves dying at terminal or alternating nodes; pods often purplish or brown, pocked, often fail to fill, dry prematurely; foliage may have red-brown spots or vein discoloration

Purple blight

Brown to black-purple leaves; leaves and stems partly to all stippled from base of plant upward

DARK

Ascochyta blight

Moldy leaves, stems, and pods when growth is dense and moisture high

Bacterial blight

Dark, irregular flecks on leaves and stems

MCPB herbicide toxicity

Pointed, dark, narrow leaves, cleared veins

Septoria blotch

Circular, tan lesions with dark borders and tiny pycnidia in the lesions, primarily on older, lower foliage

GRAY

Downy mildew

White to tan, circular spots on upper surface of leaves, with somewhat fluffy, tannish gray spores on lower surface; plants possibly stunted, with malformed foliage; moldy leaves, stems and pods when growth is dense and moisture is high

Drought stress

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

Fusarium root rot

Plants with grayish foliage, stunted and or dead and dying; yellow-orange vascular discoloration

Fusarium wilt

Stunted grayish plants with upper roots and stems that, when cut lengthwise, show orange vascular discoloration extending from rootlets to taproot and upward two to four internodes into aboveground stem

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

Pythium seedling rot

Multiple coleoptiles; Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots; root abruptly pinched off below seed zone

GREEN

Enation mosaic

Crinkled foliage, light-green elongate stripes following veins, sometimes showing as blisters or raised areas on underside of foliage; pods bumpy, distorted; plants stunted, severely malformed, and often killed

OPAQUE

Ascochyta leaf spot

Leaf lesions with concentric ring pattern; leaves opaque when held to light

PURPLE

Purple blight

Brown to black-purple leaves; leaves and stems partly to all stippled from base of plant upward

RED

Pea streak

Purplish stem streaks; leaves dying at terminal or alternating nodes; pods often purplish or brown, pocked, often fail to fill, dry prematurely; foliage may have red-brown spots or vein discoloration

SILVER

Thrips damage

Silver leaf lesions

TAN

Anthracnose

Oval or circular lesions with black borders and sunken, tan centers

Downy mildew

White to tan, circular spots on upper surface of leaves, with somewhat fluffy, tannish gray spores on lower surface; plants possibly stunted, with malformed foliage; moldy leaves, stems and pods when growth is dense and moisture is high

Pea leaf roll

Foliage yellowed with downward-rolled leaves, shortened internodes; upper leaves may die and turn tan

Pythium seedling rot

Multiple coleoptiles; Graying of lower leaves of seedlings, with accompanying pale tan, diffused lesions causing soft rot, lack of feeder roots; root abruptly pinched off below seed zone

Septoria blotch

Circular, tan lesions with dark borders and tiny pycnidia in the lesions, primarily on older, lower foliage

TRANSLUCENT

Bacterial blight

Angular, water-soaked, dark lesions, shiny on underside of leaf; lesions translucent when held to light

WHITE

Downy mildew

White to tan, circular spots on upper surface of leaves, with somewhat fluffy, tannish gray spores on lower surface; plants possibly stunted, with malformed foliage; moldy leaves, stems and pods when growth is dense and moisture is high

Frost damage

White lesions on foliage and pods

Hail damage

White lesions on foliage and pods

Lygus bug damage

White lesions on foliage and pods

Powdery mildew

Powdery white lesions in starlike pattern in discrete areas on upper leaf surface, stems, and pods, or encompassing entire surface areas

YELLOW

Aphanomyces root rot

Yellowed foliage; roots diseased; vascular discoloration, if any, yellow; shrunken epicotyl

Fusarium wilt

Yellowed plants with orange vascular discoloraiton extending from taproot upward, sometimes as high as blooming node

Nitrogen deficiency

Smooth, bright yellow, chlorotic foliage; good, clean roots

Pea leaf roll

Foliage yellowed with downward-rolled leaves, shortened internodes; upper leaves may die and turn tan

Pythium root rot

Yellowed foliage; roots diseased; vascular discoloration, if any, yellow

Rhizoctonia root rot

Adventitious lateral roots present on hypocotyl above seed zone; yellowed foliage; roots diseased; vascular discoloration, if any, yellow

Stunt

Plants stunted, with terminal rosette; foliage vein chlorosis; sometimes zones of dead leaf or stem tissue

Thielaviopsis root rot

Sudden yellowing of plant at blossom stage

No Distinct Discoloration

Herbicide toxicity

Curled, twisted stems and growing points

Pea leaf weevil

Uniformly scalloped lower leaves

Pea seedborne mosaic

Retarded growth and maturity, downward-rolled leaves, slightly raised vein appearance, and sometimes slight mottling; shortened internodes at advanced maturity; distorted, poorly filled, or blank pods; seeds may be misshapen, small and/or split

Saprophytic organisms

Moldy leaves, stems, and pods when growth is dense and moisture high

Sunscald

Irregular necrotic areas occurring when water is on foliage or ground in excessively hot weather

Water congestion

Collapse and disintrgration of terminal parts and margins of leaves and stipules; leaf malformation

Flower

No Distinct Discoloration

Thielaviopsis root rot

Sudden yellowing of plant at blossom stage

BLUE

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

GRAY

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

Fruit

No Distinct Discoloration

Downy mildew

White to tan, circular spots on upper surface of leaves, with somewhat fluffy, tannish gray spores on lower surface; plants possibly stunted, with malformed foliage; moldy leaves, stems and pods when growth is dense and moisture is high

BLACK

Sclerotinia rot

Moldy leaves, stems, and pods when growth is dense and moisture high; black sclerotia

BLUE

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

BROWN

Pea streak

Purplish stem streaks; leaves dying at terminal or alternating nodes; pods often purplish or brown, pocked, often fail to fill, dry prematurely; foliage may have red-brown spots or vein discoloration

GRAY

Gray mold

Blue-gray, fuzzy fungus growth on leaves, stems, blossoms, and/or pods; diseased areas become necrotic

GREEN

Lima bean pod borer

Small circular holes in green pods, with damage to peas

PURPLE

Pea streak

Purplish stem streaks; leaves dying at terminal or alternating nodes; pods often purplish or brown, pocked, often fail to fill, dry prematurely; foliage may have red-brown spots or vein discoloration

WHITE

Frost damage

White lesions on foliage and pods

Hail damage

White lesions on foliage and pods

Lygus bug damage

White lesions on foliage and pods

Powdery mildew

Powdery white lesions in starlike pattern in discrete areas on upper leaf surface, stems, and pods, or encompassing entire surface areas

No Distinct Discoloration

Ascochyta blight

Moldy leaves, stems, and pods when growth is dense and moisture high

Enation mosaic

Crinkled foliage, light-green elongate stripes following veins, sometimes showing as blisters or raised areas on underside of foliage; pods bumpy, distorted; plants stunted, severely malformed and often killed

Marsh spot (manganese deficency)

Large, usually misshapen seed with hollow center

Pea seed weevil damage

Small, discrete, circular holes in seed with a hollow center

Pea seedborne mosaic

Retarded growth and maturity, downward-rolled leaves, slightly raised vein appearance, and sometimes slight mottling; shortened internodes at advanced maturity; distorted, poorly filled, or blank pods; seeds may be misshapen, small and/or split

Saprophytic organisms

Moldy leaves, stems and pods when growth is dense and moisture high