Dry Beans

Pests and their Damage to Plants—Bud through Bloom

On this page
  • Charcoal rot
  • Pythium spp.
  • Fusarium root rot
  • Fusarium wilt
  • Nematodes
  • Alfalfa mosaic virus
  • Bean yellow mosaic virus
  • Bean common mosaic virus
  • Armyworms
  • Loopers
  • Saltmarsh caterpillar
  • Cucumber beetles
  • Leafminers
  • Aphids
  • Common bacterial blight
  • Spider mites
  • Leafhoppers

Collapsed, wilted, dying
Yellowing, mottled, distorted leaves
Leaves with holes
Leaves with mines

Curled leaves
Leaves with spots
Leaves with stippling

Use the photos below to identify damage. Names link to more on identification and management.

Click on photos to enlarge
Collapsed, wilting, stunted, or dying plants

Charcoal rot
Charcoal rot damage
Identification tip: Charcoal-like dust on stem surface.

Pythium spp.
Pythium spp. (blackeyes) damage
Identification tip: Blackeye bean stem tissue dries out, becomes sunken, and turns tan to brown in color when infected.


Fusarium root rot
Fusarium root rot damage
Identification tip: Brick-red lesions of variable size on belowground stems, tap roots; red lesions turn brown; small red flecks under scraped lesion surface.

Fusarium wilt
Fusarium wilt (of blackeyes) damage
Identification tip: Pale green, flaccid leaves turn yellow and drop off; brown discoloration in center of root, stem, and some branches (seen when sliced).

Nematode damage
Identification tip: Wilted and stunted plant has root galls (right) compared to healthy plant (left).

Yellowing, mottled, distorted leaves

Alfalfa mosaic virus
Alfalfa mosaic virus
Identification tip: Yellow leaf mottling.

Bean yellow mosaic virus symptoms
Bean yellow mosaic virus damage
Identification tip: Infected leaves bright yellow to green mosaic, or mottled; leaves distorted, cupped downward, and wrinkled; differs from bean common mosaic virus symptoms, which cause light and dark green mosaic leaf patterns.

Bean common mosaic virus
Bean common mosaic virus
Identification tip: Green-yellow and dark green mosaic pattern on leaves; discoloration usually accompanied by puckering, blistering, distortion, downward curling.

Cowpea leaves showing mosaic pattern and mottling, symptoms of Cucumber Mosaic Virus, Cucumovirus CMV.
cucumber mosaic virus
Identification tip: Symptoms vary considerably from a light-green to dark-green mottle, blisters and vein banding, interveinal yellowing and leaf distortion.

Leaves with holes; skeletonized leaves

Armyworm damage
Armyworm young larva and damage
Identification tip: Newly hatched larva scrapes leaf tissue, "skeletonizing" leaf.

Armyworm damage
Armyworm older larva and damage
Identification tip: Older larva chews large sections of leaves.

photo of looper damage
Loopers damage
Identification tip: Chew holes in mature leaves.

Cucumber beetle
Cucumber beetle adult and damage
Identification tip: Chews holes in leaves.

Saltmarsh caterpillar
Saltmarsh caterpillar young larvae and damage
Identification tip: Young larvae feed in groups, chewing holes in leaves. Older larvae (not pictured here) feed individually.
Leaves with mines

Leafminer damage
Leafminer damage
Identification tip: Wavy tan leaf mines in surface of bean leaves.


Curled leaves

Aphid damage
Aphid damage
Identification tip: Curled, sticky, and shiny leaves, sometimes with black sooty mold.

Cowpea aphid
Cowpea aphid adults
Identification tip: Shiny black. Legs and antennae white to pale-yellow with black tips.

Bean aphid damage
Bean aphid adults
Identification tip: Slightly larger than the cowpea aphid; dark olive green to black with light-colored legs.

Foliage damaged by curly top virus.
Curly top
Identification tip: Puckered, wrinkled, dark green leaves with edges curled downward. The internodes become shortened, resulting in stunted plants.

Leaves with spots

Common bacterial blight
Common bacterial blight damage
Identification tip: Irregularly shaped spots bordered by a lemon-yellow ring; as spots enlarge, tissue in center dies and turns brown.

Alfalfa mosaic virus
Alfalfa mosaic virus
Identification tip: Yellow leaf mottling.

Water soaking and necrosis on bean leaves, due to bacterial brown spot caused by Pseudomonas syringae pv. syringae.
Bacterial brown spot
Identification tip: Oval spots with dead tissue in the center surrounded by a narrow zone of light-green tissue. The centers of the spots may fall out resulting in tattered appearance.

Halo blight symptoms on bean leaves.
Halo blight
Identification tip: Small, angular, water-soaked spots on the undersurfaces of leaves turn brown and develop characteristic light green to yellow halo around.

Leaves with stippling

Spider mite damage
Spider mite damage
Identification tip: Very fine white or yellow stippling; fine webbing on leaf undersurface.

Leafhopper damage
Leafhopper damage
Identification tip: White stippling on upper surface of leaves; small white cast skins, tiny dark varnishlike spots on undersurface of lower leaves.

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