Mexican bean beetle larva MER copy.jpg

Mexican bean beetle grub


  • Adult: Oval-shaped beetle that is yellow to orange-brown with eight black spots on each wing cover.
  • Larvae: Tiny, greenish-yellow, soft-bodied and spiny.
  • Eggs: Pale yellow to orange and laid in clusters on the undersides of bean leaves. 

Timing of damage: V1 to R7

Type of damage: Both larvae and adults skeletonize bean leaves. Adults will also feed on pods.

Scouting: Examine five plants in five areas of the field to determine percentage of defoliation.

Economic threshold: In V stages: 40% defoliation. R1 to R5: 15% defoliation. R6 to harvest: 25% 
defoliation and beetles or larvae are actively feeding.

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