Pests & diseases › Mexican Bean Beetle

Mexican Bean Beetle

Yellow-orange beetle that looks like a ladybug but with 16 black spots. Larvae are yellow spiny grubs. Devastates bean foliage.

Symptoms

  • Lacy skeletonized bean leaves
  • Yellow spiny larvae on leaf undersides
  • Cluster of bright yellow oval eggs on leaf undersides
  • Pods scarred where larvae feed

Lifecycle

Adults overwinter in debris. Two or three generations per season.

What to do

  • Hand pick adults, larvae, eggs
  • Insecticidal soap on young larvae
  • Spinosad
  • Beneficial parasitic wasp Pediobius foveolatus (released commercially)

If it's bad

  • Pyrethrin

Stop it coming back

  • Clear debris in autumn
  • Floating row cover early in season
  • Resistant varieties (limited): Wade, Logan

Crops it goes for

Plan the plot, track every sowing, cook the harvest

Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.