Pest :Cockchafer beetles (Coconut root grub)

Adult is a shiny deep reddish brown beetle; 30 mm in length and 14 mm broad. The elytra is longitudinally striated and does not cover the abdomen fully.The beetle has long hairy legs.The pest is mostly found in sandy loam tracts of Kerala.


  • In seedlings, grubs of the beetles tunnel in to the boles and collar region.
  • It feeds on roots of coconut trees resulting in yellowing of leaves, immature nut fall and delaying of flowering.
  • The infested trees show sick appearance with the stem tapering towards the crown.

Procedure for Observation

Open up the soil around the trees showing yellowing symptoms (5 trees in a garden) during early morning and record the population of grubs feeding on roots. Work out the average.


10 grubs per tree.

Control Measures

  • Collect and destroy adults during the monsoon period in the evening from adjacent vegetation.
  • Plough or dig the infested soil synchronizing with pre monsoon showers.
  • The exposed grubs will be eaten away by natural enemies such as birds,dogs, cats ,etc
  • Drench the soil with chlorpyriphos 0.04 % (2 ml/lit).
  • The treatment should be given twice-first during April to May after the receipt of pre monsoon showers and second during the month of September.
  • Set light traps where ever possible to attract and trap adult beetles.