Symptoms
- 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.
ETL
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.