Red palm weevil is a serious pest on palms trees. The caterpillar starts feeding on the frons at the top of the shoot causing several damages. The symptoms are:
a) Oozing of brownish sap from the central infested parts of the trunk.
b) Central shoots of the crown region begin to wilt.
c) Inner leaves at the crown region turn yellow.
d) At initial stages of infestation, leaf damage results in browning of affected leaves.
e) Oozing of brown sap may also be seen from holes in the trunk region.
Control measures:
The pest feeds at tip of the crown which is located at height makes it impossible for complete eradication. The difficult in accessing the larvae (grubs) which are active feeders poses the biggest challenge for controlling the pest. However, several measures, if implemented in a concerted manner, would help in combating the pest damage to coconut.
Integrated Pest Management for Treating Red Palm Weevil.
1) Avoiding injuries to the trunk region since wounds attract the female weevils and serve as oviposition sites.
2) Closing the feeding holes on the trunk with clay or cement.
3) Removal of damaged and wilting palms at regular intervals and burning these debris would destroy the pest eggs and prevents their perpetuation.
4) Cutting of health green palms should be avoided as it renders the plant weak by reducing the photosynthesis. If need be, they should be cut at a length of 120 cm away from the crown or main stem.
5) Filling the crown and base of top fronds with a mixture of sand and neem seed powder or neem seed kernel powder (2:1) preferably at monthly intervals. This would be effective in deterring the adult females from egg laying at the crown region and also damage by the Rhinoceros beetle, yet another pest of coconut.
6) Fermentation process and fermenting odour in turn is known to attract the adults of Red palm weevil. Mix sugarcane molasses (2½ kg) OR toddy (2½ litre) with yeast (5.0 g). Keep the mix in mud pots. Keep longitudinally split tender green fronds with leaves in each pot which act as adult traps. Distribute 30 traps in one acre area.
7) Install 2-3 pheromone traps per acre.
8) Manual collection of eggs, adults, pupa and larva and destroying them in dipping in kerosene or hot water also is a viable option.
9) Maintain good sanitation in the field by removing all types of debris (fronds, sheaths, leaves, etc. which act as refuge for the pest).