Lecture note on Rhynchophorus ferrugineus

Rhynchophorus ferrugineus
The common red palm weevil. Adult weevil is reddish brown in colour. Its body is almost cylindrical, with long and slender snout, and six dark spots on the thorax.
Life cycle:
Life cycle is completed within the host plant itself. It involves indirect development and complete metamorphosis. Female lays eggs either in the scooped out pits, or in the holes, cuts and wounds in the palm. Within 2-5 Days yellow-coloured larvae (grubs)emerge. They feed on the soft tissues of the palm and grow in size. Larval life lasts for 40-80 days. Towards the end of it, larvae pupate within fibrous cocoons inside the palm.After 12-30 days of pupal life, pupae transform to adult weevils. Fully grown adults come out for mating
Damage
Rhynchophorus is a highly destructive and persistent pest of coconut palms. It infests the crown either by boring through the soft parts, or by entering through the holes and cuts already present. It infests the trunk by getting into the interior through holes cuts. Its larvae and adults feed on the palm tissues and make tunnels inside. In cases attack, the interior of the palm gets crowded with adults, larvae pupae of the weevil. This causes the drying of the central shoot leading to the and of severe and advanced and wilting and ultimate death of the palm. The presence of small holes in the stem from which chewed fibres protrude and a thick brown liquid oozes is a clear indication of infestation.
Control measures
(i)Injection of carbontetrachloride or the emulsion of pyrethrum, sevin, etc. through the holes into the interior of the palm to kill grubs, pupae and adults.
(ii) Fill the leaf axils of the crown with a mixture of BHC and sand.
(iii) Kill the grubs and pupae by stabbing with sharp iron spikes.
(iv) Burn off severely affected palms.
(v) Scoop out the infested portion and dress it with tar.
(vi) Restrict or avoid the practice of making cuts and injuries on palms.
(vii) Biological control by using the dipteran fly Cheliosoches mori which preys on the eggs and grubs of the palm weevil.