Rhinoceros beetle is mainly a pest of coconut and oil palms.

The beetles damage palms by boring into the centre of the crown, injuring the young growing tissues and feed on the exuded sap.

As they bore into the crown, they cut through the developing leaves. When the leaves grow out and unfold, the damage appears as V-shaped cuts in the fronds or holes through the midrib.

Life cycle

Eggs are laid and larvae develop in manure pits or other organic matter and hatch in 8-12 days.

The larvae stage takes another 82-207 days before entering an 8-13 day non feeding prepupal stage. The pupal stage lasts for 17-28 days.

Adults remain in the pupal cell for 17-22 days before emerging and flying to palm crowns to feed. They are active at night and hide in feeding or breeding sites during the day.

Mostly mating takes place at the breeding sites. Adults may live for 4-9 months and each female lays 50-100 eggs during her lifetime.

Management methods:

— Chop and burn decaying logs or break them up and destroy any adult beetles developing inside. Cut stumps as close to the soil surface as possible.

— A hooked wire can be used to extract and destroy rhinoceros beetle adults feeding in coconut trees.

Fungal application

— The fungus, Metarhizium anisopliae can be applied in manure pits at 4 kg/tonne to control the grubs that feed on the decaying matter

— Apply mixture of neem seed kernel powder + sand (1:2) at150 g per palm in the base of the 3 inner most leaves in the crown

— Place phorate 10 G 5 gms mixed with sand in two inner most leaf axils for 2 times at 6 months' intervals. Place some napthalene balls at leaf axil at the top of the crown

— Use pheromone traps with rhinolure @ 12/ha for trapping the adults and destroy them.

— Treat the longitudinally split tender coconut stem and green petiole of fronds with fresh toddy and keep them in the garden to attract and trap the beetles.

A.Suganthi and A.P. Sivamurugan,

KVK, VirinjipuramTamilNadu Agricultural University, Vellore