African rhinoceros beetle (Oryctes monoceros)
It is a stout beetle, about 3.5 to 5 cm long, shiny dark brown to black in colour with a curved horn on the head, hence its common name. The adult flies at night to palms and bore into the hearth of the palms spear, chewing and cutting the youngest unopened leaves and the vegetative bud.
Attacked leaves continue to develop and unfold showing a characteristic V-shape damage. If the whole growing point is eaten, the palm usually dies, particularly young palms less than four years old. The boreholes are often marked with a bundle of fibres pushed out of the hole by the beetle. This beetle is a serious pest in plantations where field sanitation is neglected. Eggs are laid in rotting plant material, especially dead palm trunks, compost heaps and rubbish dumps. The larvae (grubs) and pupae develop in rotten coconut logs and other decaying material.
- Fell, chop and remove dead palms to eliminate breeding sites.
- If logs cannot be removed, check the decaying end. Collect and destroy grubs.
- Hook out beetles in young palms. A 30 cm long iron rod with a hook at one end is pushed into the tunnel bored by the beetle while feeding. If the beetle is still inside it will be hooked out.