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Rhinoceros beetle (palm pest)

The coconut rhinoceros beetle (Oryctes rhinoceros) is a major boring pest of coconut, oil palm, date palm and other large palms across South and South-East Asia. Adult beetles bore into the crown of the palm, where they feed on soft tissues and damage the developing leaves.

Identification and symptoms

Adults are large, dark brown to black beetles, 35-50 mm long, with a forward-projecting horn on the male's head. They bore into the unopened spear and central whorl of the crown, where they feed on developing leaf tissue. As the affected leaves unfurl, they show characteristic V- or diamond-shaped cuts. Frass and fibrous chewed material accumulate at bore holes.

Host crops and life cycle

The beetle attacks coconut (Coconut Ceylon Yellow, Coconut Kerala Bondam Dwarf), oil palm, date palm and other large palms. Larvae develop in decaying organic matter such as coconut logs, manure pits, sawdust heaps and abandoned silage. The life cycle takes around 4-6 months under tropical conditions.

Damage and economic impact

Heavy attack can kill young palms outright and reduces yield in older palms by destroying spear leaves and creating entry points for the more lethal red palm weevil (Red Palm Weevil). The pest is therefore controlled both for direct damage and for its role in palm-weevil dynamics.

Management

ICAR-CPCRI's integrated programme combines:

  • Mechanical: hooking of adults and grubs from breeding sites and from crowns.
  • Cultural/sanitation: removal and proper composting of breeding substrates (decaying palm logs, manure heaps); leaf-axil filling with sand or neem cake to repel egg-laying females.
  • Biological: soil application of the entomopathogenic fungus Metarhizium anisopliae; release of beetles infected with Oryctes rhinoceros nudivirus to spread infection in wild populations.
  • Trapping: pheromone bucket traps baited with ethyl 4-methyloctanoate (E4-MO) at 1-2 km between traps in hot spots.

Combined with red palm weevil management (Red Palm Weevil), this approach protects palms whose husks ultimately feed the coir industry (Coir Cocopeat Industry).

See also: Red Palm Weevil, Coconut Ceylon Yellow, Coconut Kerala Bondam Dwarf, Coir Cocopeat Industry.

References

  1. Pests of Coconut: IPM for Oryctes. Springer.
  2. Research Achievements - Crop Protection. ICAR-CPCRI.