Primarily found attacking coconut and oil palm, O. rhinoceros has also occasionally been recorded on banana (Sharma and Gupta, 1988), sugarcane, papaya, sisal and pineapple (Khoo et al., 1991). In Mauritius, ornamentals such as the royal palm (Roystonea regia), the latanier palm (Livistona chinensis), the talipot palm (Corypha umbraculifera) and the raphia palm (Raphia ruffia) are attacked (Bedford, 1980).

• Adults feed in the crown region of coconut
• Multiple attacks in a same palm subsequently produce fronds which have wedge-shaped gaps or the characteristic V-shaped cuts to fronds (Wood, 1968a; Sadakathulla and Ramachandran, 1990).

Palm damaged by the beetle

A method for trapping adults has been developed and tested by Hoyt (1963) and Bedford (1973). Hoyt (1963) designed a simple, cheap trap, consisting of a piece of coconut trunk, the cap with a beetle-size hole drilled through the centre, and resting on a tin can a tin can placed right below it leaving no space between them. The whole trap is set at a height of 1.8 m from the ground. There was no chemical attractant used in this trap: the decaying trunk served as the attractant. When a small quantity of the synthetic chemical attractant ethyl dihydrochrysanthemumate (chrislure) was applied to the coconut cap of the Hoyt trap, catch was increased (Bedford, 1973) compared to dispensing the lure from a more expensive metal vane-type trap (Barber et al., 1971).

A male-produced aggregation pheromone, ethyl 4-methyloctanoate (E4-MO) was discovered (Hallett et al., 1995; Morin et al., 1996). It has been synthesised and is available commercially (for details of synthesis and types of traps available, see Bedford (2013a)). It is reported to be 10 times more attractive than ethyl chrysanthemumate. The pheromone is stored in a small, heat-sealed, polymer membrane bag and placed between interlocking metal vanes mounted on a plastic bucket. The beetles attracted by the pheromone are trapped inside the bucket. It is very useful as a monitoring tool, and as an economical control method particularly in young oil palm replant areas when placed at one trap per 2 ha (Norman and Basri, 2004; Oeschlager, 2007; Bedford, 2014).

• Sanitation within and surrounding the plantations, especially destruction of the potential or existing breeding sites of this pest (Wood, 1968a; Turner, 1973).
• Manure heaps and pits may have to be covered or alternatively turned regularly for the removal of the grubs (Catley, 1969).
• Removal of the adults from the point of attack in young palms by using a hooked piece of wire (winkling).

• Early attempts at biological control of O. rhinoceros concentrated on the introduction of predators and scoliid parasitoids of other Oryctes species mainly from Africa.
• Biological control effort concentrated on Oryctes rhinoceros nudivirus (OrNV) after its discovery in Malaysia in 1965 (Huger, 1966) and its successful introduction into Western Samoa in 1967 (Swan, 1974; Waterhouse and Norris, 1987). For OrNV, the adult beetles are dipped in a suspension of ground, infected grubs. They are then allowed to crawl about for 24 hours through sterilized sawdust mixed with the above suspension. They are then released back into the plantation to infect other adults and larvae in the breeding sites (Bedford, 1976d).
• OrNV suspension may also be applied directly to the mouthparts of adults to infect them for release (Ramle et al., 2005). A supply of beetles for infecting and release may be obtained from a mass-rearing facility.
• The fungus Metarhizium anisopliae var. major may be produced commercially or in bulk by various methods, for release by suitable means into breeding sites, particularly into chipped decaying oil palm trunk material in oil palm replant areas (Sivapragasam and Tey, 1995; Tey and Ho, 1995; Ramle et al., 1999, 2006, 2007, 2009, 2011; Ramle and Kamarudin, 2013).

• The point of chemical application is at the base of the leaf sheath (Sadakathulla and Ramachandran, 1990).
• Granular formulations of the insecticide gamma-BHC were effective as this facilitates applying them in the frond axils and thereby lowering costs compared to spraying liquid formulations (Ho and Toh, 1982).
• The use of long residual insecticides for drenching the breeding sites (i.e. coconut stumps) has been found effective to suppress the larval stages up to 7 months (Ho and Toh, 1982).
• Insecticidal treatment at the bottom soil of manure pits may also be useful to suppress the larval stages (Visalakshi et al., 1988).