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).
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).Pheromonal Control
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).Cultural Control