The damage of all the strains is similar, but there has been speculation that CRB-G is tolerant to OrNV, and that it is more aggressive. This is particularly important as new strains of the beetle have been found in Pacific islands in recent years, in addition to the original strain, CRB-S (also known as CRB-P), that has been present for more than 100 years. CRB-G is now present in Guam, Palau, Papua New Guinea, and Solomon Islands, and CRB-PNG in the islands of Papua New Guinea and Solomon Islands. Establish pheromone traps and regularly inspect coconut palms growing nearby for frass and leaf symptoms. Apply control measures if 3-5 beetles occur per ha up to 2 years after planting, and 15-20 beetles per ha thereafter.īIOSECURITY Vigilance is needed at seaports and airports against hitchhiking beetles. A fungus, Metarhizium anisopliae, from the Philippines is also used. Today, the key agent is a virus ( Oryctes rhinoceros nudivirus - OrNV) originally from Malaysia. Research into management of Oryctes started in the Pacific islands in the 1960s. Differences between the strains depends on molecular tests. Use a hooked wire inserted into the tunnel to remove the beetle. Look for tunnels in the crown of coconut palms with frass - often more than one per palm. Look for large jet-black beetles up to 40 mm long with prominent horns. In Asia and parts of Papua New Guinea, Oryctes attack encourages invasion by Rhynchophorus sp. Using the relationship between damage and yield calculated elsewhere, work in Samoa showed that a 25% reduction in leaf area resulted in a 25% reduction in nut yield. One way is to prune leaves to simulate beetle attack and compare nut yields on healthy palms. It is difficult to relate damage to lost production. Occasionally, the beetles bore through the midribs of fronds, which snap in the wind. The damage caused by the beetle results in loss of leaf area, flowers dying, early nut fall and, ultimately, lower yields. Spread is on the wing, they are stronger flyers, and aboard ships and aircraft. They do not eat the frass from the tunnels instead, they drink the sap that comes from tunneling. The beetles are nocturnal, flying to the tops of coconuts where they use their mandibles, horn and strong forelegs to tunnel into the crowns. Females live about 9 months, and lay about 50 eggs males live about 5 months. They are black with horns - those of the female often shorter than the male (Photos 9-12). The two pupal stages last 25-40 days.Īdults remain in the ground for 2-3 weeks and then chew their way out. The last stage makes a hollow where it feeds, lining it with liquid faecal material, and then pupates. There are three stages lasting 80 to 200 days (depending on quality of the diet), with the third stage up to 100 mm long and 20 mm diameter. The C-shaped larvae or grubs are white then creamy with brown heads (Photo 8). Logs and stumps of many other kinds of trees are also hosts (Photo 7). Oval eggs (3.5 x 4 mm) are laid one at a time, 5-15 cm, below the surface of moist organic materials, such as sawdust, manure, compost and garbage heaps, or above ground in tunnels, debris in axils of coconut fronds, in still-standing but dead and rotten coconut palms, and in the rotten ends of fallen coconut trunks (Photo 6). Holes in the base of the fronds may be obvious when beetle populations are high (Photo 5). When the leaves unfold the damage is seen as V or wedge-shaped areas missing from the leaflets (Photos 1-4). The adult beetle does the damage, boring into the crown of coconut palms, cutting across young fronds and flowers. Banana, Pandanus, sugarcane and tree fern are also hosts. HostsĬoconut is the most important host, but other palm species are attacked, including betel nut, sago palm and oil palm. South and Southeast Asia, Oceania. American Samoa, Fiji, Hawaii, Papua New Guinea, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, and Wallis & Futuna. Recently, the beetle has spread to Guam, Hawaii, mainland Papua New Guinea, Solomon Islands, and Vanuatu (under eradicatiion). Common NameĬoconut rhinoceros beetle, rhinoceros beetle Scientific Name An artifical breeding site inoculated with spores of Metarhizium anisopliae, in order to infect larvae of the rhinoceros beetle, Oryctes rhinoceros (Fiji).
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