Previously, granular insecticides were placed in the axils of the fronds. It has still to be put to use in estate and smallholder plantations. It is said to be easy to make and is cheap. In Papua New Guinea, fewer palms of the Gazelle Tall died from attack compared to Rennell Tall or Malayan Dwarf.ĬHEMICAL CONTROL Chemical control of this pest is very difficult and not recommended under small-scale production systems.Ī pheromone has been isolated and used in mass trapping trials in Papua New Guinea. RESISTANT VARIETIES Fast-growing varieties are more likely to outgrow the damage caused by the beetles. Plant Pueraria phaseolodes, Mucuna pruriens or other legume species as soon as the trees have been felled to cover the logs and stumps in order to interrupt egg laying.Remove or burn breeding sites, large logs in particular (a difficult practice for small holders when clearing sites from forest).

If possible replant coconuts within existing coconut plantations, where it might be expected that potential breeding sites for Scapanes would be low.

Its success against Scapanes is limited by the dispersed distribution of the larvae. There have been no attempts at biological control although Scapanes is susceptible to Oryctes rhinoceros nudivirus which has been used against Oryctes rhinoceros. It is mainly a grower-made problem due to planting coconuts in recently cleared forests. NATURAL ENEMIES As Waterhouse and Norris say in Biological Control Pacific Prospects, 'Scapanes is not an attractive target for biological control'. ManagementĬontrol of Scapanes is difficult as they can cause substantial damage even though the numbers of adult beetles per hectare is relatively low. In the field, inspect the crown of the palms, looking for V-shaped cuts in the leaves, distorted fronds and fibre pushed from the tunnels into the crown. There could be confusion with Oryctes rhinoceros, but that attacks much older palms. Look for the horns on the adult male beetles, they are characteristic, whereas females may be more difficult to recognize. Keep them in a sterilised cow dung and sawdust mixture. However, for correct identification, they need to be bred to adults, as they are similar to other beetles in the scarab family. Look for the larvae beneath rotting logs. However, as the logs rot away, and there are less breeding sites, the attack decreases. All the palms may be damaged within 5 years, discouraging farmers from planting or replanting coconuts. Impactĭamage can be severe when coconuts are planted in land cleared from forest, where the rotting logs provide breeding sites. Males and females have been seen in the same tunnel in the crown of a coconut, but it is the male alone that is seen most commonly. Males are horned (Photo 3) while females have small double horns on their heads. Adults are black, 4-6 cm long, and are strong fliers. As the larvae grow, they moult twice, reaching 10 cm in length and 2 cm wide, before pupating at about 9 months. Breeding sites have also been found in old nests of magapodes, when these were near breadfruit trees.Įggs hatch after about 30 days producing C-shaped larvae (Photo 2), with heads of reddish-brown to brown.

In Papua New Guinea, breeding sites occur in cocoa and coconut plantations associated with rotting stumps of shade tree (e.g., Gliricidia sepium). The eggs are creamy-white, about 5 mm long and 3 mm diameter, laid singly in soil near rotting logs or other decaying matter that provides food for the larvae.

The damage allows entry of other organisms: termites and, especially, Rhynchophorus weevils. If the growing point is damaged, the palms die. The emerging fronds show V-shaped cuts, twisting, spiraling and truncated leaflets. Damage to coconuts is considerable, especially up to 5 years' old. The adults bore into crowns of coconut, oil palm, betel nut, and other palm species, as well as pseudostems of bananas (Photo 1). The main hosts are coconut, oil palm and betel nut, but the beetle is also found on banana, sugarcane and wild palms. It is recorded from Papua New Guinea and Solomon Islands. Different sub-species ( Scapanes australis australis and Scapanes australis grossepunctatus) exist in Papua New Guinea the situation in Solomon Islands has not been studied. Melanesian rhinoceros beetle, coconut rhinoceros beetle, Scapanes Scientific Name

Coconut rhinoceros beetle control