Invasive biotype of CRB damaging for country

Director Division Resources Terrestres (SPC) Mr Jan Helsen.
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Director Division Resources Terrestres (SPC) Mr Jan Helsen.

PACIFIC livelihoods and economies reliant on coconuts, oil palm and other palm species are under threat of an invasive biotype Coconut Rhinoceros Beetle (CRB).

According to Dr. Jan Helsen, Director of the Pacific Community (SPC) Land Resources Division, the new biotype of Coconut rhinoceros beetle (CRB), Oryctes rhinoceros was first discovered in Guam in 2007.

He said this biotype known as CRB Guam (CRB-G) is highly invasive with the ability to cause significant damage to palm trees. It can also rapidly adapt to its environment. Since its discovery, new invasions have been recorded on the Papua New Guinea (PNG) mainland (2009), Hawaii (2014), Palau (2014) and Solomon Islands (2015).

Helsen said that CRB Guam is resistant to known isolates of the Oryctes nudivirus (Or NV) which had previously proven effective against the CRB-Pacific (CRB-P) biotype.

He said that study of palms in CRB ‘hot spots’ with uncontrolled breeding sites yielded the following comparative results between the CRB-P and CRB-G biotypes, that is, that the CRB has a long life cycle of around 180 days.

“The adult beetles live up to 9 months, causing damage by chewing into the growing shoot of the palms, which results in the V-shape notches on the leaves after they unfurl, this is only noticeable sometime up to 4 months after the damage has been caused.

“Intensive feeding damage can also causes eventual death to the palms” he said.

He adds that the Tree mortality occurs when beetles destroy the growing tips (meristems) of palms in the immature stages and that the grubs feed on compost materials.

He further adds that the spread of CRB between islands, is highly dependent on human mediated activities.

‘’Soil and plant materials can contain the immature life stages of the beetle. The beetles are attracted to light from boats and planes, which can then transport them to new locations. Detection of first incursions usually results from evidence of physical damage symptoms on palm leaves” he said.

In the meantime Dr Jan said that Management initiatives to suppress CRB populations in infested sites may include; crop sanitation, pheromone trapping, biological control agents, cover-cropping, insecticide application and physical killing of beetles.

“The use of pheromone trap technology is common for CRB surveillance and National Biosecurity Authorities are encouraged to use them for early detection and monitoring programmes” he adds.