|
September 2015. A new strain of rhinoceros beetle discovered on Guam.
A member asked about Metarhizium and whether that is also part of the of plan to prevent large scale damage due to the beetle. There was concern raised by staff in Kiribati. The identification of the new strain was done by AgResearch, New Zealand (In PNG, the work was done in association with the PNG Oil Palm Research Association and NAQIA).
There is an SPC alert here: http://www.spc.int/lrd/plant-health-publications/cat_view/137-all/128-plant-health-/277-pest-alerts?start=50
And there is a report in the SPC LRD Newsletter of the beetle in Solomon Islands (see below).
A note on the naming of the biotype: The term “CRB Guam biotype” was coined when the beetle was found on Guam to have a distinct genotype (among about five genotypes found in the few populations for which there is DNA). It is resistant to all strains of OrNV currently available, and appears to cause more damage per capita than CRB in other populations. The term was invented to express these differences between CRB on Guam and CRB elsewhere and has no has no further biological significance at this point in time. It was later found that all new invasions of CRB share the Guam genotype, and it is assumed that these are CRB-G even though tolerance to OrNV has not yet been tested on individuals from these populations.
A member from Palau pointed out that although the more aggressive virus-resistant strain is present there, damage by coconut rhinoceros beetles is not particulalry severe. Damage does occur, and about 75% of the coconuts show symptoms, but damage is minimal. It is unusual to see a coconut that has been severely damaged and/or killed by the beetle in the main islands of Palau. Perhaps something can be learned here that can help other Pacific Islands.
Interestingly, Bernhard Zelazny, who had previously worked on Oryctes in the Philippines wrote to PestNet saying that a biotype with a tolerance to the baculovirus was known when he was working there in the 1980s. Whether that is the same as the Guam isolate or the latter has arisen independently will not be known until DNA analysis of the beetle throughout its range has been completed. The abstract of the FAO paper is provided below.
|
