In August 2015, a 10-day field trial was carried out with some success.Īs concern surrounding CRB mounts, the U.S. Small radio transmitters are glued to adult rhino beetles, these are then released and tracked back to previously unknown breeding sites. More recently, new radio tracking technology has been proposed as a more cost-effective alternative. This method, however, proved expensive and hard to reach areas were beyond its capability. Previously, specially trained detector dogs were used to root out rhino beetle breeding sites. However, this task proves tricky on a 210 square mile island covered in dense jungle and off-limits military bases. #GUAM COCONUT RHINOCEROS BEETLE FREE#General sanitation practices that involve keeping areas free of green waste help to reduce the number of breeding sites, invariably limiting the potential for CRB population growth. Unfortunately, it has not proved as effective as once thought and the Guam beetle population persists at damaging levels. The fungus is specific to rhino beetles and the CRB-Guam biotype appeared susceptible to it. In March 2012, the Plantwise Knowledge bank reported on a promising new biological control method, the Metarhizium fungus. Numerous management techniques have been attempted on Guam since 2007. A positive feedback system may be initiated whereby more breeding sites allow for larger populations which kill mature palm trees which, in turn, become breeding sites for subsequent generations. Downed trees and vegetative waste make ideal breeding sites for the beetle. The passing of Typhoon Dolphin over Guam in 2015 highlighted the dangers of an event like this triggering rapid growth in CRB populations. Smaller islands, where traditional, palm-dependent economies still operate, stand to suffer the most.įigure 1: “ The CRB-Guam biotype has invaded five Pacific Island countries and territories in only eight years compared to the CRB-Pacific biotype, which has not had geographical range expansion for 40 years“ There is now a real threat of a Pacific-wide outbreak of CRB. As well as Guam, the new biotype has now been logged in Papua New Guinea (2009), Palau (2014), Hawaii (2014) and the Solomon Islands (2015) (see figure 1). This resistance has proved paramount to the invasive ability of CRB. The Guam population was deemed a new biotype (CRB-Guam) and was found to be resistant to all available OrNV strains. Upon DNA analysis, the invading rhino beetles were found to be genetically distinct from CRB native to other Pacific regions. Early attempts at disseminating the virus in the new Guam population proved surprisingly ineffective. Up until Guam, 2007, it had been 40 years since an outbreak of CRB on an uninfested palm growing Pacific island, owing to the persistence of OrNV in beetle populations. As a biological control strategy, it has been highly effective at keeping CRB populations low and thus lessening palm damage by up to 90% ( Bedford, 2013). The principal method of rhinoceros beetle control is through the release of a virus specific to CRB known as Oryctes rhinoceros nudivirus (OrNV). A coconut palm damaged by CRB © Aubrey Moore
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