CRB arrival and spread on the Papua New Guinea mainland in Madang and Morobe provinces

Despite the presence of Oryctes rhinoceros (coconut rhinoceros beetle; CRB) in the New Guinea Islands, Papua New Guinea (PNG) since the 1940s, the mainland of PNG remained free from the pest until recently. While CRB was reported from Port Moresby in 2009, the first report of CRB from the Northern provinces was recorded from the Markham valley in 2018. In September 2019, CRB was reported from coconut groves at Kananam Village on the northern coast of Madang Province. Haplotype analysis showed that the earliest records were CRB-S (clade II), similar to beetles found in the New Guinea Islands. CRB-S has now been found from Madang to Malala along the coast. More recently, CRB-G (clade 1b) has also been encountered in populations around Kananam village. A complicating factor of the outbreak is the presence of large numbers of dead, standing, coconut palm trunks, resulting from BCS (Bogia coconut syndrome), which act as breeding sites for the developing larvae. While the impact of beetle feeding can be observed in some pockets, damage is less than expected. OrNV is naturally widespread among CRB-S in the zone which may be contributing to limit the impact of the pest.