Oryctes rhinoceros nudivirus

The virus was discovered by Alois Huger in 1963 while searching for diseases of O. rhinoceros in Malaysia.

The Oryctes rhinoceros nudivirus develops in the nuclei of infected cells, where the rod-shaped capsids are assembled to a size of 180 x 65 nm.

Virus infections are, however, not transmitted to the pupal stage and adult beetles emerging from the pupae are always uninfected.

[9] Further studies on the Oryctes rhinoceros nudivirus and other non-occluded baculoviruses led to the conclusion that they are significantly different from other members of the family Baculoviridae.

Therefore, in 2012/2013, the creation of a new family, the Nudiviridae, was proposed with several new genera replacing the genus Nudivirus.

[4] The Oryctes rhinoceros nudivirus has been found to be naturally present in Malaysia, Indonesia, the Philippines and India.

[11][12][13] Releases of the virus into virus-free islands resulted in a significant reduction of the beetle population.

[18][13] In the Maldives, such a conversion showed that the introduction of the virus often reduced the number of O. rhinoceros adults attacking coconut palms to less than one quarter of the level before the release.

This is reflected in a natural low level of virus infections in some populations (e.g. South Sulawesi and Java in Indonesia), combined with a high level of palm damage,[19][13] as well as high resistance to artificial virus inoculations in the invasive O. rhinoceros population in Guam.

Under such conditions it is advisable to hide the decaying coconut or oil palm trunks by planting cover crops around them.

Cover crops not only hide the decaying palm trunks from the beetle, they also have a repellent effect on O.

[23] In addition, the spread of the virus can be promoted by leaving a few dead standing coconut palms in the replanted area.

Dead standing coconut palms are the most preferred breeding places, there is frequent contact between adult beetles and larvae in dead standing palms and they are hot spots for virus transmission.

Genome map of Oryctes rhinoceros nudivirus (click on image to enlarge it)
Effect of the introduction of the Oryctes rhinoceros nudivirus on the populations of Oryctes rhinoceros in the Maldives over 4 years. The damage on marked coconut palms has been converted into estimates of number of monthly O. rhinoceros attacks per hectare. Data from islands of Hukurudhoo Atoll (no virus release) are shown as blue dots, those from islands of Ari Atoll (virus released) as brown dots.
Disruption of the transmission of the Oryctes rhinoceros nudivirus during Oryctes rhinoceros outbreaks. The O. rhinoceros population is illustrated by 6 adult beetles, 2 of them infected with the virus. During replanting of a coconut plantation, many potential breeding places become available to O. rhinoceros and contact and virus transmission among adult beetles and between adults and larvae is reduced, resulting in an outbreak situation (upper part). The outbreak can be avoided/reduced by hiding the felled coconut trunks under covercrop and promoting the spread of the virus by a few dead standing palms per hectare (lower part).