Scarlet gourd is a fast growing vine that climbs up trees and kills them over time by taking away available light. It has been known to cause power outages when climbing up telephone poles.
The University of Guam, with help of the U.S. Department of Agriculture, conducted research on biological control of scarlet gourd.
With the support of the Northern Marianas College-Cooperative Research Extension and Education Services, UOG scientists Dr. Rangaswamy Muniappan and Dr. Gadi Reddy in 2003 released on Saipan the scarlet gourd weevil (Acythopeus cocciniae) and in 2007 a moth, the scarlet gourd vine borer (Melittia oedipus).
Both insects are specialized on scarlet gourd, which means they will not attack any other plant species. Once the population of scarlet gourd is reduced, the number of insects will also shrink.
Earlier during the month, Reddy and Muniappan returned to Saipan to study the situation. Together with staff from NMC-CREES, entomologist Dr. Marisol Qunitanilla and retired entomologist Dr. Joaquin Tenorio toured the release sites on Saipan. The research the presence and the status of reproduction of moths and weevils.
The result of all studies and researches have been very positive. Extensive leaf damage on the scarlet gourd showed that the weevil is well established on Saipan. Boreholes on many scarlet gourd stems showed that the moth was also doing well. The scientists were able to find live larvae and pupae of moth and continued research is being done through the NMC-CREES entomology lab for rearing of additional moths.
As a part of his observation, Muniappan concluded that scarlet gourds retreated by about 30-50 percent since the release of the insects.
Muniappan and Reddy are confident that should all factors remain constant and stable that the scarlet gourd will be further reduced over the next couple of years.
