Experimenting weevil control

Photo: Scot Nelson et. al./University of Hawaii at ManoaYou may have never encountered the New Guinea sugarcane weevil Rhabdoscelus obscures, but this naughty little weevil may be enjoying life in your coconut, betel nut or other palms. The larvae bore into living tissue of palm branches, producing tunnels that weaken affected parts of the host plant and permit the invasion of fungal and bacterial pathogens.

In coconut palms they bore into the base of the trunk and can weaken the tree until it is blown down in high winds. In betel nut palms they frequently bore into areas near the growing tip of the tree and the end result may be death.

Dr. Gadi V. P. Reddy of the Western Pacific Tropical Research Centre, UOG has been awarded a USD75,000 USDA Natural Resources Conservation Service grant to address the weevil threat to palms in the region. This miniature menace is especially troubling for nursery owners.

In collaboration with the Northern Marianas College, Dr. Reddy and his research team will develop environmentally friendly control tactics designed to reduce the use of insecticides currently employed to control the New Guinea sugarcane weevil. This integrated pest management (IPM) approach will safeguard the environment and keep palm trees healthy.

USDA grant funding will support the design of an efficient pheromone trap for catching weevils in field conditions, and experiments with Petri dish traps containing fungal spores (Beauveria bassiana and Metarhizium anisopliae) for auto dissemination through trapped weevils.

Dr. Reddy will conduct sugarcane weevil control experiments at several major ornamental nurseries throughout Guam, which will allow growers and nursery owners to participate in all phases of the project and learn integrated control tactics and environmentally friendly best pest management practices. This project will provide basic, applied, and practical information on the control of R. obscurus in the Mariana Islands.