Ivy Gourd

Biological Control Section Project, FY 2006:

Ivy Gourd [Coccinia grandis (L.) Voigt].  Propagation of the ivy gourd gall weevil, Acythopeus burkhartorum O’Brien, was terminated at the end of September 2005. The final two releases, consisting of 20 and 126 adults, were made on September 26 & 27, respectively, in Waimanalo along Kalanianaole Highway near Sea Life Park.

Propagation and establishment of this ivy gourd biocontrol agent has experienced difficulties because of its long life cycle, need for shady conditions, and probable field predation by ants and birds.  Establishment had been spotty and, despite limited success at some sites, may now be in doubt.  Fortunately, the ivy gourd vine borer and ivy gourd leafmining weevil are well established and widespread on Oahu, as well as in Kailua-Kona on the Big Island. They are having significant impacts in suppressing ivy gourd population densities. Ivy gourd is now commonly observed only in localities, such as Waimanalo, Kahuku, and Waialua on Oahu, where the microclimate is most favorable for its proliferation. It is very rarely seen in drier localities on the leeward side of Oahu, such as on the slopes of Punchbowl Crater, where it was once the dominant vegetation, shrouding all of the other plants, including many invasive weeds.