POPULATIONS OF BACTROCERA CUCURBITAE (DIPTERA: TEPHRITIDAE) AND ITS PARASITOID, PSYTTALIA FLETCHERI (HYMENOPTERA: BRACONIDAE) IN COCCINIA GRANDIS (DUCURBITACEA) OR IVY GOURD ON HAWAII ISLAND

Authors: Jackson, Charles; Vargas, Roger; SUDA, DAVID - USDA-ARS BASIN RES CTR HI

Submitted to: Hawaiian Entomological Society Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2003
Publication Date: N/A
Citation: N/A

Interpretive Summary: Scarlet-fruited gourd is a climbing vine that can cover trees, fences, power lines, and buildings. It has invaded Hawaii, where it has been declared a noxious weed. Besides being a pest, its fruit serves as a host for the melon fruit fly that is a serious pest of cucurbits and a potential invader of the mainland USA. We sampled scarlet-fruited gourd for two years sto determined its contribution to melon fly populations. We reared 500 - 800 flies from each kilogram of fruit, demonstrating that this weed is an important contributor to melon fly populations. Only 5-6% of the melon flies were parasitized during the two-year study. This weed should be considered in any pest management program to control melon flies.

Technical Abstract: The melon fly, Bactrocera cucurbitae (Coquillett), readily lays eggs and develops in scarlet-fruited gourd, Coccinia grandis (L.). This plant has become naturalized in Hawaii where it is considered a noxious weed. We sampled C. grandis over a two-year period. In 1993 and 1994, average numbers of 500 to more than 800 adult melon flies per Kg of fruit were recovered suggesting that C. grandis is an important contributor to this pest's population. Natural parasitism of melon flies by the introduced braconid wasp, Psyttalia fletcheri (Silvestri), averaged 5.5 % during the two-year study. Less than 1.0% of the fruit was infested by the oriental fruit fly, B. dorsalis (Hendel), and the Mediterranean fruit fly, Ceratitis capitata (Weidemann).