Effects of Thai Plant Extracts on the Oriental Fruit Fly II. Repellency Test.

Abstract

The repellent potency of plant extracts to the Oriental fruit fly, Dacus dorsalis, was determined on the basis of the rate of oviposition on cups containing 20% of citrus juice and coated outside with a mist spray of one gram equivalent of each plant extract per cup. One hundred and thirty extracts from 110 kinds of plants among which 97 were known species and 13 unknown were tested. Fifteen day old female flies which were known to lay high numbers of eggs were used in this experiment. Plant extracts which exhibited high repellency to the oviposition of the female flies were obtained from Azadirachta indica var. siamensis Veleton, Bixa orellana Linn., Citrus hystrix D.C., Cucumis melo Linn., Cymbopogon citrates Stapf., Hedychium coccineum var. angustifolium Roxb., Heliotropium indicum R. Br., Homalomena sp., Ocimum gratissimum Linn., Ricinus communis Linn., and Ternstroemia japonica Thunb. Among the unidentified species, they included En-Luang and Phra-Taba. Moderate levels of repellency were obtained from extracts of Allium sativum Linn., Melodorum fruticosum Lour, and Meha-Kamlang. Mild repellent to the oviposition of the flies was exhibited by plant part extracts of the following species: Acharas aspota Linn., Alpinia siamensis Schum., Andrographis paniculate Wall. Ex Nees, Anona squamosa Linn., Anthemis nobilis Linn, Bougainvillea spectabilis Willd., Cinnamomum siamense Craib., Cinnamomum zeylanicum Linn., Curcuma comosa Roxb., Curcuma longa Linn. ( = C. domestica Veleton), Curcuma zedoaria Roxae, Elholtzia blanda Benth., Eupatorium adenophorum Spreng., Jatropha curcas Linn., Jatropha gossypifolia Linn., Litsea cubeba Pers., Mentha cordifolia Opiz., Momordica charantia Linn., Myristica fragrans Linn., Piper sarmentosum R. ex H., Portulaca pilosa Linn., Quisqualis indica Linn., Stemona tuberose Lour., and Tinospora crispa Miers. Of the unidentified species, they included Gai-Khan, Kan-Tha-Mala, Lai-Ma, Ma-Haw, and Maurakot.