The Economic Importance of the Fruit Fly, Dacus zonatus (Saunders) in Thailand

Abstract

Egg, larval, pupal and adult stages of the fruit fly, Dacus zonatus (Saunders), lasted on the averages 33.13 hours, and 7.40,11.00 and 71.00 days respectively when reared on a semiartificial diet which consisted of banana pulp, corn flour, Brewer's yeast, sugar, tissue paper, sodium benzoate, hydrochloric acid, and water. They were comparatively close to the oriental fruit fly, Dacus dorsalis Hendel, which lasted on the averages 36.13 hours, and 8.20, 11.50 and 88.40 days respectively when reared on the same diet. Riped fits sampling from trees of Singapore almond (Terminalia catappa Linn.), ma-kok-nam (Elaeocapus madopetalus Pierre), guava (Psidium guajava Linn.), and rose apple (Eugenia javanica Lamk.) in Bangkok area in july, August, December, and February showed the infestation of D. zonatus in association with D. dorsalis. Th'e ratios of adult flies of D. zonatus and D. dorsalis emerged from these fruits were 1 : 1.09, 1 : 0.07,l : 2.88 and I : 1.33 respectively. With its wide range of host and distribution, D. zonatus has become one of the major economic important pests of fruits, comparable to D. dorsalis, in this country.