Pupal Eye Color of Bactrocera philippinensis
(Drew & Hancock) as Tool for Radiation Sterilization

Sotero S. Resilva* and Glenda B. Obra

Agriculture Research Group, Atomic Research Division
Philippine Nuclear Research Institute, Department of Science and Technology
Diliman, Quezon City

corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.



This paper reports on the documented pupal eye color of Philippine fruit fly, Bactrocera philippinensis, at different holding temperatures. In holding mature larval samples at 28 (standard holding temperature), 25, 19 and 15 ºC, the development of pupae were 10, 13, 22 and 37 days, respectively. Holding pupae at lower temperature delays pupal development and slow down progression of daily eye color changes. This is very important in manipulating pupal development especially when uncontrolled problems occur during SIT operations. The recommended timing of pupal irradiation for B. philippinensis at 28 ºC (standard holding temperature) is at two days before adult emergence, where the pupae are 7-day old and the eye color is yellowish brown. Using this eye color as the reference guide for irradiation of pupae, the right age when held at 25, 19 and 15 ºC was 9, 15-16, and 25-28 days old, respectively. Documented and close-up photograph of pupal eye color can be used as a reference guide to determine the best time for the irradiation of pupae in an Sterile Insect Technique (SIT) program.



The Philippine fruit fly, Bactrocera philippinensis (Drew and Handcock) is a very serious pest of most fruit crops, especially mangoes in the Philippines. Fruit fly infestation was reported to have caused premature falling and rotting of mangoes. (Manoto et al 1998). Ovipositional punctures which appears at ripening of fruits also affect the quality of fruit thus losing its market value. They causes major damage in the field and are considered quarantine barrier to fruit exportation.One method of control which does not pollute the environment in controlling insect pest is the Sterile Insect Technique (SIT). It involves mass production of target pest, sterilization with irradiation using an appropriate dosage of gamma rays and release in target areas against their wild counterparts. Continuous releases of sterile insects will eventually eliminate the pest thereby establishing pest-free area. . . . . read more



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