Irradiation as a Potential Phytosanitary Treatment for the Mango Pulp Weevil Sternochetus frigidus (Fabr.) (Coleoptera: Curculionidae) in Philippine Super Mango
Irradiation was explored as a method of quarantine disinfestation treatment for the mango pulp weevil Sternochetus frigidus (Fabr.). S. frigidus is an important quarantine pest preventing the export of mangoes from the Philippines to countries with strict quarantine regulations. Mangoes obtained from Guimaras Island are exempt from this ban as they are certified to be free from seed weevil and pulp weevil infestation. In the dose-response tests, S. frigidus larvae, pupae and adults in mangoes were irradiated at target doses of 25, 50, 75, 100, 150, 300 and 400 Gy. The number of eggs laid by adult females decreased with increasing dose. Treatment with irradiation doses of >75 Gy resulted in sterility in adults developing from larvae and pupae while doses of >100 Gy resulted in sterility in irradiated adults. The adult was the most tolerant stage based on sterility or prevention of adult reproduction. Significant differences were observed in adult longevity among treatment doses in S. frigidus, but none between sexes and in the interaction between dose and sex.
Key Words: disinfestations, mango pulp weevil, postharvest phytosanitary treatment, quarantine pest, Sternochetus frigidus
Abbreviations: AQIS – Australian Quarantine Inspection Service, DUR – dose uniformity ratio, MPW – mango pulp weevil, PNRI – Philippine Nuclear Research Institute, USDA-APHIS – United States Department of Agriculture - Animal and Plant Health Inspection Service