Effect of ultraviolet-C radiation on “Kumagai” guavas infested by Ceratitis capitata (Diptera-Tephritidae) and on physical parameters of postharvest

- We evaluate UV-C radiation to disinfest guava fruits from fruit flies.
- We determine the UV-C doses to avoid fruit fly pupation.
- We determine the UV-C doses to prevent fruit fly adult emergence.
- New quarantine treatment by using UV-C radiation is available.
- Disinfestation of guavas fruits for exportation.

Physical quarantine methods are being developed to replace fumigants to control arthropods and microorganisms during post-harvest management of fruit and vegetables. This study aims to evaluate the use of UV-C radiation to disinfest guava with Ceratitis capitata (Wied.) eggs and evaluate the quality of fruit irradiated at two different storage temperatures. For the in vitro test, one-day old C. capitata eggs were exposed to increasing doses of UV-C radiation and stored in a B.O.D. chamber. Applying in vivo tests, 'Kumagai' guavas were exposed to artificial infestation by medfly. After infestation, the fruits were subjected to an increasing intensity of UV-C radiation and stored in a B.O.D. incubator at 23.0 ± 0.2 °C for about 20 days. In vitro tests indicated that 1.383 kJ m−2 UV-C on C. capitata eggs was capable of preventing the eclosion of larvae. However, guavas infested by medfly eggs needed 16.0 kJ m−2 of UV-C to prevent pupation. The guavas subjected to treatment with UV-C radiation and stored at a temperature of 8 ± 0.2 °C, obtained much better responses in terms of quality indices than those stored at 22 ± 0.2 °C, which lends credence to the storage temperature being a key factor in maintaining fruit quality.