The use of Gamma radiation of Cobalt-60 to control avocado moth Stenoma catenifer Walsingham, 1912 (Lepidoptera: Elachistidae) and its effects on the quality of the fruit of Persea americana (Miller) (Lauraceae)

This work aimed to evaluate the influence of Gamma radiation of Cobalt-60, in the avocado moth Stenoma catenifer Walsingham, 1912 (Lepidoptera: Elachistidae) and its effects on the quality of the fruit Persea americana (Miller) (Lauraceae). For this research, insects were irradiated in ali phases of their life cycle with doses varying from O to 600 Gy and they were maintained at the temperature of 25 +- 2 deg C, humidity of 70 +- 10% and photo phase of 14 h. The species was raised on natural diet, avocado seeds. The cultivar fruits Geada were irradiated with doses that varied from 0 to 150 Gy, maintained for 15 days at room temperature (20 a 35 deg C and humidity of 70 - 80 %) and 30 days at a temperature of 10 deg C, humidity of 40 - 60 %. The chemical-physics and sensorial analyses were carried out. According to the obtained results, it was verified that the lethal dose of gamma radiation to S. catenifer eggs, was of 75 Gy; for caterpillars and pupas was of 300 Gy. The sterile-dose for upcoming adults from irradiated S. catenifer eggs was of 25 Gy; for upcoming adults from irradiated caterpillars, it was of 100 Gy; for adults coming from irradiated pupas was of 150 Gy and for irradiated adults was of 200 Gy. The irradiation in the avocado fruit, maintained at room temperature for 7 days of storage, caused change in the coloration of the fruit (dark spots and yellowish coloration) and more firmness. The sensorial characteristics were kept and the irradiated fruit was the chosen one as favorite for tasting. The irradiated fruits that were kept at 10 deg C, obtained an increase in the storage period, without changing their chemical physics characteristics. The coloration of the fruits was kept, more firmness and a subtle acidity taste increase, being effective in the conservation of the fruits and in the maintenance of their sensorial characteristics. The use of the gamma radiation as treatment quarantine of S. catenifer it was efficient, should be treated them with doses capable to promote the sterilization of the insect, without committing your qualities physical-chemistries and sensorial of the fruits. Therefore, it is suggested the treatment with the dose of 50 Gy for fruits infested with eggs and 150 Gy for fruits infested with caterpillars and pupas of S. catenifer, maintained in temperature of 10 deg C. Para the use of the Technique of the Sterile Insect it is recommended the irradiation of pupas and adults with doses of 150 Gy and 200 Gy, respectively. (author)