GAMMA-IRRADIATION AS A DISINFESTATION AND QUARANTINE TREATMENT FOR FABA BEAN-SEEDS INFESTED WITH BRUCHUS DENTIPES BAUDI (COL, BRUCHIDAE)

A study was conducted to investigate the effectiveness of gamma irradi ation as a disinfestation and quarantine treatment for faba bean seeds which contain larvae and pupae of the faba bean seed beetle, Bruchus dentipes Baudi. The results showed that a dose of 90 Gy applied to the larval stage caused 100% mortality of the treated larvae regardless o f their age or instar. A dose of 300 Gy applied to the late pupal stag e caused 93.8% mortality and rendered the emerged adults unable to fly . In subsequent confirmatory trials in which 100 000 infested seeds we re treated, no adults emerged, which assures quarantine security to pr obit 9 at the 95% confidence level. Our studies indicate that ionising radiation could be an alternative to chemical fumigants for disinfest ation and/or quarantine treatment of faba bean seeds infested with B. dentipes. A dose of 90 Gy applied to faba bean seeds when the pest pop ulation is still in the larval stage, during the first 3 months after harvest, is suggested. To minimise losses in seed quality, however, ir radiation treatment should be done as early as possible after harvest.