Electron-beam irradiation as a quarantine treatment against red mite on exported cut flower of Chrysanthemum

Abstract

Utilization of phytosanitary irradiation as a potential treatment to disinfest agricultural commodities in trade has expanded rapidly in the recent years. In this study, red mites (Tetranychus sp) isolated from cut Chrysanthemums were treated by electron beam irradiation at doses of 100, 200, 300 and 400 Gy. After irradiation, they were kept at room temperature to determine the effects of electron beam irradiation on red mite at different developmental stages (eggs, nymphs and adults) and the reproduction of female adults. The results showed that the pattern of tolerance to irradiation in red mite was eggs < 2nd instars < adults, in which the adults were the most tolerance stage. The number of eggs laid by the irradiated female mites and the hatching rate significantly decreased when the irradiation dose increased. The hatching rate of eggs at 300 Gy was 4.25% and no larvae F1 survived during observation time. It could be concluded that 300 Gy is the effective quarantine dose for red mite infesting on cut chrysanthemums.