Quarantine treatments of imported nursery plants and exported cut flowers by phosphine gas (PH 3 ) as methyl bromide alternative

Quarantine treatments by phosphine (PH3) gas have been performed to replace methyl bromide (MeBr) for export cut flowers and imported nursery plant in Korea. In this preliminary study, two dominant insect pests of cut flowers, Tetranychus urticae Koch and Frankliniella occidentalis Pergande, and the dominant insect pest of nursery plants, Planococcus citri Risso, were used to certify optimum concentration and fumigation time, along with evaluation of phytotoxic damages. To validate the results of preliminary tests, quarantine treatments for export cut flowers was performed in a 58-m(3) reefer container. When 14 species of cut flowers were fumigated with 2g m(-3) PH3 for 24 h (Ct product was 30.9g h m(-3)) at 5 degrees C, all pests were effectively controlled and no phytotoxic damage were observed on roses and chrysanthemums. On quarantine trials for imported nursery trees, which was performed at 10 m(3) scale covered with a PVC-tarpaulin tent, 2 g m(-3) of PH3 for 24 h (Ct product was 30.0g h m(-3)) at 15 degrees C was enough to kill all pests and no damage was observed on seven species of nursery plants. Phosphine gas shows the promise as MeBr alternative to perishable commodities in terms of efficacy to certain quarantine pest and maintenance of its quality as well as being a more environmentally safe fumigant.