LAUSR

BACKGROUND Ethanedinitrile (EDN™) is a fumigant being commercialised worldwide as an alternative phytosanitary treatment to methyl bromide (MB) for forest products. The penetration characteristics of MB and EDN were measured through the bark of wooden blocks (100 × 100 × 50 mm) cut from the upper (average bark thickness 5 ± 2 mm) and lower (average bark thickness 25 ± 5 mm) trunk of recently felled pine (Pinus radiata D.Don) trees. Doses of 48 g m-3 MB and 50 g m-3 EDN were applied to chambers at 10 and 20 °C for 10 h. RESULTS The penetration of MB was influenced by the interaction between the fumigation time and temperature, with concentrations increasing at a higher rate at 20 °C when compared to 10 °C. After 10 h, an average concentration of 8.05 ± 0.89 g m-3 had penetrated the bark of log sections at 20 °C, while 5.20 ± 0.89 g m-3 was measured at 10 °C. In contrast, the factors examined in this study did not significantly impact the penetration of EDN. Concentration x time (CT) values for MB under the bark were 35.20 ± 2.30 g h m-3 at 10 °C and 55.85 ± 9.58 g h m-3 at 20 °C; while for EDN, CT values were 19.50 ± 6.80 g h m-3 and 19.08 ± 4.10 g h m-3 at respective temperatures. CONCLUSION MB can achieve a higher concentration under the bark of log sections during simulated fumigations, but all of the factors examined affected MB's ability to penetrate the bark of wooden blocks. In comparison, the penetration of EDN through the bark is more consistent than MB under laboratory conditions.