Effect of fumigant dose timber moisture content endgrain sealing and chamber load factor on sorption by sawn timber fumigated with ethanedinitrile

Abstract

Ethanedinitrile (EDN syn cyanogen EDN Fumigas) is a relatively new fumigant with the potential to disinfest quarantine pests from radiata pine (Pinus radiata D Don) logs and sawn timber for export This research evaluated the effects of dose (20 g/m3 or 50 g/m3) timber moisture content (green or kiln dried sawn timber) endgrain sealing (sealed or unsealed timber endgrain) and load factor (11 or 44) on sorption of EDN fumigation chambers Chamber loading significantly influenced sorption with higher loading resulting in greater sorption Changes in the dose of EDN did not affect the sorption pattern Increased moisture content and endgrain sealing both reduced sorption but these effects were relatively small and the differences in sorption patterns caused by moisture content or endgrain sealing decreased over time

Sorption and desorption characteristics of methyl bromide during and after fumigation of pine (Pinus radiata D. Don) logs

“…The rate of sorption was shown to be directly linked to the dose applied. A similar response was shown for sorption of EDN when used to treat pine logs, 11,16 indicating that sorption of these fumigants by pine logs is directly related to the dose applied. As the relative magnitude of this response is consistent across different doses, it can be predicted with a high degree of confidence.…”

“…Other studies have also shown that the rate of sorption is proportionally reduced by the amount of surface area that is sealed. 11,16 Ren et al 13 did not report different sorption rates for MB by the end-and cross-grains of dry timber. However, we showed here a higher rate of sorption through the end-grain of recently harvested logs than through the cross-grain within the first 30 min (Table 3), although this effect was diminished over the fumigation period.…”

“…The factors were chosen either because they represent important variables in commercial fumigations or because they are known to influence the sorption of fumigants significantly. 11,13,16 Each treatment was replicated 3 times, with an average load factor of 46.4 ± 1.5%. Load factor was calculated by measuring the volume of log sections relative to the chamber volume.…”

“…Sorption rates vary with the fumigant used, the material being treated and the load factor. 11 Higher rates of sorption are generally undesirable because less of the applied fumigant is available in the treated space for respiratory uptake by insects. 12 Ren et al 13 compared sorption rates of MB, sulfuryl fluoride, ethanedinitrile (EDN) and phosphine (PH 3 ) in Douglas fir [Pseudotsuga menziesii (Mirb.)…”

Influence of dose bark cover and endgrain sealing on ethanedinitrile (C₂N₂) sorption by pine (<i>Pinus radiata</i> D Don) logs

“…Fumigant sorption refers to the removal of fumigant from the headspace by the substrate being treated. Sorption rates vary with the fumigant used, the substrate being treated and the load factor (Pranamornkith et al 2014a). High rates of sorption are generally undesirable because less of the applied fumigant is available in the headspace to control the target insects (Lorraine 2014).…”