Comparison of Residual Methylisothiocyanate (MITC) in Australian and South American Hardwood and Softwood Treated with a Solid Compressed Dazomet Fumigant Stick

The efficacy of compressed dazomet sticks with or without a copper-based accelerant for control of internal decay of both softwood and hardwood species was examined in multiple field trials. Effective levels of methylisothiocyanate (MITC), the fungitoxic decomposition product of dazomet were found in Australian spotted gum (Corymbia spp) and Guyanese Wallaba (Eperua falcata) as well as in southern pine (Pinus spp.) pole sections exposed (in-ground) for three to five years. Sustained MITC levels above the fungitoxic thresholds were found for all three species indicating that this treatment will fit well within the normal 3-to-5-year inspection cycle used in Australia. Further assessments are underway.