Fungitoxicity of Methyl Iodide, Sulfuryl Fluoride, and Methyl Bromide to Ceratocystis fagacearum in Red Oak, Maple, Poplar, Birch and Pine Wood ()
ABSTRACT
The threat of wood-inhabiting fungi to American hardwood forests, lumber industries, and tourism has enormous eco-nomic significance, and the aesthetic and dollar values of properties are potentially disastrous. The efficacy of methyl iodide (MeI) and sulfuryl fluoride (SF) for eradicating wood-inhabiting fungus, Ceratocystis fagacearum was assessed in wood blocks of birch, maple, poplar and red pine based on in-vitro experiments. In a series of replicated controlled experiments, wood blocks were inoculated with a 1g macerated mycelium/spores mixture of C. fagacearum and fumigated with 160 and 240 g/m3 of MeI, SF and methyl bromide (MeBr) as control) for 24, 48, and 72 hours. Analysis of variance showed that fumigant types, fumigant concentrations, and exposure time as well as their interactions (C x T) had an effect on C. fagacearum recovery on tested wood species. Colonization of birch, maple, red pine, and poplar by C. fagacearum was significantly greater in non-fumigated samples than fumigated samples. C. fagacearum was greatly inhibited by MeI than SF in all wood species tested. Overall, the C x T products of ≤ 4.108 g-h/m3 for MeI and ≤ 8.755 g-h/m3 for SF were not effective in killing the fungus. These results suggest that longer treatment exposure time might achieve the goal of complete eradication of C. fagacearum and imply that MeI performed as well as MeBr in killing the fungus in some wood species by exposure time combination. Overall, MeI was most effective in killing the fungus than SF under the conditions of this study with potential implications for quarantine use.