Douglas fir and southern pine timbers, 15.2 x 15.2 x 426 cm³ (6-in x 6-in x 14-ft), were "inoculated" with brown-rot and white-rot fungi as vapor-sensing agents to evaluate the movement and distribution of fungitoxic concentrations of chloropicrin, Vapam, and methylisothiocyanate (MIT) over a 20-week period. Residual fumigant in timbers was determined by a bioassay with Gloeophyllum trabeum. The fumigants were introduced into 2.54 cm (1-in) holes at midlength in the timbers. Fumigants diffused throughout the cross-sectional area of both pine and Douglas fir. The brown- and white-rot fungi generally showed similar tolerance to the fumigants. Chloropicrin killed most fungal cultures 0.30 m (1 ft) from the treatment center within 1 week after treatment. Vapam and MIT were effective at 0.30 m by 4 weeks. During the 20-week period, kill of cultures at 0.61 m (2 ft) was quite variable by all fumigants, and almost all cultures 1.22 m (4 ft) from the treatment center survived. Bioassay of cores removed from Vapam-treated timbers showed little residual fungistatic effect beyond 0.30 m. Residual fungistatic effect was detected in MIT- and chloropicrin-treated pine and Douglas fir timbers at 0.61 m.

Download document (513 kb)
free for the members of IRG. Available if purchased.

Purchase this document