Screening method to test efficacy of fumigants against fungi and preliminary data on the efficacy of sulfuryl fluoride
A Uzunovic, A Mukherjee, R Mack, P Elder, S Myers
Methyl bromide is being phased out and there is an urgent need to find a suitable replacement that is effective in reducing exotic pest establishments via trade in wood products. Efficacy data for established phytosanitary fumigants were mostly developed for arthropods and nematodes, and limited information exists for plant pathogens. Increased interest in developing a fast screening process for fungi has prompted this work. Small scale sulfuryl flouride fumigations were conducted in 10 L chambers at six target concentrations (40-240 mgL-1) at 20 C for 24 h against 23 fungal species. Fungi were grown on barley/grain, which was placed in borosilicate glass tubes covered on both ends with a felt cloth to allow uninhibited gas penetration while minimizing the risk of fungal contamination. This allowed simultaneous testing of numerous species/isolates followed by 100% recovery of controls and without contamination of all other isolates exposed to six target sulfuryl fluoride concentrations. Preliminary data have shown that 13 out of 23 species survived the 240mgL-1 exposure. Additional research is needed to test efficacy against more isolates, and under different temperatures and exposure times before experiments closer to field conditions are conducted.