Variable susceptibility of common sapstain fungi to commercial antisapstain products

Susceptibility of common sapstaining fungi to antisapstain products was exa mined using a rapid antisapstain laboratory disc trial. The ability of fung al isolates to colonise radiata pine branchwood discs treated with various commercial antisapstain formulations was used as an indicator of fungicidal susceptibility or tolerance. The results of this investigation showed that under laboratory conditions, susceptibility to antisapstain formulations v aried greatly, both between species, and between isolates of the same speci es. None of the formulations gave consistent control of all the isolates wh en tested at commercial usage rates. The significance of these results is d iscussed in terms of design of laboratory antisapstain trials and its poten tial relevance in the field.