Both moulds and bluestain fungi cause serious economic losses for forestry and timber processing industries and much research is aimed at finding environmentally and economically acceptable methods of control. It is especially important to study the growth of these fungi in freshly cut wood, which has been unaltered by drying or sterilisation, and which therefore resembles the substratum they would normally invade under natural field conditions. To meet this objective the growth of six sapstain fungi was compared at 20°C in freshly cut pine billets and on three types of artificial media (MEA, TWA and Pine Sapwood agar). The fungi comprised Ceratocystis coerulescens, Leptographium wingfieldii, Ophiostoma minus, Ophiostoma piceae, Potebniamyces coniferarum and Sphaeropsis sapinea. The six species varied markedly in their linear growth rate on agar media. In pine billets, they extended at different rates in longitudinal, radial and tangential directions, showing different pathogenic ability, patterns of colonisation and capacity to stain wood or kill bark. Some species appeared to be 'xylem preferring' while others appeared to colonise the phloem tissue more readily. Interestingly, the growth of Ceratocystis coerulescens in pine billets was more then two times faster than on MEA, suggesting it was strongly stimulated by the living pine tissue. In addition, there was an indication that the fungi grew more slowly in logs cut in January than in the summer.

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