In vitro Evaluation of Wood Preservatives to Prevent Dispersal of Pitch Canker Pathogen, Fusarium circinatum

Fusarium circinatum, the causal agent of pitch canker disease on pines, can be disseminated by wood produced in infested areas. The purpose of the study was to evaluate the effect of wood preservatives, commonly used against sapstain and wood-decay fungi, on growth and sporulation of Fusarium circinatum. Seven active ingredients of antisapstain and anti-wood-decay preservatives were evaluated by their inhibition of mycelial growth. Propiconazole, tebuconazole, and 3-iodo-2-propinyl butyl carbamate (IPBC) were effective against F. circinatum, whereas hydroxycarbonate of cooper was not. An assay was also conducted to evaluate the efficacy of three commercial antisapstain and two anti-wood-decay preservatives on Pinus radiata sapwood blocks that were previously inoculated with Fusarium circinatum. The product with the best efficacy was an antidecay preservative composed of tebuconazole, propiconazole, and dichlofluanid. None of the antisapstain preservatives tested was effective even though they contained fungicidal ingredients. Effects of dosage, product application, and formulation on the efficacy of these preservatives are discussed.