Oak wilt fungus (Bretziella fagacearum) survival in logs following fumigation with ethanedinitrile

Abstract

The phaseout of methyl bromide (MB) fumigation creates an urgent need for an alternative phytosanitary treatment tolimit the risk of international spread of the oak wilt fungus, Bretziella fagacearum. Fumigation with ethanedinitrile (EDN) isconsidered a potential alternative to MB fumigation to eradicate wood-inhabiting pests and pathogens. We evaluated theefficacy of EDN fumigation by comparing the rate of B. fagacearum isolation before and after fumigation of red oak(Quercus rubra or Quercus ellipsoidalis) log sections from oak wilt–affected trees. Logs (range 15.2 to 98.0 cm long;diameter 9.1 to 46.1 cm) were obtained from red oak trees that were naturally infected (NI) or artificially inoculated (AI) withB. fagacearum. The logs were fumigated for 24, 48, and/or 72 hours with 120 g/m³ EDN. Frequencies of pathogen isolationfrom the sapwood before treatment were higher for AI logs than for NI logs. EDN treatments greatly reduced the frequency ofviable pathogen recovery, but eradication occurred only in experiments using the smallest log diameters (9 to 14 cm). Ourresults suggest that EDN may have limited penetration in oak logs with intact bark, similar to fumigants currently used onwood products, such as MB and sulfuryl fluoride. Results of future work may help in the understanding of the limitations forconsistent and full efficacy of EDN against B. fagacearum in logs harvested from diseased trees.

Citation

Yang, Anna; Seabright, Kendhl; Garrison, Theresa; Taylor, Adam; Myers, Scott; Juzwik, Jennifer. 2023. Oak wilt fungus (Bretziella fagacearum) survival in logs following fumigation with ethanedinitrile. Forest Products Journal. 73(3): 260-266.