Phytosanitary potential of ethanedinitrile: A fungicidal solution for wood pathogens in logs and timber traded internationally

Abstract

Background: Phytosanitary treatments are essential in ensuring the safe trade of logs, lumber, or wood-based products by preventing the spread of harmful insects and pathogens across international borders. Methyl bromide and sulfuryl fluoride are effective fumigants which kill both invertebrate pests and plant pathogens which can damage exported logs. Both have adverse effects on the environment; therefore, less damaging alternatives should be investigated. Ethanedinitrile (EDN) has demonstrated efficacy against invertebrate pests in logs and does not damage the ozone layer or act as a greenhouse gas. However, its efficacy against plant pathogens has not been well tested.

 Methods: This study tested the efficacy of EDN as a fumigant against 20 fungi and oomycetes associated with wood products, such as Pinus radiata D. Don logs. EDN was used as a fumigant in experimental chambers in which Petri plates were inoculated with a 5-mm agar disc from the growing edge of fungal and oomycete cultures. After treatment, mycelial growth was measured every 2–3 days for 14 days, after which EDN-treated discs were transferred to fresh media and growth was observed for an additional 14 days.

 Results: Mycelial growth of all isolates was almost completely inhibited following EDN treatment at 50 g m^-3 for 24 h, with no resumption of growth observed after transferring treated agar discs onto fresh media. The fungicidal effect of EDN was evident in both mycelium and putative survival structures, including oospores and chlamydospores.

 Conclusions: These findings align with those of previous studies highlighting the potential of EDN as an alternative fumigant, offering broad-spectrum efficacy without the environmental drawbacks associated with methyl bromide and sulfuryl fluoride. The results suggest that EDN is an effective phytosanitary treatment for fungi and oomycetes that grow in logs, and that it could be used for managing pathogens associated with P. radiata logs or timber traded internationally. This research contributes to ongoing efforts to improve biosecurity measures in international wood trade.