Evaluation of Different Applications of Ethanedinitrile (C2N2) in Various Fumigation Chambers for Control of Monochamus alternatus (Coleoptera: Cerambycidae) in Naturally Infested Logs.

Monochamus alternatus Hopeis is an important vector of nematode pests of timber in Korea, particularly Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle. Previously, we reported that ethanedinitrile (C2N2) has the potential to replace methyl bromide and metam sodium to control M. alternatus larvae and B. xylophilus under low-temperature (<5 °C) conditions. Herein, we report on fumigation trials of C2N2 over a 3-yr period (February 2013-October 2015) conducted at higher temperatures. The trials were conducted under 24 different conditions that incorporated varying fumigation chamber types (plastic sheeting-enclosed chambers of differing construction or an ISO shipping container, interior size: 5.90 m length by 2.35 m width by 2.40 m height), log water content (24.1-43.5%), filling ratios (5, 20, and 40%), and temperatures (10.5-17.3 °C). Highest concentration × time (Ct) product values were obtained with the ISO shipping container followed (in order of decreasing Ct values) by a 0.1-mm-thick, low-density polyethylene tarpaulin enclosure, a 0.1-mm-thick polyvinyl chloride (PVC) tarpaulin enclosure, and a 0.05-mm-thick PVC tarpaulin enclosure. The correlation between Ct product value and mortality of M. alternatus larvae was calculated with all treatment combinations. From this, the L(Ct)50 and L(Ct)99 values for C2N2 were determined to be 73.19 and 194.90 g h m-3, respectively. Ethanedinitrile showed promise as a practical alternative fumigant for use on fresh pine logs infested by M. alternatus larvae.