Phosphine as a possible alternative to methyl bromide for the phytosanitary treatment of wood products

Abstract

Phosphine (PH3) has gained momentum as a phytosanitary treatment to control quarantine pests in exported wood products. Originally used as a grain fumigant, its use increased after methyl bromide was banned for its ozone-depleting properties. While the effectiveness of PH3 against grain pests is well-established, its efficacy for wood products requires review due to growing adoption. We observed insufficient evidence supporting PH3 as a broad-spectrum quarantine treatment for wood products from peer-reviewed/gray literature and international groups. We assessed 41 research articles covering 29 insect species, 1 nematode, and 11 fungi, and observed that while PH3 is effective against some forest insects, it generally fails to meet quarantine treatment standards and is ineffective against nematodes and fungi. Our analysis highlights concerns over the effectiveness of PH3 as a broad-spectrum treatment for wood products. Many studies lack the quality needed to meet contemporary standards. We strongly recommend that National Plant Protection Organizations review the efficacy data supporting PH3 use for wood products to strengthen biosecurity systems.