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

Phosphine (PH 3 ) 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 PH 3 against grain pests is well-established, its efficacy for wood products requires review due to growing adoption. We observed insufficient evidence supporting PH 3 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 PH 3 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 PH 3 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 PH 3 use for wood products to strengthen biosecurity systems. • Phosphine has gained momentum as a phytosanitary treatment to control quarantine pests in exported wood products. • We assessed 41 research articles covering 29 insect species, 1 nematode, and 11 fungi. • The scientific evidence to support the efficacy of phosphine has not been offered through peer-reviewed or gray literature. • Future research should determine the most phosphine-tolerant species under small and large-scale scenarios.