Skip to main content
ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Plant Genetic Resources and Disease Research » Research » Publications at this Location » Publication #379080
Research Project: Genetic Improvement and Sustainable Production Systems for Sub-tropical and Tropical Crops in the Pacific Basin

Location: Tropical Plant Genetic Resources and Disease Research

Title: Borate and quaternary ammonia dip diffusion to treat fungal pathogens of Metrosideros polymorpha wood

Author
item HUGHES, MARC - University Of Hawaii
item MORRELL, JEFFREY - University Of Sunshine Coast
item CAPPELLAZZI, JED - Oregon State University
item MACKEY, BRUCE - US Department Of Agriculture (USDA)
item JUZWIK, JENNIFER - Forest Service (FS)
item Keith, Lisa

Submitted to: Forest Products Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2020
Publication Date: 3/31/2021
Citation: Hughes, M.A., Morrell, J.J., Cappellazzi, J., Mackey, B., Juzwik, J., Keith, L.M. 2021. Borate and quaternary ammonia dip diffusion to treat fungal pathogens of Metrosideros polymorpha wood. Forest Products Society. 71(1):20-26. https://doi.org/10.13073/FPJ-D-20-00068.
DOI: https://doi.org/10.13073/FPJ-D-20-00068

Interpretive Summary: Rapid Ohia Death is a major concern for the viability of ohia (Metrosideros polymorpha) in Hawaii and has led to restrictions on log movement. The potential for using sodium octaborate tetrahydrate (DOT) dip diffusion treatments to control the two causal fungi (Ceratocystis lukuohia and C. huliohia) was investigated. While the results show some promise, further investigations are needed to explore using either higher boron concentrations or longer diffusion periods for ability to deliver fungicidal concentrations of boron deeper within the wood matrix.

Technical Abstract: Rapid Ohia Death is a major concern for the viability of ohia (Metrosideros polymorpha) in Hawaii and has led to restrictions on log movement. The potential for using sodium octaborate tetrahydrate (DOT) dip diffusion treatments to control the two causal fungi (Ceratocystis lukuohia and C. huliohia) was investigated. A 10% boric acid equivalent dip diffusion treatment killed the pathogens in 0.5 cm wide disks obtained from 4.0 to 5.0 cm diameter limbs of naturally colonized trees. DOT tended to diffuse more consistently in 50 to 60 cm long bolts of small and large diameter healthy ohia compared to those bolts naturally-infected by C. lukuohia. Diffusion periods longer than 6 weeks resulted in deeper penetration. Logs (1.3 m long; 9 to 17 cm dia) obtained from C. lukuohia artificially-inoculated trees in two forest locations were immersed (24 hr.) in a 15% DOT/1%DDAC solution and then stored for 10 weeks before evaluation. These treatments resulted in incomplete elimination of the pathogen and lower boron concentrations in the inner sapwood than outer. Further investigations are needed to explore using either higher boron concentrations or longer diffusion periods for ability to deliver fungicidal concentrations of boron deeper within the wood matrix.