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Validating a short-term laboratory method to assess the resistance of timber to biodegradation by marine wood-borers
2021 - IRG/WP 21-10975
Novel approaches to protecting wood in coastal and marine environments are needed as the use of traditional broad-spectrum biocides are now restricted. Wood is widely utilised in marine environments where it can be rapidly degraded by wood-boring organisms, causing billions of dollars of damage per annum. Biocidal compounds such as CCA and creosote have been popular treatments for timber products during the last century but have since been restricted or banned in several countries, including the UK. Novel methods in wood modification and protection are therefore required to replace such techniques. Use of lesser-utilised timber species and wood modification offers a promising alternative approach of reducing damage by marine wood-borers. Processes of modification are evolving rapidly, so long-term testing needs to be supplemented by rapid testing methods in order to speed up process development. New potential products must undergo thorough testing in order to be commercially viable and to minimise environmental impacts. Marine trials require long exposure periods and are thus expensive and slow to yield meaningful results. Laboratory tests, however, provide a much quicker alternative to test novel timber products against gribble attack. A standard method for assessing the feeding rate of the wood-boring crustacean the gribble (Limnoria spp.) can be used to determine if the wood affects feeding rate and mortality. This is investigated through assessing faecal pellet production (used as an indicator of feeding rate), vitality, and mortality rates. These data combined, can begin to identify products that have the potential to be resistant marine wood-borer attack.
L S Martin, J R Shipway, G P Malyon, S M Cragg

Wood modification reduces the feeding rate of the wood boring crustacean, Limnoria quadripunctata
2022 - IRG/WP 22-10993
Adult Adult Limnoria search for new wood once their current piece disintegrates from tunnelling. During this time, they do not have access to wood so experience a period of starvation and must feed again once settled. Wood modification offers protection to marine structures by reducing the feeding rate of Limnoria and therefore can reduce recruitment of adults from distant pieces of wood. Chemical modification, such as furfurylation, protects wood against damage by marine wood-borers, without the use of broad-spectrum biocides which can leach out into the surrounding ecosystem. Preservatives such as CCA have been restricted in the UK, EU, USA and Australia therefore, novel, more environmentally friendly products are required for use in marine environments. In this study, individual Limnoria quadripunctata were fed continuously, starved continuously and starved then re-fed after two weeks on control or furfurylated wood. Two different drying/curing schemes in an experimental furfurylation process were used for modification of Pinus radiata. The treatments, which differed in peak temperature and total process time, resulted in approximately the same weight percentage gain. Treatment 1 with the lower peak temperature and longer process time and treatment 2 with the higher peak temperature and shorter total process time. Treatment 1 resulted in a slightly lower faecal pellet production than treatment 2 from L. quadripunctata that fed continuously and from those that were starved and refed. It was also more likely to cause mortality earlier on in the experiment, possibly due to incomplete polymerisation from the lower curing temperature. Although a long leaching period is required to remove extractives, this lower temperature drying/curing regime seems to be effective at both reducing the feeding rate of healthy adult Limnoria and individuals that have been starved for 14 days. However, treatment 2 also significantly reduced feeding rate compared to untreated wood. Furfurylation is an effective treatment to protect wood against Limnoria attack, although drying/curing temperature and time and leaching time affect feeding rate and mortality. Treated wood is likely to impact animals that experience starvation, although further investigation is required to compare treatments 1 and 2 with changes seen in Limnoria refed control wood.
L S Martin, S Lande, M Westin, S M Cragg

Movement and persistence of Dazomet and pellected methylisothiocyanate in wrapped Douglas fir and southern pine timbers
1991 - IRG/WP 1496
The movement and persistence of Dazomet (tetrahydro-3,5-dimethyl-2 H-1,3,5 thiadiazine-6-thione) and pelleted methylisothiocyanate (MIT) was evaluated in wrapped Douglas-fir and Southern Pine timbers. MIT pellets did not impart a fungistatic effect to any of the timbers. Failure of MIT was probably due to loss of MIT from pellets prior to application. Fungistatic effect of Dazomet was consistently detected at 0.3m from the treatment center but effect beyond this distance was variable. Fungistatic effect was detected at 2 years after Dazomet treatment in Southern Pine but not at 3 years. Fungistatic effect was still present in Douglas-fir timbers at 3 years.
T L Highley

What Can Fecal Pellets Tell Us About Cryptic Drywood Termites (Isoptera: Kalotermitidae)?
2009 - IRG/WP 09-20407
Drywood termites (Isoptera: Kalotermitidae) are serious economic pests of both plants and seasoned wood (furniture, wood frame structures). Currently, five species of kalotermitids are known to occur in the Hawaiian Islands: Neotermes connexus, Incisitermes immigrans, Incisitermes minor, Cryptotermes brevis, and Cryptotermes cynocephalis. These termites are difficult to detect and observe due to their cryptic habitat. Unlike termites that nest in the soil, and forage outward for wood, drywood termites nest directly in their food source. Often, the only outward sign of termite infestation is the presence of small fecal pellets, expelled from the gallery system through small holes in the wood surface. This report reviews recent research indicating that these fecal pellets may be a valuable source of information on the biology of these cryptic insects, including the identity of the termite species, the relative cellulose content of the food source, and the size and even the age of the population.
J K Grace