A NONTOXIC METHOD TO COMBAT INCIPIENT DECAY OF CCA-TREATED AND CREOSOTE-TREATED POLES IN SOIL-CONTACT

A non-chemical means of preventing premature pole failure in soil-contact was investigated by applying open-ended cylindrical sleeves of heat-shrink polyethylene to the soil-contact surfaces of Eucalyptus grandis poles as physical barriers to fungal colonisation from soil in sub-tropical South Africa. The test site was managed under flood-irrigation to represent vineyard conditions. After exposure for 26 weeks all untreated unsleeved poles had failed, whereas sleeved poles were colonised by fungi but remained relatively sound. Unsleeved poles treated with 16 kg CCA m-3 were colonised by fungi at their soil-contact surfaces, whereas their sleeved counterparts were uncolonised. Unsleeved poles treated with 100 kg creosote m-3 were extensively covered by biofilm and showed incipient decay at their soil-contact surfaces, whereas their sleeved counterparts were uncolonised.