Effectiveness of copper chrome arsenate and used engine oil in protecting fencing posts of Ugandan grown eucalypt clone GC550 and Phoenix reclinata against termite attack

P Mugabi,E Otuko

doi:10.4067/s0718-221x2019005000109

Abstract

Eucalypts and Phoenix reclinata posts are the most commonly used species for fencing posts in urban areas of Uganda. Although eucalypts are known to be susceptible to termites, fencing posts are still used untreated. In this study, the effectiveness of Copper Chrome Arsenate and used engine oil in protecting Ugandan grown Eucalyptus grandis × Eucalyptus camaldulensis clone and Phoenix reclinata fencing posts against termite attack were assessed. The objectives were to determine (i) the incidence and (ii) severity of termite attack on Eucalyptus grandis × Eucalyptus camaldulensis and Phoenix reclinata fencing posts treated with Copper Chrome Arsenate or used engine oil. Ninety 2ft long samples of Eucalyptus grandis × Eucalyptus camaldulensis and P. reclinata posts were treated with Copper Chrome Arsenate or used engine and others left to act as control then buried in 1ft deep pits in the ground at a spacing of 1m by 1 in Eastern Uganda. The samples were visually inspected monthly for termite damage for 9 months. More than 80% of untreated samples of both species had been attacked by termites within the first month. Copper Chrome Arsenate treated Eucalyptus grandis × Eucalyptus camaldulensis and Phoenix reclinata samples were first attacked in the 8th and 5th months respectively. While used engine oil treated Eucalyptus grandis × Eucalyptus camaldulensis and Phoenix reclinata samples were first attacked in the 7thand 5th months respectively. The modal severity for samples of both species treated with either Copper Chrome Arsenate or used engine oil was class 1 (less than 1% of the sample volume eaten) while for the untreated samples it was class 5 (above 60% volume eaten) for the 9 months of field exposure. It was concluded that untreated posts of Eucalyptus grandis × Eucalyptus camaldulensis and Phoenix reclinata were highly susceptible to termite attack and that the protection offered by used engine oil or Copper Chrome Arsenate managed to restrict damage by termites to only less than 1% of the sample volume , over the 9 months of exposure for most of the sample posts. It is recommended that the experiment be repeated for a much longer period in order to ascertain the exact service life of the posts under these circumstances. Penetration and retentions of the preservatives in the posts should also be studied in order to ascertain their effect on the efficacy. Keywords: Incidence, severity, treated posts, wood preservation, wood protection

Highlights

The need to improve quality of timber as well as shorten the rotation of trees has led to the development of a number of fast growing forest plantation timber species (Petit and Montagnini, 2004)
Attack on Copper Chrome Arsenate (CCA) treated P. reclinata samples commenced in the 5th month and by the end of the experiment 20% of the samples had been attacked (Figure 2).The first engine oil treated GC550 sample was attacked in the 7thmonth, with only 1 sample attacked by the end of the 9th month
Similar to CCA, engine oil treated P. reclinata samples were first attacked in the 5th month but 40% of these were attacked by the end of the experiment (Figure 2)

Summary

Introduction

The need to improve quality of timber as well as shorten the rotation of trees has led to the development of a number of fast growing forest plantation timber species (Petit and Montagnini, 2004). Fast growing clonal eucalypts were introduced in Uganda from South Africa in 2002 by the National Forestry Resources Research Institute (NaFORRI) (Epila-Otara 2004). GC550, a hybrid of Eucalyptus grandis × camaldulensis is one of the of 12 eucalypt clones introduced in Uganda Because of the relatively high cost of the eucalypt clones, Phoenix reclinata has been used as an alternative to the eucalypts for fencing posts, especially in Central Uganda despite being a palm (Ssembajjwe et al 2005). P. reclinata is a widely planted ornamental palm tree in tropical and subtropical regions. Untreated P. reclinata fencing posts continue to be used in central Uganda

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