Laboratory Evaluations of Wood Preservatives. IV. Effect of Experimental Variables in Testing Creosotes Against Decay Fungi

Costa, E. W. B. Da; Osborne, Lynette D.

doi:10.1515/hfsg.1969.23.6.206

Cited by 4 publications

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“…The brown coal tar creosote proved quite effective against subterranean termites, as it had against decay fungi (Da Costa and Osborne 1969) and this type of material appears to have some potential for use in wood preservation. The brown coal tar creosote proved quite effective against subterranean termites, as it had against decay fungi (Da Costa and Osborne 1969) and this type of material appears to have some potential for use in wood preservation.…”

Section: Discussionmentioning

confidence: 96%

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Laboratory Evaluations of Wood Preservatives. V. The Effectiveness of Some Australian Creosotes against Subterranean Termites

Costa¹,

Gay²,

Osborne³

1971

Holzforschung

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Tests using small standardized laboratory colonies of Coptotermes lacteus, C. acinaciformis and Nasutitermes exitiosus were made on 3 / 4 in. cubes of Pinus radiata D. Don sapwood which had been impregnated with various creosotes and given a modified ASTM laboratory weathering. A vertical retort coal tar creosote in which the phenolic content had been chemically depleted to 8.2% gave much poorer protection from termite attack than a vertical retort creosote with 18.6% phenolic content, whilst a brown coal tar creosote with 24.6% phenolic content was usually intermediate in effectiveness. Addition of 3 % by weight of pentachlorophenol to the low-phenol creosote substantially improved its performance. None of the preservatives tested caused increased mortality of the termites in this "compulsion" test as compared with unfed controls, even at high retentions where the creosoted specimens were almost completely free from attack. It is concluded that with vertical retort creosotes, which could be expected to give protection in service against termites for over 30 years, protection is given by a deterrent and/or repellent mechanism, rather than by a termiticidal effect. Schlüsselwörter (Sachgebiete) Schutzmittelprüfung Vertikalretortenkreosot Phenolgehalt Pentachlorphenol Bodentermiten Coptotermes acinaciformis Coptotermes lacteus Nasutitermes exitiosus Labormäßige Prüfung von Holzschutzmitteln V. Die Wirksamkeit von einigen australischen Kreosoten gegen Bodentermiten Zusammenfassung Es wurden labormäßige Versuche mit kleinen, standardisierten Kolonien von Coptotermes lacteus, C. acinaciformis und Nasutitennes exitiosus durchgeführt, wobei 3 / 4 Zoll (19 cm) große Pinus radiata D. Don-Splintholzklötze mit Kreosot imprägniert und einem modifizierten ASTM Labor-Bewitterungstest ausgesetzt wurden. Vertikalretortenteeröl mit einem chemisch auf 8,2% herabgesetzten Phenolgehalt ergab einen geringeren Schutz gegen Termitenangriffe als ein Vertikalretortenöl mit 18,6% Phenolgehalt, während ein 24,6% phenolhaltiges Braunkohlenteeröl gewöhnlich mittlere Wirksamkeit besitzt. Zugabe von 3 % Pentachlorphenol verbesserte die Wirkung des Kreosotes mit niedrigem Phenolgehalt wesentlich.Keines der untersuchten Schutzmittel dieses "Zwangstestes" hat die Termitenmortalität erhöht im Vergleich zu nicht gefütterten Kontrollgruppen, nicht einmal im Falle von starker Retention, wo die kreosotbehandelten Proben fast gänzlich frei von Termitenangriffen waren. Bei Anwendung von Vertikalretortenkreosot, das in der Praxis über 30 Jahre Termitenfestigkeit gewährt, ist es anzunehmen, daß der Schutz eher durch einen termitenwidrigen und termitenabschreckenden Mechanismus als durch den termitentötenden Effekt hervorgerufen wird. SummaryPeriodically reloading of bending pine wood samples to obtain initial stresses brings about the resistance to relaxation which, however, increases only up to a definite amount of strain. Overrunning this limit of strain means the decrease of resistance to relaxation and ultimately the failure of wood. Strain accumulati...

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Section: Discussionmentioning

confidence: 96%

“…Advantage was also taken of these tests to determine the effectiveness against termites of another type of high phenolic content creosote, namely a creosote produced from brown coal tar, which had given promising results in tests against a number of decay fungi (Da Costa and Osborne 1969).…”

Section: Introductionmentioning

confidence: 99%