A field trial of pigment-emulsified creosote: 11 year data

A field trial was installed to compare the in-ground performance of three r etentions of each of two oilborne preservative formulations: 1) conventiona l high-temperature creosote (HTC); and 2) a modified creosote formulation, pigment-emulsified creosote (PEC). Nominal retentions targeted for each for mulation were 50, 100, and 200 kg/m(3) (3.1, 6.3, and 12.6 pcf). Also inclu ded in the field trial were specimens treated to 308 kg/m(3) of PEC emulsio n to yield an equivalent retention of 200 kg/m3 HTC. Treated and untreated Eucalyptus regnans sapwood specimens were exposed horizontally belowground to a range of economically important species of subterranean termites and w ood-rotting fungi at three test sites in Australia. After 1 1 years of expo sure, E. regnans specimens treated with 200 kg/m(3) of HTC and specimens tr eated with PEC containing 200 kg/m3 of creosote continue to perform well. R esults obtained from the field trial indicate that PEC will perform as well as HTC on an equivalent creosote retention basis. Test specimens were freq uently encountered by the target species of termites (Mastotermes darwinien sis and Coptotermes acinaciformis). In addition, other termite species of l esser economic importance were often observed attacking the softened, funga l-infected surfaces of some of the treated test specimens. Soft rot was the dominant rot type present on treated specimens recorded with fungal degrad e.