Some studies on the chemical control of Dawson gum or blackbutt (Eucalyptus cambageana). Part III. Basal bark and cut stump treatment of multi-stemmed regrowth

Abstract

Results of experiments on the control of Eucalyptus cambageana regrowth, 4-6 m high, by basal bark and cut stump treatments are discussed. Basal bark spraying using Tordon 255 (picloram isooctyl ester 10% + 2,4,5-T propylene glycol ethyl ester 40%) at concns. as low as 0.1% + 0.4% a.i. in oil resulted in kills >84% following treatments in Aug. 1968 and Dec. 1969 when the soil was moist. Under similar conditions, Farmco T80 (2,4,5-T butyl and isobutyl esters 80%) at concns. of 2% a.i. in oil was slightly inferior. Both products were less effective under dry conditions. Cut stump treatments using 0.1% picloram + 0.4% 2,4,5-T both as esters in oil and amines in water resulted in kills in excess of 88% when applied under good soil moisture conditions, whereas 2,4,5-T formulated as esters at 1% and amines at 1 and 2% gave significantly poorer results. All treatments made when the soil was dry produced unsatisfactory results. While a trend towards decreasing effectiveness with increasing stem size was noted, particularly with basal bark treatments, this appeared to have little influence on the overall results. From summary. See WA 26, 1652.