Tropical Grasslands (1994) Volume 28, 120126
Foliar application of 2,4-D/picloram, imazapyr, metsulfuron, triclopyr/picloram, and dicamba kills individual rubber vine (Cryptostegia grandiflora) plants
J.S. VITELLI1, R.J. MAYER2 and P.L. JEFFREY1
1Department of Lands, Tropical Weeds Research Centre, Charters Towers, Queensland, Australia
As part of a program to develop effective and affordable integrated pest management systems for the control of rubber vine (Cryptostegia grandiflora), 10 foliar-applied herbicides were trialled at various dose rates in north Queensland to determine their effectiveness in controlling scattered rubber vine infestations (< 1000 plants/ha). Five herbicides (2,4-D/picloram (Tordon 50-D) at 1.33/0.33 g/L, imazapyr (Arsenal 250A) at 1.25 g/L; metsulfuron (Brush-Off) at 0.09 g/L; triclopyr/picloram (Grazon DS) at 1.5/0.5 g/L; and dicamba (Banvel 200) at 2.0 g/L) killed 90–100% of the treated plants. The other 5 herbicides (2,4-D ethyl ester (Estercide 800) at 8 g/L (51% kill); 2,4-D butyl ester (AF Rubber Vine Spray) at 2.0 g/L (49%); glyphosate (Glyphosate 360) at 3.6 g/L (44%); fluroxypyr (Starane) at 3.0 g/L (19%); and 2,4-D amine (Amicide 500) at 2.5 g/L (18%)) performed poorly. The chemical cost of the 5 effective herbicides is $476–1863/ha, excluding cost of labour. It would require $333–1304 million in herbicides alone to treat the current rubber vine infestation and even then, follow-up action would be necessary. In this context, these herbicides are best seen as useful tools for controlling scattered rubber vine plants. Foliar herbicides producing kills greater than 90% remain tools for controlling scattered rubber vine on higher value land or on strategic parts of properties.