Roundup Ready® cotton expansion

13 June, 2003

__*_Cotton CRC and CSIRO farming systems scientist, Grant Roberts, said Roundup Ready® cotton, which has captured 40 per cent of the market could expand to a higher level if growers continue their uptake of the technology._*

Speaking on the weekly CSD Web on Wednesday video program (28/05/03) on the CSD website, Mr Roberts said these developments had stimulated a new raft of research into the impact of the new technology.

While he welcomed its impact in reducing overall herbicide inputs, he said care was needed to ensure that it did not also result in Glyphosate resistant weeds in Roundup Ready® cotton systems.

“We have a PHD student based at ACRI, in conjunction with the CRC for Weeds in South Australia…developing a model so that we can determine if Glyphosate resistant weeds are at greater risk of development in a Roundup Ready® only system, compared to a conventional system, or compared to a fully integrated weed management system.

“This work is particularly important given that the Office of Gene Technology Regulator, and environmental groups, are particularly keen to ensure that we are not jeopardising our current systems with the release of these new transgenic technologies.

“So the community focus is really narrowing down on this particular Roundup Ready® technology, and making sure we manage it correctly,” Grant Roberts said.

He identified volunteer cotton as one area where management must be spot-on, noting the importance of cultivation as a primary tool for control, and also herbicides with a low residual capacity, allowing volunteers to be knocked, and the field put straight back into cotton.

“From our initial stream of research, we have narrowed it down to products such as Paraquat + Diquat (Sprayseed), a new product carfentrazone (Hammer), and glufosinate ammonium (Liberty).

“They were very effective against controlling volunteer cotyledon – first leaf plants out to about four and fifth leaf cotton,” he said.

He noted the need the stimulate the growth of volunteer seedlings well prior to planting, suggesting pre-watering (if feasible) to get them out of the ground, then selection of the appropriate non-residual herbicide at a rate based on the size of the plants.

With regard to ratoon cotton, he noted that it is difficult to control with herbicides, suggesting root cutting, pulling and cultivation as the best options.

Further Information: *Robert Eveleigh**, John Marshall, Greg Kauter or Craig McDonald