Bollgard® II resistance management plan outlined

21 July, 2004

___Monsanto Cotton Business Manager, Steve Ainsworth, says federal regulatory approval has been received for the industry-agreed resistance management plan for Bollgard® II for the coming season._

Speaking on the weekly CSD Web on Wednesday video (14/7/04), Mr Ainsworth said the plan varies somewhat from the resistance strategies adopted for Ingard® technology.

“Refuge management and refuge selection for Bollgard® II is vitally important to the sustainability of the technology. Bollgard® II, with the dual proteins, provides an excellent platform for long-term stability of resistance management, and obviously it’s important it is done correctly.”

Fellow Monsanto representative, Craig Farlow, outlined the range of refuge crop options. He said one option was an area of 5% pigeon peas, or 10% unsprayed cotton unsprayed for Helicoverpa.

__“There’s also the two summer crop options. Sorghum growers can look at 15% of their Bollgard® II area being sorghum, with three planting dates, and similarly with corn, where growers would be looking at 20% of their Bollgard® II area being planted with three planting dates once again.

“And the final option of course is to grow 100% sprayed cotton with no Bt applications, which basically means an equivalent area to their Bollgard® II area. Growers need to have their refuge located within 2km of their Bollgard® II cotton, and once again we do need those areas of refuge to be a minimum of two hectares and 48 metres wide.

“The extra stipulation for the coming season is that there is part of the unsprayed refuge within a Bollgard® II field or adjacent to a Bollgard® II field. That’s not all Bollgard® II fields but in very close proximity to one Bollgard® II field.

“One of the key points about refuge crops, is that they are there to produce susceptible moths and hopefully to dilute any potential build-up in resistance. So we need refuges to be managed in such a fashion that they are maintained to be attractive, hence flowering and being watered, aided by good agronomic management.

“A lot of growers have found that using Roundup Ready in the unsprayed cotton or using Roundup Ready in their conventional cotton system is a pretty positive refuge, because it allows them to make sure that that country is kept clean both in the current season but also in future seasons,” he said.

For dryland cotton, he advised that refuge options included sprayed cotton at an equivalent area of the Bollgard® II cotton area, or an unsprayed cotton option of 10% of the dryland Bollgard® II area.

Other options include, for each 100ha, 95.2 hectares of Bollgard® II cotton and 4.8 hectares of Pigeon Peas, or 87 hectares of Bollgard® II and 13 hectares of sorghum, or combinations of these refuges.

He said refuge options were slightly more complicated for dryland growers using double skip and single skip options, and because of the need for refuges to be planted into country with a similar fallow history and similar crop management.

However, he noted that most dryland growers would have adequate flexibility in producing detailed refuge plans, which could be developed in conjunction with local Monsanto business managers.

__CRDC research and extension manager, Bruce Pyke, said on the CSD video that it is essential that the industry manage Bollgard® II resistance well.

“There are some opportunities there with some of the new research, for example products like Magnet, the helicoverpa attractant, which might give us the opportunity to attract more heliothis or helicoverpa where we want them.

“The other area that is really essential, and always has been, is pupae busting. Certainly in southern Queensland and northern New South Wales it’s essential. Central Queensland of course have their trap crops; it’s absolutely essential that they’re managed properly.

“I think while Bollgard® II offers some great new opportunities for us in terms of perhaps increasing our profitability and allowing us to improve our IPM systems and to perhaps even manage some of our diseases like Fusarium and Black Root Rot a little better, we’ve still got to keep our focus on resistance management. It’s absolutely essential if we want to maintain the efficacy of Bollgard® II.

“It does offer great opportunities to improve our IPM, but we’ve got to focus on the issue of not using those broad spectrum sprays too early in the season, because that’s where we could come undone.”

Further Information: *"Robert Eveleigh**, John Marshall, Craig McDonald or David Kelly":showstaff.asp?staff=1