12 April 2002

Roundups golden promise

By Charles Abel

TOTAL weed control is set to become a whole lot easier, with the launch of Roundup Gold, Monsantos latest development of the 28-year-old brand.

Designed to be simpler to use, it exploits a novel adjuvant to get glyphosate into plants faster and more effectively. Better rainfastness, more root uptake, faster plant kill and shorter cultivation intervals result.

"Glyphosate is glyphosate, to be perfectly frank," admits marketing director John Davies. "So we have been looking at how we can make it easier to use to bring benefits to the farmer.

"Farmers want the flexibility to use it when they want and to be able to get on with the next job on the field when they want."

At £75 for a 20-litre pack, Roundup Gold is expected to fetch a premium over comparable formulated products of almost £1/litre. "But it is not the price on the can but the price per hectare that counts," says Mr Davies.

No need for further additives and better field performance all mean lower label rates, delivering significant cost savings.

Compared with a typical 360g/litre glyphosate with tallow-amine adjuvant, Roundup Gold savings will be £1.80/ha on harvest management, £1.20/ha on in-crop weed control, £1.50/ha on desiccation and £0.60/ha on annual and perennial stubble cleaning, claims Mr Davies.

On a typical 750ha mixed cropping farm, that could save £1326 or 18% on glyphosate costs.

Key to the new formulation is the patented TranSorb adjuvant developed over the past seven years in the US and marketed there as Roundup Ultra Max. TranSorb helps glyphosate dissolve in water and fats, speeding its movement through the waxy surface of leaves, says technical manager Colin Stride.

Uptake is further enhanced by the low level of adjuvant used, which reduces plant damage during uptake, allowing more glyphosate to be taken up in total.

The net effect is one hour rainfastness for annuals and four hours for perennials, plus faster plant kill. Next operation turnaround is one day for annuals, two days for couch and five days for other perennials, significantly better than the current five to seven day standard. Application on dew is approved and water hardness has less effect.

The new formulation has been used in the Americas and Australia since 1999, but the UK is first to secure approval in Europe. The 450g/litre loading means less packaging and less product to handle.

Production in Antwerp is not expected to limit supplies. Some formulations will be dropped, but not Biactive or Sting.

Guy Gibson demonstrates the ultimate rainfastness test. Dip the leaves of a maize plant in field rate Roundup Gold (right), leave for 30 minutes, then chop the leaves off. "If removing the leaves altogether doesnt show whether the chemical has moved into the plant I dont know what does." Result a week later – dead plant. Do the same with an alternative "clean label" glyphosate product, including novel adjuvant, and the plant re-grows (centre), almost as well as the untreated plant (left).

&#8226 450g/litre glyphosate.

&#8226 £75 per 20-litre pack.

&#8226 One-hour rainfast.

&#8226 24-hour interval annuals, 48-hour perennials.

&#8226 No-glug pack empties in 16 seconds, no splashing.

&#8226 No extra additive, non-foaming.