A new online tool that aims to help growers manage their oilseed rape canopies more efficiently has just been launched by BASF and ADAS.

The site, www.totaloilseedcare.co.uk, provides updated photographs of crops around England, with a measurement of their Green Area Index, together with appropriate management advice.

“The GAI is an effective way of assessing canopy size and is useful when deciding what action to take with regard to fertiliser and growth regulation,” said BASF oilseed rape product manager, Diane Heath.

“Economic benefits from plant growth regulators have been observed for crops with a GAI greater than 1 in March or 2 in April.” The optimum GAI at the end of flowering is 3.5, she noted.

The photos will be updated monthly in March and April, but the project will follow crops through to final yield, Ms Heath said. It is also planned to include weekly sclerotinia bulletins on the site, which are expected to begin within the next week.

Example advice:
Location: Great Dunmow, Essex
Photo date: Wednesday 15 February 2006
GAI = 2.44, Nitrogen in crop: 122kg N/ha

Management Advice
This canopy is greater than the optimum size and will generally give an economic response to a full rate of a growth regulatory fungicide even when disease control is not needed. This crop already contains 122 kg N/ha so total fertiliser nitrogen should be reduced and the first split of nitrogen may not be required.

Apply the growth regulatory fungicide from mid-stem extension, once the crop is growing actively, usually from Mid March into April.