A new growth regulator plus fungicide for oilseed rape from Syngenta will increase the options for manipulating crop canopies in the spring, approval permitting.

A14049A contained paclobutrazol, a new active ingredient to oilseed rape, although it was available currently as Cultar in fruit, plus the fungicide difenoconazole (as in Plover), the firm’s Rod Burke said.

“This will be the first oilseed rape product including a true growth regulator.” Current growth regulatory products were primarily fungicides with PGR activity, he said.

An element of maximising the crop’s yield potential was making sure the canopy’s structure allowed enough light to penetrate to lower leaves and pods. Over dense canopies could be detrimental through reducing the numbers of seeds / sq m, as well as increasing lodging risk, Mr Burke said. “Early lodging can be a disaster, causing a 30-40% yield loss and impacting combining speeds.”

Two spring timings for A14049A had been investigated in trials. Early applications of 0.35 litres/ha at stem extension reduced height by over 12% – similar to full rate metconazole. The full 0.5 litres/ha rate of A14049A shortened the crop by nearly 19%.

Green bud applications had less effect on height – around 5% reduction from 0.35 litres/ha and 10% for the full rate – but had more effect on the canopy structure, Mr Burke said. “It compacts the pod layer producing fewer, larger pods.”

In Velcourt trials the green bud timing increased yields by over 1t/ha compared with the untreated.

The product would also have autumn recommendations. Syngenta hoped it would be available in time for spring 2008, approval permitting.