29 September 1995

More scope for yield boosting

Do fungicides have a vital role in cereal production? That was the question posed by a

joint British Crop Protection Council/Society of Chemical Industries conference last week. The answer was a resounding yes – but there is much scope to get more from them as Charles Abel, Andrew Blake and Robert Harris report

FUNGICIDES boost cereal yields by about a quarter in the UK, and only slightly less in France and Germany, according to figures presented at the conference.

But big variations mean plenty of work is needed to allow growers to get more consistent results.

Mean yield response in winter wheat in the UK is 25%. "But its very variable from year to year," said ADASs Jim Orson.

"So there is considerable mileage in getting it right season to season, and there is a lot of effort going into this."

In winter barley the figure is 24%. "But thats more reliable from year to year," he said. The 15% average response in spring barley partly accounts for the swing to the winter crop, he suggested.

On the Continent the benefits from fungicides range from 13-18%, according to Ciba. But the figures mask much bigger improvements. Company trials in intensive cereal areas across the UK, France and Germany from 1991-94 found the best mildew treatment on winter wheat lifted output by 40.5%. In winter barley the best rhynchosporium treatment increased yield by 36%.

In England and Wales the average number of sprays used on winter wheat rose from 1.9 in 1988 to 2.3 in 1992. Corresponding figures for winter barley were 1.5 and 1.8. The number of passes on spring barley stayed the same at 1.1.

NEW CHEMICALS

New chemistry offers a breakthrough in fungicide use, said ADAS specialist Bill Clark. "For the first time ever, we could have an anti-resistance strategy that will suit farmers."

Anilinopyrimidines, strobilurins and plant activators all have different modes of action from existing chemistry and offer almost "endless possibilities", he explained.

They will make good partners for existing chemistry, especially triazoles, he believed. But a "huge educational programme" will be needed to get the best from them.

The traditional three-timing spray strategy based on the good eradication and persistence of triazoles will disappear, he says. Some of the new chemistry is non-systemic or non-eradicant and may need to be used prophylactically, so future strategies will be based on a whole range of timings.

Much scope exists for improving fungicide practice, but advice needs to be more farmer-friendly if the full benefits are to be realised.