Archive Article: 1999/04/24

24 April 1999




The Dundee Conference combines new research paths with practicality. David Millar caught up on the latest at Crop Protection in Northern Britain.

WHY are the big agro-chemical multinationals again courting, or simply swallowing up, seed companies? Dr Andres Binder, of Novartis, explained to the Dundee Conference in his vision of the future.

Not only will genetically modified seed be commonly used, but seed treatments will grow in importance, and there will be changes in the way in which growers will prepare for planting.

"We will be going to the customer and selling a package of seed and active ingredient that fits," said Dr Binder. "In the future you will see a synergy from using inputs that fit."

He made it clear that the current controversy over GM crops would disappear when the next generation of GM varieties manipulated for advantages other that- herbicide resistance started to come through. "Oral vaccines or therapeutic proteins derived from crops will be on the market within five years," he added.

"Until now the consumer hasnt see the necessity of buying transgenic food because he has no advantage. If we can start getting into functional food making life easier, that will be something of which the consumer will have a new perception."

Concerns about antibiotic resistance developing through the use of marker genes based on antibiotic would also be dispelled with the introduction of new types of marker technology.

Biotechnology offered the possibility of opening up pest, weed and disease control. In weed plants with about 40,000 genes, only about eight different proteins were being hit by the herbicides developed in the last 30 years.

EX-ARABLE land presents its own difficulties for establishing the new species-rich grassland advocated under agri-environment measures such as the Countryside Premium Scheme.

That a re-think may be needed on some of the scheme rules was highlighted by Anna Christal, of the Scottish Agricultural College, which examined differing seed mixtures and management regimes over five years on two former arable sites near Edinburgh and Aberdeen. Nearly all 14 grass species used established well but management influenced what happened next.

Continued persistence of the sown species was favoured when cattle were allowed to graze the sward continuously, or when the sward was cut early and the cuttings either removed or grazed by cattle. Sheep, however, were more selective in their grazing habits, resulting in species loss whether from continuous grazing or aftermath grazing.

Leaving cuttings in the field had a shading effect on lower growing, less competitive species. The current schemes ban on cutting between April 15 and August 15 might also allow taller grasses to grow rank and inhibit development of the less competitive types.

ûNEWCASTLE is renowned as the nightlife capital of the UK and it seems that slugs too have more nights to party in the rainy north east.

Mark Shirley, of Newcastle University, found that slugs at Long Ashton in Somerset had just 75 nights with suitable conditions for feeding and damaging crops while their north-eastern cousins had 113 active nights in Northumberland.

Weather was, of course, the major influence. Slugs are at their funkiest when soil moisture is at least 26% and they need about 7íC to really get going with foraging, eating or mating. Northumberland may be lacking on the temperature front but rainy nights far outstrip those in the south.

What did it mean for the farmer? Mr Shirley explained that less intensive control measures, perhaps with less reliance on slug pellets and more on natural predators, could be adopted in the south west.

BUILDING a wall to keep slugs and pests out of your oilseed rape may not be such a daft idea. Scottish research has been finding links between weeds in crops, field boundaries and the incidence of pests and disease.

As well as detecting the influence of hedges, ditches or dykes, surveys over three years of around 50 crops each of winter oilseed rape and winter wheat have highlighted associations between certain weeds and pests such as slugs.

Weed specialist at the Scottish Agricultural College, Ken Davies told the conference there were clear connections between autumn weed cover and slug damage to rape in the autumn and spring. The presence of charlock and fumitory in crops coincided with an increase in slugs, while damage from the pest seemed to be reduced when annual meadowgrass was present.

Charlock was also seen to be associated with autumn flea beetle, day nettle and knotgrass with cabbage aphid, and fumitory or fat hen with striped flea beetle. Volunteer potatoes in the autumn increased aphids and leaf miner damage.

The more open boundaries around rape fields seemed to lead to increased pollen beetles and seed weevils, when compared with numbers in fields with hedges, dykes or banks. Leaf miner and slug damage led to higher glucosinolate levels but pod botrytis was associated with reduced glucosinolate levels.

Weeds were not found to be so influential in the wheat crops as far as numbers of pests or disease level was concerned. However, some autumn weeds appeared to lower specific weights, while some spring weeds were associated with increases in thousand grain weight.

MIXTURES of winter barley varieties could be grown to benefit farmers with low inputs and high yields without giving maltsters any real difficulty with the end product.

Doubts about the quality of harvested crop have always held back the concept of improving disease resistance by mixing cultivars. Dr Adrian Newton, of the Scottish Crop Research Institute, unveiled research showing a mixture of varieties with a common parent could give the evenness of harvested grain demanded by maltsters.

Splash-dispersed diseases such as rhynchosporium and Septoria nodorum can be curbed by variety mixtures so three years of trials looked at differing blends of malting and feed varieties for their ability to withstand rhynchosporium in particular. A key finding was that a combination of three different varieties gave the best response in reduced need for fungicide, with the best yield return, without increasing variation in the harvested grain unduly.

When malting trials were carried out on a blend of Maris Otter, Halcyon and Pipkin, the mixture was found to be superior for hot water extract to any one of the components.


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