Late blight: an integrated approach

The development of fluazinam-resistant blight strains has placed further pressure on spray programmes. It has been estimated that growers spend £20m each year on fungicides in an attempt to keep blight at bay.

Dr Sue Cowgill, senior scientist at AHDB says late blight is very much in the spotlight at the moment because both the pathogen and the availability of control measures have changed. The push to adopt integrated pest management (IPM) is across the board, she adds, with growers keen to adopt new approaches.

IPM is by no means a novel concept but it focuses on adopting a range of cultural and chemical methods to target development of pests and diseases at different times of the year to create a more robust control programme and a sustainable approach.

‘Overall, changes in chemical regulations makes us feel that there are fewer new actives coming to the market, and some of those that are available are being lost,’ Dr Cowgill observes. ‘Using IPM can take the pressure off the remaining actives by minimising the negative effects of resistant pests and diseases.

‘In the case of late blight, the use of resistant varieties strengthens all other control options if, for example, the weather is bad and sprays cannot be applied. Practical implementation of IPM can be a real challenge though,’ she warns. ‘Growers are aware of the options but they need to be able to combine these to meet their other needs.’

Although the lifecycle of blight is well understood, varietal resistance in some of the most widely grown crops is relatively low and there is less flexibility and margin for error. This means the numbers of precautionary fungicide applications are high and this has seen the development of fluazinam resistant strains emerging. Despite growers being offered a glimmer of hope this season with the newly available Zorvec Enicade (oxathiapiprolin), which offers longer spray intervals and lower use rates with no known cross-resistance, experts are urging growers to adopt new forecasting methods, including guidance formulated by pathologists at the James Hutton Institute, Dundee. The Hutton Criteria offer new treatment thresholds which are said to give growers increased confidence in risk-based spray applications while reducing unnecessary use of fungicides.

Dr Alison Lees, plant pathologist at JHI explains: ‘Better disease forecasting is very important. Our new model has been very successful in testing a new sustainable fungicide programme. We are very aware of the high risks for growers associated with blight epidemics but so far during field trials no blight has been found, chemical usage was reduced, and input costs were lower.’

For the full article see our July/August edition

 

Western technology meets the developing world’s needs

The World Potato Congress in Cusco, Peru, was a sell-out, according to the organisers. Given the fact that the International Potato Center (CIP) was heavily involved, the emphasis was on food security in the world’s poorer nations.

Douglas Harley, managing director of Gygnet Potato Breeders at Milnathort near Perth, is a long-serving member of the WPC organising committee. ‘The conference was impressive and very well attended,’ he told Potato Review, ‘and for me it was a chance to see the home of the potato.

‘With CIP as the principal organiser there was quite a strong scientific theme, as you’d expect. There was a lot of focus on Latin America and on using potatoes as a means of feeding the starving rather than concentrating on frozen French fries, for example. When WPC gets to Dublin in three years time the emphasis might be more commercial. We have the intention of moving the event around the world from developed to less developed nations to achieve that balance and allow people see both sides of the coin.’

WPC

Participatory varietal selection of biofortified potatoes in Ambato in Huancavelica, Peru. Two communities Tacsana and Castillapata are growing and helping to select new biofortifed varieties of potatoes. The potatoes are higher in zinc and iron and are being developed to help counteract pervasive anemia. CIP is partnering with the grupo Yanapay to select possible varieties for release.

‘World Potato Congress Inc. was conceived as a global networking organisation which uses its conference to achieve that aim but there is a lot more going on behind the scenes as well,’ Mr Harley explained. ‘We’re trying to bring together western technology with a Third World developing industry. It’s a not for profit organisation and it’s all about promoting the benefits of potatoes to the wider society. And as a seed merchant, a global conference allows me to look at different opportunities in terms of new variety development.

‘There is currently quite a lot of work on genetics and manipulation of DNA, some of which is quite beyond me but which seems to be moving at speed in various different parts of the world. True seed certainly has a place in the Third World but I’m not sure how competitive it will be on yield and processing quality which are the main drivers for development. It is difficult to see how an inbred line will give consistency of factory output.

‘You have to remember that true seed has a four-week delay in canopy cover compared to conventional seed with it’s large reserve of starch which it uses to grow rapidly. There is a saving on seed production and distribution but there is also a yield penalty though in parts of Africa, for instance, where there is a long growing season, that disadvantage might be less significant.’

AHDB’s Claire Hodge came back from her Peruvian trip full of enthusiasm. ‘It was an amazing experience and the location was quite special,’ she said. ‘There was a lot of time devoted to the humanitarian side of potato production and to subsistence farming, but what I found interesting was that there was also a lot about sourcing robust seed, whatever system you are working with.

‘Among the scientific elements there was discussion on genetic developments and technology without anyone actually using the words “genetically modified”. There are huge steps forward on that and on moving from tetraploid to diploid production. It looks like we’re getting closer to reducing the yield penalties but if we’re talking about nutritional benefits and reducing the impact [of potato production] on the environment, then it seems there is now a shift and that reduced yields might become more acceptable.’

For the full article see our July/August edition

 

Big savings from a small outlay

Relatively limited expenditure can greatly improve the efficiency and running costs of potato box stores, the results of a major industry trial have confirmed.

storage

The two-year project has identified a number of ways in which owners of both existing and new stores can improve their performance by either retro-fitting a range of features to improve the even-ness of airflow throughout the store, or installing them as original equipment. The trial was ‘industry led’ with 70% of the £800,000 funding coming from Innovate UK.

The project was run in a specially built 1/3 scale model store at Sutton Bridge Crop Storage Research (SBCSR) and in commercial facilities, including units operated by Branston Ltd. The work represented possibly the most detailed monitoring of airflow ever completed in a potato store, says Mr Cunnington says Adrian Cunnington, AHDB’s head of crop storage research.

‘We took measurements at every slot in the face of the box store at both ends, so on a stack that was 10 boxes wide and eight boxes high that was a total of 160 airflow monitors,’ he recounts.

‘In standard form we found that nearly 75% of the air produced by the fans to dry and cool the crop wasn’t going through the boxes but was disappearing everywhere else.

‘There was massive inefficiency in such systems so we started to examine how we could improve things by installing plenum walls and testing the use of side and top sheets. These measures improved airflow dramatically – by as much as factor of three.

Prior to this latest project, AHDB and FEC Energy had carried out a trial that indicated huge differences in the efficiency with which energy was being used in potato stores.

‘That started to ring alarm bells because we were finding running costs of £4/tonne in the best stores but £12/tonne in the worst,’ Mr Cunnington recalls. ‘We began to examine the causes of those differences and there are a number of things which came into play.’

The project highlighted one key difference between bulk and box stores, explains Ray Andrews, managing director of lead partner Crop Systems Ltd. ‘Bulk stores with under-floor ducts work well because the air literally has nowhere else to go but through the crop. In box stores the air comes out of ducts above the crop and we have much less control over where it goes. We found some instances where boxes at the far end of the store saw virtually no air movement at all.’

For the full article see our July/August edition

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