Crop Protection in Southern Britain conference highlights major challenges ahead

Forecasting trends and planning for some major challenges in the future were key messages for delegates to take home from the recent ‘Crop Protection in Southern Britain’ conference. Organised by the Association of Applied Biologists (AAB) and supported by Bayer CropScience, NIAB TAG and BCPC, the event attracted over 90 delegates – an increase of over 30% on the previous conference. The first-class programme of 43 papers, including 3 invited papers, covered: grass weed and disease control in cereals, crop protection in oilseed rape and other broad-leaved crops and the impact of new legislation on pesticide use and cropping.

The opening session, chaired by John Cussans began with a paper from Dr Stephen Moss, Rothamsted Research, focussed on herbicide resistance in the UK. His paper gave an update on the status of key herbicide resistant weeds since 2005. Black-grass (Alopecurus myosuroides) is regarded as one of the most important herbicide resistant weeds in Europe. In 2005, results from screening assays conducted between 2000 and 2004 revealed that resistance had been found on 2,085 farms in 31 counties in the UK. “It is not unreasonable to suggest that today, there are at least 16,000 farms in the UK with black-grass which is affected by some level of herbicide resistance and this has now spread to some 34 counties. Herbicide resistant grass-weeds now occur widely in all the main arable areas of England,” said Dr Moss.

Similar trends are also emerging with Italian rye-grass (Lolium multiflorum). In 2005 herbicide resistant rye-grass was found in 324 farms in 28 counties, this has now risen to some 450 farms in 33 counties. Although resistance in rye-grass is not as significant as black-grass, the expectation is that it will continue to develop. Resistance has also been found in wild-oats, common poppy, scentless mayweed and groundsel.

"Glasshouse screening assays have revealed resistance to mesosulfuron + iodosulfuron (e.g. Atlantis), the most widely used herbicide for black-grass control.
This is worrying especially as no new products, with new modes of action, are on the horizon. Small scale surveys can give a good indication of resistance trends, but molecular studies need to be done in conjunction with whole plant studies,” advised Dr Moss.

Having forecasted the trends, Roger Bradbury, Bayer Crop Sciences outlined the need for well-defined resistance management and stewardship programmes to be put in place in order to maintain the usefulness of products such as Atlantis. Unless black-grass populations are very low, a pre-emergence product – to reduce populations – is to be recommended. Key stewardship messages include: correct use, integrating cultural control measures, applying with the adjuvant Biopower, using in sequence with an effective non-ALS herbicide (i.e. another mode of action) and monitoring weed control effectiveness. Adopting these measures will help to get the best out of the product and ensure effectiveness against black-grass in the future.

Anne-Sophie Walker from INRA in France initiated the disease control session by looking at the evolution of fungicide resistance in French populations of the economically important, yield reducing disease Septoria in wheat.

Stuart Knight, NIAB TAG, revealed that the performance of azole fungicides had fallen off since the mid 90’s. With the uncertainty of new chemistry coming through the role in fungicide programmes remains crucial. It is vital that over-dependence on DMI fungicides (the triazoles and Prochloraz) is avoided and that intelligent use is made of alternate chemical groups.

The conference concluded with a session on the impact of new legislation on pesticide use and cropping, chaired by Dr Colin Ruscoe, BCPC. Grant Stark, Chemicals Regulation Directorate (CRD), set the scene by outlining the legislation that underpins the Thematic Strategy for Pesticides. The new Pesticide Authorisation Regulation comes into force in June 2011. Although the process remains largely unaltered from the existing one for product approvals, there are some significant changes in the principles that underpin the regulations, in particular assessment changing from risk based to hazard based, with comparative assessment and substitution of “less safe” products. How this is going to work in practice and what the impact will be is being clarified, but with the current review programme it will mean that the impact will largely start to be felt as products come up for review in 2015/2016 onwards.

"The directive on the Sustainable Use of pesticides is the first substantive piece of EU legislation governing the use of pesticides and comes into force in a number of stages from 2011 to 2020,” explained Mr Stark. “The key objective is to raise standards across the EU member states. One of the features of this will be the need for each member state to develop National Action Plans to reduce the risk from pesticides and promote the use of low input systems.”

"Most of the measures which form part of the National Action Plans already feature as part of existing very effective UK statutory and voluntary controls,” said Mr Stark.” Our policy is to introduce any new legislation or regulatory processes only where absolutely essential. However there are a few areas where changes to the UK approach will need to be made to ensure that they are consistent with the requirements of the Directive.” These changes include:

The establishment of a system of training and certification programmes to be in place by 2013:

• The introduction of a certificate of competence to sell pesticide products from 2015;

• The requirement for application equipment to be tested more frequently from 2020;

• From November 2011, a permit to spray will be required from CRD for aerial spraying;

The Water Framework Directive will require some changes in order to comply with the requirements.

"A lot of the measures outlined in the Directive are already taken by UK farmers, but some Member States will want to see a more regulatory approach being taken, but the UK Government will want to engage with the industry to have a cooperative approach to further minimise risks associated with pesticide use,” advised Mr Stark.

"600 active substances have already been lost and pesticides are already highly regulated,” said Janet Williams from Bayer CropScience, who provided the manufacturers’ point of view. “The new legislation is a key issue for farmers, with the potential for further loss of active substances and products. This is particularly worrying given that with an increasing global population, there is a continuing need to keep weeds, pests and diseases in check to ensure good crop yields so that we can maintain both a staple food supply and a variety of crops.”

Concluding the session James Clarke, ADAS Boxworth looked at the impact of changing pesticide availability. “The loss of pesticides, due to the failure to meet water quality legislation, is likely to have a huge impact on crop yields and therefore profitability of UK farming,” he warned. “The potential loss of herbicides due to changing approvals legislation is also likely to have a significant impact in terms of increased yield losses. The consequence of this could be large increases in costs, reduced gross margins of 40% or reductions in yields such that the production of a specific crop may no longer be viable.”

Papers from the final session Impact of new legislation on pesticide use and cropping are available to download from the BCPC website at: http://www.bcpc.org/press_Crop-Protection-conference-highlights-major-challenges-ahead_175.html.