Transcript
Non-chemical methods of weed control:
benefits and limitations
Stephen MossRothamsted Research, UK
Farmers in EU will have to use more non-chemical control
methods because:
1. Fewer pesticides available due to EU regulatory action, and lack of new MOA
2. Increasing pesticide resistance, especially grass-weeds such as Alopecurus myosuroides
3. New EU regulatory action requiring farmers to adopt Integrated Pest Management (IPM)
http://www.pesticides.gov.uk (see European Union issues)
Loss of pesticides in European UnionHow many more can we afford to lose?
Data supplied by the European Crop Protection Association, Nov 2009
Comparative risk assessment and
substitution
Directive 91/414/EEC
Black-grass:“Atlantis” (mesosulfuron+iodosulfuron)
800 g/ha (2x field dose)
ALS TSR Proline 197 mutation
Three resistant populationsA susceptible
population
EU Thematic Strategy for Pesticides:Sustainable use directive
‘Member states should promote low pesticide input pest management, in particular Integrated Pest Management………’
‘…….with priority given wherever possible to non-chemical methods of plant protection…..’
‘…..setting quantitative targets and indicators aimed at reducing the impact of pesticides on human health and the environment.’
Non-chemical controlof grass-weeds
• Crop rotation• Ploughing• Delayed autumn drilling• Spring cropping• Fallowing• Prevent seed return and spread of resistant seeds• Mechanical weed control (harrowing or hoeing)• Competitive crops
– Higher seed rates (or at least avoid low seed rates)– More competitive varieties– Narrower rows
Black-grassAlopecurus myosuroides
Non-chemical control ofAlopecurus myosuroides
(black-grass) in winter wheat
Method Number ofcomparisons
% reduction achievedMean Range
Ploughing 25 67% - 20% to 96%Delayed drilling 16 37% - 64% to 82%Higher seed rates 15 30% + 8% to 53%Competitive cultivars 4 27% + 9% to 36%Spring Cropping 3 80% +70 to 90%Fallowing 1 70% +60 to 80%
Based on review, by Lutman & Moss for Syngenta, 2009
Higherseed rate
Rating the effectiveness of non-chemical control methods for Alopecurus myosuroides
on same basis as herbicides
Method Label rating
Ploughing MRDelayed drilling RHigher seed rates RCompetitive cultivars RSpring Cropping MSFallowing MRMeso.+Iodo. ‘Atlantis’ S
CRD Effectiveness claims: S = >85%; MS = 75 – 85%; MR = 60 – 75%; R < 60%
Weed control
Black-grass RRye-grass RWild-oats R
Why don’t farmers use morenon-chemical control methods?
1. More complex to manage – time constraints2. Less effective than pesticides3. Control levels more variable4. Control levels less predictable5. More expensive than pesticides6. No compensation following control failure7. May not reduce the need for pesticides8. Little visible evidence of success9. More risky (to consultant as well as farmer)10. Less return for supplier of pesticides11. May have adverse environmental effects12. Pesticides offer a ‘quicker-fix’ 13. Harder manual effort
2.2 black-grass heads/plant
170 seeds/plant
5.3 black-grass heads/plant
419 seeds/plant
450 wheat seeds sown/m2
150 wheat seeds sown/m2
Yielded 10.01 t/ha
Yielded 9.44 t/ha
22 June 2010
‘Enlightened’ farmer’s gallery
“Ten years ago we were drilling Claire at 80 –120 seeds/m2 in August, and were getting 8.5 – 10 t/ha. We thought we had cracked it by extending the growing season, but the open canopies quickly caused problems with grass-weeds. So now we are drilling later, at higher seed rates of 300 – 350 seeds/m2, and one of the first things we look for in a variety is how competitive it is against black-grass.”
Duncan Andrews, Gloucestershire farmerFarmers Weekly 20 May 2011
IPM (including IWM)Why has uptake been so limited?
“IPM has a very successful history of adoption by scientists, pressure groups and policy makers, but limited success in terms of adoption by farmers”
IPM in developing countries: the danger of an ideal. Morse & Buhler (1997). Integrated Pest Management Review 2, 175-185.
Poor adoption of IPM/IWM – why?
“Too much knowledge, not enough application”
‘TaylorReview,‘Science for a new age of agriculture’,
2010
“However, there is now widespread agreement that the focus of research funding and the accompanying mechanisms of reward and career opportunity have tilted the balance of agricultural science towards basic research and away from applied. This can severely compromise the translation of research into commercial practice. ”
Technology transfer issues
“…a lot of the eggheads in our research institutes concentrate on pure science and find it hard to communicate their ideas widely or simply enough to change everyday life”
Matthew Naylor, farmer, Farmers Weekly, 2009
“We believe it again goes, almost without saying, that relying upon the same tired methods to diffuse IWM will not lead to greater adoption”.
‘Investigating the human dimension of weed management: new tools of the trade’Doohan, Wilson, Canales & Parker, 2010 Weed Science 58: 503-510.
“Scientific research will be key to securing future food security” says the BBSRC
from ‘Food: avoiding a global security crisis’ in the RASE book, ‘Working for the future of agriculture’
“The application of scientific research will be key to securing future food security” says Dr Stephen Moss
Influencing farmersGetting farmers to do what you want by ensuring
that they are willing to do what you want them to do
Stephen Moss, Rothamsted Research
Farmer‘Expert’
Thank youstephen.moss@rothamsted.ac.uk
Good Canadian advice“ Once viable IWM systems are developed they
must be demonstrated at the field level and a consistent message must be given by multiplepeople at multiple forums over multiple years.
Patience is required by all involved, as meaningful change is usually a slow process”
‘Ongoing development of integrated weed management systems on the Canadian prairies’, Blackshaw et al., (2008)
Weed Science 56, 146-150