Integrated control of Sclerotinia disease in celery and lettuce

By Tracey Moreton (Waitrose CTP PhD student)

My Journey

Starts in the beautiful region of Murcia, Spain. Here I visited celery and lettuce farms in Los Alcazares and Aguilas where I set off to collect samples of the plants infected with Sclerotinia. Over a two-day period, I visited commercial and organic farms collecting the appropriate samples, from where they would be transported back to England for preparation of experimental work.

New Partnerships

Phase I of the project would not be possible if it were not for the support and help from all the staff and farmers in Spain at G’s. In particular Pedro who was a mound of very useful information and was as enthusiastic as myself and to James and Mendez for being my chauffeurs.

The Science

There are several factors that perpetuate Sclerotinia incidence on crops, such as climate and the extensive host range of the pathogen. In addition, the disease not only presents itself at cultivation but in storage as well.

The project topic that I will be investigating is Sclerotinia sclerotiorum Which is a soilborne fungal pathogen that causes stem and crown rots in a wide range of crop plants resulting in extensive economic losses worldwide. The fungus can survive for several years in the soil as sclerotia, which when close to the soil surface germinate carpogenically to produce mushroom-like apothecia. Subsequent release of air-borne ascospores then initiate the infection process. Control of S. sclerotiorum focuses on the prevention of ascospore infection with the use of fungicides, but generally there are no attempts to eradicate sclerotia. This project aims to explore practices that reduce sclerotial survival in order to improve Sclerotinia control in celery and lettuce in Spain.

The Plan

The main objectives are to:

  1. Collect sclerotiorum isolates from UK and Spanish lettuce and celery crops and characterise using molecular genetics to identify any differences in population structure.
  2. Determine the temperatures required to kill sclerotiorum sclerotia or prevent carpogenic germination for UK and Spanish isolates to evaluate the feasibility of solarisation.
  3. Investigate other means of killing sclerotia such as bio-solarisation, bio-fumigation and anaerobic disinfestation.

Keywords: Sclerotinia sclerotiorum, stem rot, crown rot, apothecia, bio-solarisation, bio-fumigation, anaerobic disinfestation.

The first trip was a success and the Spanish samples are now being cultivated to grow sclerotia.


Spanish samples placed in a constant 20oC room


A. B. C. D. 


A. Celery placed on damp paper and left to develop sclerotia. The appearance of mycelium (white fluffy structures) will eventually produce the sclerotia.

B. Small dark circular characteristics of sclerotia appear.

C. Lettuce sample with sclerotia.

D. First harvest of Spanish sclerotia from lettuce and celery samples




Digging up dirt on cover crops

By Mandy Stoker (CTP Student)

I was recently asked to visit a land owner who had a rather difficult and sensitive problem to deal with.  The gentleman had been working in partnership with a business man to clean up and restock two beautiful fishing pools which were to be opened up for leisure fishing later this year.  They had worked hard for a couple of years, and felt they had cracked it. Then, disaster.  The water quality had suddenly changed. Foaming water poured from a land drain and the pH had risen to unacceptable levels for fish to survive.

On further investigation I could see an open field on higher ground above the pond.  The field was totally sodden with muddy water streaming along big ruts into drains, and straight into the pond.  The field had been planted with maize (year on year) and left uncovered over winter. Frankly, it looked a mess and I felt sad for the guys who’d been making great efforts to clean the ponds.

Soil run off is a big problem. Our top soil is eroding at a staggering rate. It gave rise to the alarming headline in the Farmers Weekly in Oct 2014 “Only 100 harvests left in UK farm soils”.  Some 4.3bt of carbon/year that was in the soil is now in the air and contributing to climate change.  The lack of top soil and an increasing amount of rainfall has exacerbated the problem of run off.  At the Paris Climate Change Conference special attention was given to soil as a primary solution to mitigate climate change. It was proposed, and is now part of the Climate Change Agreement, that there should be a target for the increase of carbon in soil at a rate of 0.4% (or 4 per 1000 initiative) per annum for 20 years.  Given that it takes some 100 years to produce a 1cm of top soil what can we do?

Cover crops present a solution that would have certainly helped with the gentleman’s problem above.  A cover crop is usually grown in between the cash crop.  There are many plants that can be used as cover crops, each bringing a whole wealth of different benefits.  Cover crops can not only stabilise soil, reduce erosion and prevent the leaching of nitrogen, they can suppress weeds, lock in nutrients, improve soil structure and add to the organic matter.

Over the next few years I’m aiming to measure the increase in carbon stored in soil with the use of cover crops together with other farm practices or treatments.    The key is in the microbiology of the soil.  Planting of plots is occurring in the next couple of weeks and the worm counting (amongst other things) will begin.

Will cover crops provide a sticking plaster solution to our soil problem or can they have a more important sustainable role as a feedstock of carbon into soil? Watch this space.




Soils and the 25 Environment Plan

By Edward Baker (Waitrose CTP Student)


With increasing public and political significance, modern environmentalism has begun to distance itself from a Laissez-faire attitude around natural ecosystem management. The most recent addition of legislation and policy direction, the 25 Year Environmental Plan, attempts to address the pressures facing the UK’s natural ecosystems from anthropogenic disturbances.

Well documented and publicised environmental concerns such as the demand for clean air and water, increase of biodiversity, sustainable use of natural resources, and mitigation of climate change are acknowledged in the plan. Additionally, attention gained through TV programmes such as the BBC’s “Blue Planet”, has catapulted plastics into a prominent position.

Along with these noted issues, the forgotten link in the water, food and energy nexus, Soils, has started to develop momentum. Whilst not excessively highlighted in the plan, it’s inclusion is a significant step in realising the reliance we place on soils for food production and further ecological services. Initiatives surrounding soils discussed in the plan include the introduction of a replacement to the Common Agricultural Policy, changes to regulation on fertilisers and pesticides, and investment into the development of soil health.

Soils’ presence displays an increased collective awareness, though the details in the plan fails to provide meaningful solutions or address any ground actions, rather, it merely specifies future intentions. This has galvanised a variety of organisations to provide critical feedback and solutions to combat soil degradation. Below is a summary of the key opinions and attitudes surrounding the plan which arose during a workshop by the Soil Research Centre at the University of Reading.


Soil Health Index

The proposals to develop a Soil Health Index was met with a healthy amount of scepticism. Soils are a heterogeneous medium and variation can exist at both farm and regional scales. As such, the index must be adjustable to local conditions and be conveyed in a meaningful way as to not cause confusion, especially if being used in place of the Common Agricultural Policy payment scheme.

During the workshop, the other major concern voiced with constructing the index was the measurement of levels of depletion. A suggestion was given to base soil health indicators on local natural systems and observe how characteristics are altered given anthropogenic disturbances. Whatever the agreed protocol, it was established that any decision must be rapidly mapped and implemented for the index to progress.


Guidance for Improving Soil Health

Alongside the Soil Health Index, it was realised that a new set of management practises and guidelines would be indispensable. Management practises including; mixed farming (or linking arable and livestock farms), cover cropping and effective crop rotation, were among those suggested to improve Soil Health. The idea of promoting sustainable management techniques overcomes the issues discussed on soil heterogeneity and defining its health status.

Therefore, education and training will be important in providing such guidance on management and soil health. A flexible, multi-institute, farmer led, local system which interlocks with existing schemes would provide an invaluable tool to encourage this. However, it is beyond farmers that we must look to protect our soils. Commercial demands led to intensification of farming practises creating an unsustainable environment. Without providing information to the consumer and retailer, it is unlikely that a soil health initiative, whether index or management based, would be able to combat financial pressures.


Public Money for Public Goods

With a resounding response, the group agreed that rejuvenation and improvement of our soils health is likely to be a long-term objective, much greater than 25 years. Supporting sustainable management practises over short term improvements was deemed essential to achieve targeted soil replenishment. This could be encouraged by providing financial benefits for maintenance of good soil health or practises which is likely to encourage risk adverse farmers to favour innovative and beneficial practises.

The idea behind funding such maintenance is that the benefits felt from improving Soil Health ranges beyond the farm owner. Public goods such as; carbon sequestration, clean water, and increased biodiversity amongst others, would benefit the whole of society.


Education and Outreach

It was observed as a whole that the plan places emphasis on farmers managing soils sustainably and making the most of natural capital. However, realities are that consumers and supermarkets drive production rates and in turn increase soil degradation. The increasingly urbanised public are disconnected from the land. Without conscious purchasing and public education, these trends are likely to continue. Whilst the Plan does attempt to bridge this divide through education, there are missed opportunities.

Furthermore, encouraging younger generations to become engaged in nature would be a positive step forward, however, the group noted that this education needs to be linked with the farming community not just curtailed to nature reserves. The direction for education should also extend past pre-school. There should be backing for young and experienced farmers to cooperate both within the farming community and externally with researchers. This increase in cooperation will possibly create a society where the burden of sustainably managing our soils is not placed solely on the backs of farmers.


Closing Thoughts

The plan published is a strong statement of intent from the government to drive our society to be more environmentally conscious. The protection of our soils from degradation has started to be addressed, however, due to their rapid depletion rates, it is questionable whether this is enough. The development of a Soil Health Index may be able to replace and improve upon the existing CAP programme. Whether it would be better to focus on positive management practises considering the variable nature of soils and the timescales associated with improving soil properties is a question for government. In the eyes of the group, this system seemed more productive at improving the health of our soils. This idea supports movement away from short term gains at the expense of the natural ecosystems and considers a more holistic view.

One key and clear message is that farmers are the custodians for our soils. Support ranging from financial incentives to education is necessary to allow for them to sustainably manage the natural ecosystems they cultivate. Without such backing it will be impossible to compete with market drivers and demands and we may see the decline of our prestigious countryside.


Agroecological Crop Protection- yet another acronym?

By Hannah McGrath (Waitrose CTP Student)


In early February, I left Luton airport on a dreary Saturday morning for the sunshine in Volterra, Tuscany. I was off to attend a course on Agroecological Crop Protection (ACP), a concept I knew little about but aware that by the end of the week I would know more! Now I have the opportunity to pass some of that knowledge onto you…


What is Agroecological Crop Protection?

At its most broad, ACP could be described as a cropping system that has been designed with biodiversity and soil health as the two most important goals for the farmer. By improving the quality of these two components, crops should be able to tolerate the stresses placed upon them by the environment and so the farmer does not have to add any inputs to the system. For instance, by adding flowering plants within the field, biodiversity increases. These flowers might be able to provide food for natural enemies such as parasitoid wasps, which can control outbreaks of crop pests without requiring chemical sprays.


Why does Agroecological Crop Protection exist?

Agroecological Crop Protection was developed by predominately French agricultural researchers as a result of their many years of experience working and researching agricultural issues. Together this group saw that Integrated Pest Management (IPM) is a buzzword, catch-all phrase used by many to describe their attempts to control crop pests in non-chemical ways. But, the reality they encountered was that the control pests and diseases often heavily relied upon chemical control, despite the methods being called IPM. This group also saw that the use of many of the chemicals that we use to control insect pests, weeds, and plant pathogens are being restricted by governments. Therefore, there is a need to develop cropping systems that can function without high inputs. Therefore, the researchers mainly from INRA and CIRAD, two French agricultural research institutes came together to propose ACP as an improvement on current agricultural practices.

Eventually, ACP has been written up in a book edited by J.P. Deguine, C. Gloanec, P. Laurent, A. Ratnadass and J.N. Aubertot, but the entire book contains work from 56 different authors around the globe. As many of the editors and authors of this book led the course in Volterra, I was literally from the people who wrote the book on ACP!

Figure 1. Agroecological Crop Protection Book.

I realise that you may be thinking that ACP and IPM sound like essentially the same thing, and in many ways they are. They both are agricultural concepts with an acronym developed to try and build more sustainable agricultural systems. For other people, the textbook definition doesn’t matter much to them, instead understanding the actions that take place to control pests, weeds and diseases out in the fields is what really matters.

Ultimately, Agroecological Crop Protection does attempt to further the relatively old concept of Integrated Pest Management and given that we are living in a regulatory environment where the use of chemicals is highly regulated, it is sensible to be working towards the goal of lowering chemical inputs.

Figure 2. The Tuscan landscape didn’t disappoint. Here was the view from an organic farm we visited to learn about how they were implementing Agroecological Crop Protection methods.


My personal reflections on the course

The course had a truly global attendance, with researchers from Costa Rica, Vietnam and Martinique making my journey from Rothamsted look rather tame. The opportunity to learn about the huge variety of cropping systems around the globe expanded the bubble I have formed around the way I see agriculture. Beneath all of case studies and anecdotes I heard, were farmers who cared deeply about their crop and the environment they worked in.

I also began to appreciate that agriculture and the many issues which farmers face shouldn’t be looked at in isolation. If we only think about pest management, soil health or crop nutrition on their own, we may be unintentionally making a problem worse or might miss a single solution for multiple problems. Whilst Agroecological Crop Protection may sound unachievably optimistic and futuristic, it at least gives a framework for further improvements in agriculture. It’s now up to me and the other attendees at the course to work out how that might look in the commercial agricultural settings we work in.

Waitrose CTP Annual Conference

By Roz Wareing

Waitrose CTP students, supervisors and board members attended the 2018 Waitrose Science Day, held at Scarman House. University of Warwick. The students battled snow and wind to attend our first annual conference event at the end of February.

On the first afternoon the students participated in a training workshop ran by colleagues from the Centre of Eco Innovation (CGE), Laura O’Keefe and Zoe Detko. Laura and Zoe are ex PhD students and currently work on the CGE project as Innovation Fellows. They discussed the benefits of an industry focused PhD, and the challenges involved with the collaboration with academia and industry. The workshop also taught the students varying methods of engagement for different audiences.

For the second and third day the students attended the sessions organised by the Waitrose Science Day. There were a range of presentations from academia presenting their area of research and the CTP projects based at their institutes. Emma Garfield from G’s delivered an excellent presentation to the potential industry partners, willing them to get involved with the CTP. Emma focussed on the huge benefits and opportunities a PhD student can provide to their host company.

The students had an opportunity to engage with our industry colleagues during evening poster reception. Each student showcased a poster about their project and delivered talks to other academics and industry.

The last morning allowed opportunities for industry and academia to discuss research interests and ideas for PhD projects. The discussion groups related to several areas of interest; Water, Soil Biodiversity, Pesticides/IPM and Protected Crops. The CTP hopes to see these ideas flourish over the next few months awaiting the next call of project proposals and we look forward to the next student training event coming up in the summer.

Climate change risk for half of plant and animal species in biodiversity hot-spots

Up to half of plant and animal species in the world’s most naturally rich areas, such as the Amazon and the Galapagos, could face local extinction by the turn of the century due to climate change if carbon emissions continue to rise unchecked.

The Amazon, Miombo Woodlands in Southern Africa, and south-west Australia are among the most affected places in the world, according to new research.