Tag Archives: agriculture

Pick and mix 5 – more links to ponder

Another set of links that interested me enough to read (and this week, watch) them all the way through.


Interesting (tongue-in-cheek) post about using Ribwort plantain as a garden flower

Jo Cartmell (@watervole) on how to turn your boring lawn into a beautiful wildflower meadow

Gretchen Vögel asks – Where have all the insects gone?

How ploughing and deep tillage methods are harming earthworms worldwide

We have been telling our students for years that one of the advantages of biological control compared with conventional use of pesticides is that prey are unlikely to evolve resistance to natural enemies.  Well, we were wrong – here is a story about a pest weevil that has done just that  – unfortunately behind a pay wall

Insects and ethics – Some very interesting points, but as much as I love insects which I do passionately, I am very happy, that ethically speaking, they are not classified as animals. Research would be impossible. That said, all insects in my garden live a free and happy life and are never knowingly killed, not even if they are on my bean plants 🙂

A nice article about photographing spiders and also mentions ethics

Here Markus Eichhorn writes about the questionable ethical standpoints of some otherwise reputable scientists from the last century

An interactive blog post about global crop diversity and eating habits – quite revealing, try it and see

An interesting and well produced short video that could be useful if you want to explain how sustainable management of tropical forests helps the planet and why you should only buy FSC certified products


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Filed under Pick and mix

Mind the gap – time to make sure that scientists and practitioners are on the same page

I have deliberately used the same title for this post as my 2017 Editorial in Annals of Applied Biology and if you were to run it through Turnitin™ you would find a very high percentage similarity indeed 🙂 I had originally planned for this post and my Editorial to appear simultaneously, but thanks to modern publishing practices, the January issue of the Annals of Applied Biology, hit the virtual newsstands in mid-December and put the kibosh on my cunning plan.


Once a year I am wheeled out to do a guest lecture to the final year agriculture undergraduates on the Global Food Production module here at Harper Adams.  I start off the lecture by reminiscing about when I was an agricultural zoology undergraduate student at the University of Leeds in 1975 and was introduced to the concept of Integrated Pest Management (IPM), or as it was termed then, Integrated Pest Control.  I was very much taken by this idea and on my next visit home, approached my Uncle James, a farmer, and explained the concept to him and suggested that he might like to implement it on his farm.  To my surprise, he was not convinced by my arguments, and replied with words to the effect, “It all sounds rather tedious, and after all, I can do all my pest control much more easily using a tank mix, so why should I bother?”.  This attitude was, at the time widespread among the UK farming community and elsewhere despite the concept having been formally discussed in the scientific literature since the late 1950s and early 1960s (Stern et al., 1959; de Fluiter, 1962).  Despite the benefits of IPM being recognised and extolled IPM by researchers and agronomists for many years, take-up by growers has been much slower than expected (Kogan, 1998; Hammond et al., 2006). Resistance to the adoption of integrated pest management is not new, Benjamin Walsh writing in 1866 wrote

Let a man profess to have discovered some new patent powder pimperlimplimp, a single pinch of which being thrown into each corner of a field will kill every bug throughout its whole extent, and people will listen to him with attention and respect.  But tell them of any simple common-sense plan, based upon correct scientific principles, to check and keep within reasonable bounds the insect foes of the farmer, and they will laugh you to scorn”  Benjamin Walsh The Practical Entomologist

Why, if IPM is regarded as being of such paramount importance to sustainable crop production, the European Union for example passed a directive recently (2009/128/EC) requiring all member states to pass legislation to make sure that all professional growers at the very least adopt the principles of IPM, is its adoption so slow.  Hokkanen (2015) cites three main impediments to the adoption of IPM, science funding, political interference and economics.  As an applied entomologist I know from bitter experience, that there is a lack of willingness by the UK Research Councils to fund basic applied science i.e. grants to aid researchers to establish much-needed new economic thresholds are very unlikely to be funded.  Hokkanen (2015) also points out that whilst the political landscape now includes IPM, different governments have views, not necessarily based on science, about what are acceptable items for the IPM toolbox, genetically modified crops (GM) and neonicotinoid insecticides being just two such examples. Thirdly, as Hokkanen (2015) points out the ability of farmers to fully adopt IPM practices, is often out of their control, but is decided by market forces and social and political pressures, GM crops and neonicotinoids again serving to illustrate this point.

As Felicity Lawrence writing in the Guardian says “British farmers growing wheat typically treat each crop over its growing cycle with four fungicides, three herbicides, one insecticide and one chemical to control molluscs. They buy seed that has been precoated with chemicals against insects. They spray the land with weedkiller before planting, and again after.

They apply chemical growth regulators that change the balance of plant hormones to control the height and strength of the grain’s stem. They spray against aphids and mildew. And then they often spray again just before harvesting with the herbicide glyphosate to desiccate the crop, which saves them the energy costs of mechanical drying.

Most farmers around the world, whatever the crop, will turn to one of just six companies that dominate the market to buy all these agrochemicals and their seeds. The concentration of power over primary agriculture in such a small number of corporations, and their ability both to set prices and determine the varieties available, has already been a cause of concern among farmers. Yet by next year the competition is likely to shrink even further”.

Independent advice in the UK is not as easy to get as it once was.  The expected career outcome for my undergraduate course was either academia or to work as an advisor for the then, government funded, Agricultural Development and Advisory Service (ADAS).  ADAS was the research and advisory arm of the then Ministry of Agriculture Fisheries and Food and employed specialist advisers throughout the country to advise farmers and growers how to maximise their output.   ADAS became an agency in 1992, was privatised in 1997 and in December 2016 was taken over by RSK, a large environmental consultancy.  The first incarnation of ADAS was relatively well-staffed with truly independent advisors. The second incarnation, although still billed as independent, had far fewer offices and far fewer staff, so their traditional advisory role was largely taken over by private agronomists whose agendas and training are very varied.  This state of affairs is not unique to the UK.

As an example, this is from another of my correspondents who is also on the Editorial Board of Annals of Applied BiologyThanks for your message and interesting question.  You are correct that in the US the extension service is closely aligned with the land grant Universities.  It was the complete opposite in Australia and NZ (similar to the UK) where the government funded extension service had been cut years ago and the gap had been ‘filled’ by private consultants which were also often chemical sales representatives.

Even in the USA, traditionally very strong when it comes to entomology in universities, the situation is less than rosy as this email from another correspondent (of necessity anonymised) highlights:

“I am currently the only trained entomologist in any XX university with a position focused on commercial ornamental entomology despite nurseries in XX being our largest plant-based agricultural commodity. Between shipping out 75-80% of the nursery plants across a state or international border, thousands of cultivated varieties, several planting systems (protected and field grown), and the aesthetic thresholds with ornamental plants, I’m a bit too popular (couldn’t haven’t happened in high school when I could have used it). I don’t even have a PhD and my position is actually a regional Extension educator position versus specialist. Since we have no specialists for non-food crops, I often am asked to work off position description on other ornamental plant needs in landscapes as well. Not just entomology as this is an IPM position.  This level of demand has curtailed my ability to be involved with activities that would have been useful professionally (like publishing more and reviewing work of peers). No regrets about the new discoveries, adoption and impact of my work in many diverse areas but I will have less legacy in the published world.  

I’m retiring in less than three years. A little early but necessary as I’ve been fighting burn-out for years. And the university has taught me many times that they value my work less as a female (the stories I could tell). Women in STEM gets lots of verbiage but those of us working in these systems will tell you how far we have to go yet to be treated equitably. Perhaps they will value my work once I’m gone and people have nowhere to go. I have been fortunate to have had the privilege of excellent training and only hope that this country can maintain some of these bastions of entomology into the future”

Science is crucial to the development of IPM, be it understanding pest phenology, developing and evaluating biocontrol agents or obtaining a basic understanding of the biology and ecology of a particular pest (e.g. Webb et al., 2015; Dandurand & Knudsen, 2016; Karley et al., 2016; Rowley et al. 2016).  Basic science is important, but funding needs to be mainly allocated to more immediately applicable research than to the more academic end of the spectrum which is where it tends to go more often than not (Hokkanen, 2015).   I recently attended a conference organised by AgriNet, http://www.agri-net.net/ whose mission statement is “AGRI-net is an Agri-science Chemical Biology network which aims to stimulate the development and facilitate the translation of novel tools and technologies to key end-users in the Agri-sciences”, the title of which was  Bridging the gap between Physical sciences & Agri-sciences research.  Although the science presented was excellent it was hard to see how it could be translated to the relevant end-users in their lifetimes.

Don’t get me wrong, basic science is needed as there will be a time when the technology is available for it to be relevant.  As an example, Winer et al. (2001) convincingly demonstrated that planting spring wheat at extremely high densities (up to 600 seeds m2) in a grid pattern, significantly reduced weed density and significantly increased yield when compared with planting at conventional seed rates and in the traditional row pattern.  Fifteen years ago this may not have been very attractive to farmers as it would have meant modifying their already expensive machinery.  With the advent of precision farming this is perhaps now a viable strategy, but so far is little taken up by growers.  Is this a lack of communication from the scientists to the end-user or a reluctance to adapt new ways by the farmer?  I would suggest the former.

The recent State of Nature report (Hayhow et al., 2016) caused dismay amongst UK ecologists and raised the hackles of the UK farming community.  The data were very convincing and much of the decline in wildlife in agricultural systems was attributed to the intensification of agriculture post World War 2. The UK farming community reacted quickly and angrily (Midgely, 2016), pointing out that farming practices have changed greatly over the last half century and that the report was overlooking the many farmers who have willing engaged with the various environmental stewardship initiatives.  The debate was somewhat exacerbated by the fact that some trenchant exchanges on both sides of the fence are of a long-standing nature.  Although I have a great deal of sympathy for the conservation side of the argument I sometimes feel that the language used by what the farming press equally dismissively calls ‘green lobby’ does not help. Michael McCarthy for example, an author whom I greatly admire, is in his recent book, The Moth Snowstorm, is extremely scathing about the practices of farmers, whom he mockingly calls “Farmer Giles” (McCarthy, 2016)

Similarly, there has been for some time, a debate within the scientific community as to whether it is better to farm intensively to maximize yields while conserving and protecting natural habitats (land sparing), or to use wildlife-friendly farming methods (land sharing) that integrate biodiversity conservation with food production (e.g. Tscharntke et al., 2012; Bommarco et al., 2013; Fischer et al., 2014; Kremen, 2015).  Due, however, to the pressures imposed by academic institutions and state funding bodies, the scientists concerned publish in ‘high impact’ conservation journals unlikely to be read by agronomists let alone farmers.

Sue Hartley (2016) “…working in Malawi on a Christian Aid funded project on improving crop resilience to drought.  I thought I had the answer: farmers should stop growing maize and grow the much more drought tolerant millet instead.  Consternation amongst the farmers greeted that suggestion! “But, they exclaimed in horror, Dr Sue, we can’t we are married to maize!  Hopelessly naïve, I had neglected the wider cultural and socioeconomic context; I’d focussed on the physiology of the plants, my discipline, and not on the sociology of farmer behaviour, someone else’s discipline

There are ways to bridge the gap, although it may mean some scientists having to step outside their laboratories and comfort zones. A recent experiment in China where academic staff and their postgraduate students lived in farming communities and worked alongside local farmers resulted in significant increases in crop yields (Zhang et al., 2016).  Whilst not suggesting that all scientists involved in basic science with potential agricultural applications, adopt a similar approach, I would encourage them to spend some time speaking to farmers on their farms and not in workshops away from the agricultural environment.   Similarly, I would exhort ecologists with an interest in agriculture to either publish in journals more likely to be read by agronomists and farmers and not in journals that only their peers will read. Arguments in journals such as Biological Conservation, no matter how well presented or reasoned, reach a very limited audience of peers and undergraduates writing assignments. The people who make the decisions and grow our food do not read those journals. Failing that, in these days of ‘research impact’ it would make sense to take steps to summarise their findings in a more popular format such as the farming press. The workshops often mentioned in grant applications under the “pathways to impact” section will only have a limited reach and the proposed web sites, another favourite of the grant writer, unless extensively advertised and scrupulously kept up to date, again will remain largely unread.

Most importantly, use language that everyone can understand.  The farmer representing Innovate UK at the Agri-futures meeting was particularly scathing about the presentations, slickly and smoothly delivered by the obviously keen and excited scientists, remarking that most farmers would not know the word heterogeneity; keep it simple, avoid jargon, but don’t speak down to practitioners just because they don’t have the same vocabulary you do.   Emma Hamer the Senior Plant Health advisor for the National Farmers Union was just one of the many speakers from industry at the Advances in Integrated Pest Management Conference that I attended in November, who pointed out that many farmers were still unaware of exactly IPM was, even though they were practicing it to some extent.

There are agricultural scientists who do their best to step down from their ivory towers and try to make their work easily accessible.  Rothamsted Research for example, where the scientists are under immense pressure to publish in high impact journals, are doing their best to provide an effective extension service despite the swingeing cuts that have been made to their staff who work with whole organisms.  Their advocacy of the IPM concept via their app Croprotect is innovative and useful.  The UK of course is not alone in these types of ventures.  My Editorial sparked this response via email:  “I read with interest your editorial in the Annals of Applied Biology.  Our research group works strongly with State Government to convert our research into practical tools for fire management, but we struggle at the interface because each agency things that it is the responsibility of the other to do the extension work!  A better example comes from my colleagues in the crop sciences who have a very workable model in the southern hemisphere (see http://www.apen.org.au/extensionnet ).” On the other hand, we have scientists who extol the virtues of extension but publish in journals that are non-accessible to many academics and certainly beyond the ken of agronomists and farmers (Kremen, 2015).  Important commentaries on pollinators aimed at farmers and politicians (Dicks et al., 2016) are too often hidden behind ‘high impact’ paywalls and if not revealed by helpful bloggers such as Jeff Ollerton, would remain hidden away from the very people who need to know.  Other bloggers such as Manu Saunders are also on the case, debunking and/or publicising the debates surrounding sustainable agriculture, but this is not enough.  Scientists who put themselves forward as working in the agricultural sciences need to pay more heed to the ways in which farmers work, understand the farming year* and actually talk to farmers whilst in their own environment.  Perhaps not so much as being on the same page but standing in the same field.


Pleased to see that a Wordle analysis of this post puts farmers centre stage.



Bommarco, R., Kleijn, D. & Potts, S.G. (2013) Ecological intensification: harnessing ecosystem services for food security. Trends in Ecology and Evolution, 28, 230–238

Dandurand, L.M. & Knudsen, G.R. (2016) Effect of the trap crop Solanum sisymbriifolium and two biocontrol fungi on reproduction of the potato cyst nematode, Globodera pallida. Annals of Applied Biology, 169, 180-189

De Fluiter, H.J. (1962) Integrated control of pests in orchards. Entomophaga, 7, 199-206.

Dicks, L.V., Viana, B., Bommarco, R., Brosi, B., del Coro Arizmendi, M., Cunningham, S.A., Galetto, L., Hill, R.,  Lopes, A.V., Pires, C., Taki, H., & Potts, S.G. (2016) Ten policies for pollinators.  Science, 354, 975-976.

Fischer, J., Abson, D.J., Butsic, V., Chappell, M.J., Ekroos, J., Hanspach, J., Kuemmerle, T., Smith, H.G. & von Wehrden, H. (2014) Land sparing versus land sharing: moving forward. Conservation Letters, 7, 149–157

Hammond, C.M., Luschei, E.C., Boerboom, C.M. & Nowak, P.J. (2006) Adoption of integrated pest management tactics by Wisconsin farmers.  Weed Technology, 20, 756-767

Hartley, S. (2016) In praise of interdisciplinarity.  The Bulletin, 47, 5-6.

Hayhow, D.B., Burns, F., Eaton, M.A., Al Fulaij, N., August, T.A., Babey, L., Bacon, L., Bingham, C., Boswell, J., Boughey, K.L., Brereton, T., Brookman, E., Brooks, D.R., Bullock, D.J., Burke, O., Collis, M., Corbet, L., Cornish, N., De Massimi, S., Densham, J., Dunn, E., Elliott, S., Gent, T., Godber, J., Hamilton, S., Havery, S., Hawkins, S., Henney, J., Holmes, K., Hutchinson, N., Isaac, N.J.B., Johns, D., Macadam, C.R., Mathews, F., Nicolet, P., Noble, D.G., Outhwaite, C.L., Powney, G.D., Richardson, P., Roy, D.B., Sims, D., Smart, S., Stevenson, K., Stroud, R.A., Walker, K.J., Webb, J.R., Webb, T.J., Wynde, R. and Gregory, R.D. (2016) State of Nature 2016. The State of Nature partnership.

Hokkanen, H.M.T. (2015) Integrated pest management at the crossroads: science, politics or business (as usual)?  Arthropod-Plant Interactions, 9, 543-545

Karley, A.J., Mitchell, C., Brookes, C., McNicol, J., O’Neill, T., Roberts, H., Graham, J. & Johnson, S.N. (2016) Exploiting physical defence traits for crop protection: leaf trichomes of Rubus idaeus have deterrent effects on spider mites but not aphids.  Annals of Applied Biology, 168, 159-172

Kogan, M. (1998) Integrated pest management: historical perspectives and contemporary developments.  Annual Review of Entomology, 43, 243-270

Kremen C. (2015) Reframing the land-sparing/land-sharing debate for biodiversity conservation. Annals of the New York Academy of Sciences, 1355, 52–76.

McCarthy, M. (2016) The Moth Snowstorm, Hodder & Stoughton, London.

Midgely, O. (2016) Industry’s work overlooked by UK green lobby. Farmer’s Guardian, September 16, 2

Rowley, C., Cherrill, A., Leather, S., Nicholls, C., Ellis, S. & Pope, T. (2016) A review of the biology, ecology and control of saddle gall midge, Haplodiplosis marginata (Diptera: Cecidomyiidae) with a focus on phenological forecasting.  Annals of Applied Biology, 169, 167-179

Stern, V.M., Smith, R.F., Van Den Bosch, R., & Hagen, K.S. (1959) The integrated control concept. Hilgardia, 29, 81-101.

Tscharntke, T., Clough, Y., Wanger, T.C., Jackson, L., Motzke, I., Perfecto, I., Vandermeer, J. & Whitbread, A. (2012) Global food security, biodiversity conservation and the future of agricultural intensification. Biological Conservation, 151, 51–59

Webb, K.M., R.M. , Harveson, R.M. & West, M.S. (2015)  Evaluation of Rhizoctonia zeae as a potential biological control option for fungal root diseases of sugar beet.  Annals of Applied Biology, 167, 75-89

Winer, J., Griepentrog, H.W. & Kristensen, L. (2001) Suppression of weeds by spring wheat Triticum aestivum increases with crop density and spatial uniformity.  Journal of Applied Ecology, 38, 784-790.

Zhang, W., Cao, G., Li, X., Zhang, H., Wang, C., Liu, Q., Chen, X., Cui, Z., Shen, J., Jiang, R., Mi, G., Miao, Y., Zhang, F. & Dou, Z. (2016) Closing yield gaps in China by empowering smallholder farmers. Nature, 537, 671-674


Filed under Bugbears, Science writing, Uncategorized

Ten Papers that shook my World – Root (1973) – When more means less – crop diversity reduces pest incidence

I can’t remember when I first read this paper but judging by the record card and the state of the actual hard copy of the paper, it was probably when I was doing my PhD in the late 1970s. This paper and its companion, which was published a year earlier* (Tahvanainen & Root, 1972), have had a significant effect on the scientific understanding and development of inter-cropping as a method of crop protection worldwide. Although inter-cropping in some form or another has been around a long time, the idea that it could be used as part of an integrated pest management programme was not proven.  In this landmark study, Root compared pure stands (plots) of collards (spring greens in the UK) (Brassica olercaea) with adjacent rows of collards grown intermingled with other herbaceous plants.  His premise being that it was well documented that pest outbreaks tend to be associated with pure monocultures of crops (Pimentel, 1961; Janzen, 1970) and he wished to test the hypothesis that natural enemies were more abundant and effective in vegetationally diverse areas  than in pure monocultures, the so-called ‘enemies hypothesis’.  This idea had been around a surprisingly long time e.g. Ullyett (1947) who remarked  “where weeds occur around headlands and in hedges, they should be left for the purpose of supporting parasites and predators important in the natural control of the diamond-back moth (Plutclla maculipennis Curt)”.  A decade later, Elton (1958,) refers to this statement, explaining that “these hedge rows form a reservoir for enemies and parasites of insects and mite pests of crops”.  I am not sure what it indicates but note that many groups around the world, including mine, are still working on this both at the local (field-scale) level (e.g. Ramsden et al., 2014) and landscape level (e.g. Rusch et al., 2013; Raymond et al., 2015).

Root explained the premise of the ‘enemies hypothesis’ as follows.  Predators and parasites are more effective at controlling herbivore populations in diverse habitats or plant communities because, diverse plant communities support a diversity of herbivores with a variety of phenologies, providing a steady supply of prey for the predators.  In addition, complex environments provide prey refugia, thus allowing the prey not to be completely eradicated.  Diverse plant communities also provide a broad range of additional resources for adult natural enemies e.g. pollen and nectar.

Root ran his experiment for three years and did indeed find a significant difference in herbivore load between the pure plots and the weedy rows, the former having a greater abundance of pests (mainly aphids and flea beetles) than the latter.

Fig 1

From Root (1973)

To his disappointment (I assume), he did not find any difference in the numbers of natural enemies between the two treatments. He thus had to come up with another idea to explain his results. His ingenious explanation is encapsulated in what he termed the Resource concentration hypothesis which states that herbivores are more likely to find and stay on hosts growing in dense or nearly pure stands and that the most specialised species often reach higher relative densities in simple environments.

Fig 2

Typical modern monocultures, beans, cabbages and wheat

He hypothesised that specialist herbivores were ‘trapped’ on the crop and accumulated whilst more generalist herbivores were able to and likely to move away from the crops to other host plants.  Root added that the ‘trapping effect’ of host patches depends on several factors such as stand size and purity.

In 1968, presumably as a result of what Root was discovering, Jorma Tahvanainen (one of the many great Finnish entomologists who appeared on the scene in the 1970s -, he retired in 2004) came to Cornell to do his PhD with Richard Root. Working on the same system and in the same meadow, Tahbanainen developed two new hypotheses to explain why more diverse cropping systems have fewer pest problems than monocultures. His experiments as he too found little evidence of natural enemies having an effect. He developed two new hypotheses, one he termed Associational resistance which I reproduce below exactly as published:

A natural community, such as a meadow, can be treated as a compound system composed of smaller, component communities (Root, 1973). The arthropods associated with different plant species represent important components in terrestrial systems. The available information indicates that the biotic, structural and microclimatic complexity of natural vegetation greatly ameliorates the herbivore pressure on these individual components, and consequently, on the system as a whole. Thus, it can be said that in a compound community there exists an “associational resistance” to herbivores in addition to the resistance of individual plant species. If the complex pattern of natural vegetation is broken down by growing plants in monocultures, most of this associational resistance is lost. As a result, specialized herbivores which are adapted to overcome the resistance of a particular plant species, and against which the associational resistance is most effective, can easily exploit the simplified system. Population outbreaks of such herbivores are thus more likely to occur in monocultures where their essential resources are highly concentrated

The other, is the Chemical Interference Hypothesis, in which he postulated that reduced herbivory in diverse communities due to chemical stimuli produced by non-host plants interfering with host finding or feeding behaviour of specialist herbivores.  His experimental set-up was very simple, but very effective.

Fig 3

How to send mixed signals to specialist herbivores – reproduced from Tahvanainen & Root (1972)

In simple terms, a monoculture sends out a very strong signal, it could be olfactory, e.g. a strong bouquet of crucifer volatiles, or for other herbivores it could be visual, or a combination of the two.

Fig 4

Conventional intensive agricultural landscape sending out strong ‘signals’ to specialist herbivores

Inter-cropping increases crop diversity and changes the crop ‘signal’ to one that now ‘confuses’ specialists. Note that I am not necessarily advocating a combined crop of wheat, beans and cabbages, as harvesting would be a nightmare 😉

Fig 5


The intercrop melange effect

These two papers have had a huge influence on the theory and practice of inter-cropping and agricultural diversification, although Root (1973) has had many more citations (1393 according to Web of Science on 11th December 2015) than Tahvanainen & Root (1972) which has only had a meagre 429 citation to date.  The message coming out from the many studies that have now investigated the effect of intercropping crop diversification on pest abundance, is, that in general, polyculture is beneficial in terms of promoting biological control and that incorporating legumes into the system gives the best yield outcomes (Iverson et al,  2014).

Another take on intercropping that overcomes the potential problems of harvesting different crops from the same field, is the concept of planting different genotypes of the same species. Resistant plants tend to have fewer generalists present, although their individual yield may be reduced.  By planting a mixture of susceptible and resistant genotypes it is however, possible to have your cake and eat it, especially if it is not essential to have a single genotype crop.  This approach has been used to good effect in the production of short rotation willow coppice, where planting diverse genotypes of the same species reduces both pest and disease levels (Peacock et al., 2000, 2001).

Who would have that two simple field experiments conducted in an abandoned hay meadow outside Ithaca, New York almost fifty years ago would have such a far-reaching influence?



Elton, C. S. (1958) The Ecology of Invasions by Animals and Plants. London: Methuen & Co., Ltd. 159 pp.

Iverson, A. L., Makin, L. E., Ennis, K. K., Gonthier, D. J., Connor-Barrie, B. T., Remfret, J. L., Cardinale, B. J. &Perfecto, I. (2014). Do polycultures promote win-win or trade-offs in agricultural ecosystem services? A meta-analysis. Journal of Applied Ecology. 51, 1593-1602.

Peacock, L. & Herrick, S. (2000) Responses of the willow beetle Phratora vulgatissima to genetically and spatially diverse Salix spp. plantations. Journal of Applied Ecology, 37, 821-831.

Peacock, L., Hunter, T., Turner, H., & Brain, P. (2001) Does host genotype diversity affect the distribution of insect and disease in willow cropping systems? Journal of Applied Ecology, 38, 1070-1081

Janzen, D.H. (1970) The unexploited tropics.  Bulletin of the Ecological Society of America, 51, 4-7

Pimentel, D. (1961). Species diversity and insect population outbreaks. Annals of the Entomological Society of America, 54, 76-86.

Ramsden, M. W., Menéndez, R., Leather, S. R. & Wackers, F. (2014). Optimizing field margins for biocontrol services: the relative roles of aphid abundance, annual floral resource, and overwinter habitat in enhancing aphid natural enemies. Agriculture Ecosystems and Environment, 199, 94-104.

Raymond, L., Ortiz-Martinez, S. A. &Lavandero, B. (2015). Temporal variability of aphid biological control in contrasting landscape contexts. Biological Control , 90, 148-156.

Root, R. B. (1973). Organization of a plant-arthropod association in simple and diverse habitats: the fauna of collards. Ecological Monographs, 43, 95-124.  1393 citations

Rusch, A., Bommarco, R., Jonsson, M., Smith, H. G. &Ekbom, B. (2013). Flow and stability of natural pest control services depend on complexity and crop rotation at the landscape scale. Journal of Applied Ecology, 50, 345-354.

Tahvanainen, J. & Root, R. B. (1972). The influence of vegetational diversity on the population ecology of a specialized herbivore Phyllotreta cruciferae (Coleoptera: Chrysomelidae). Oecologia, 10, 321-346. 429 citations

Ullyett, G. C. (1947) Mortality factors in populations of Plutella maculipennis Curtis (Tineidae: Lep.) and their relation to the problem of control. Union of South Africa, Department of Agriculture and Forestry, Entomology Memoirs, 2, 77-202.

Post script

*I suspect, judging by how the two papers cite each other, that the Root (1973) paper was actually submitted first but that the vagaries of the publication system ,  meant that follow-up paper, Tahvanainen & Root (1972) appeared first.

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Filed under Entomological classics, Ten Papers That Shook My World

Underinvestment is not going to produce STARS – BBSRC take note

Earlier this year, the BBSRC at the stroke of a pen, deprived several strategically important and vulnerable research skills and capabilities areas in biosciences of approximately £9 000 000 per annum  by funneling iCASE funding to a number of universities already awash in cash and with little or no interest in vulnerable skill-sets. Now, the BBSRC in a feeble attempt to remedy this seriously misjudged action, has announced their new STARS programme. I quote from their website


“Our STARS programme aims to support the development of strategically important and vulnerable research skills and capabilities in the biosciences. Awards are available to develop postgraduate-level training in areas of significant need for clearly defined academic and industrial sectors”


Reasons for such additional support include, but are not restricted to:

A lack of training and/or capability in specific areas, or a need to up-skill individuals within a specific area

An identified need to attract researchers into the area

A need to build capacity in a new or emerging research area

A need to transfer technical and commercially relevant skills to/from industry


Delivery of training may be achieved by one or more of the following methods:

Research Experience Placements Summer research placements for undergraduate students in the middle years of their studies, to attract them into further research in a strategically important or vulnerable research area

Skills schools in strategically important and vulnerable research areas, including: Development of new skills schools

Expansion of existing institutional/regional activities for national reach

Expansion of existing activities for participation by BBSRC-funded researchers at any level (PhD, postdoctoral researcher, research fellow, research leader)

Development and delivery of training resources through other mechanisms, such as development of e-learning modules or other online resources



Up to £250k is available per year to support training activities through the STARS programme. There will be three calls per year. Awards are flexible and may be used to support strategic and vulnerable skills for a short, discrete period or for up to three years of recurrent funding.

According to the web site and after an incredulous email by me to the BBSRC, it turns out that this magnificent windfall is expected to fund 30 projects – do the sums and this averages out at just over a princely £8000 each! My colleagues and I felt (and still feel) that this really does not show a serious commitment by the BBSRC to vulnerable research skills and capabilities. Rather, it shows complete disdain and contempt for the areas that they claim to be concerned about;

“We welcome applications for support of any research capability within our remit, but particularly those highlighted in the Review of Vulnerable Skills and Capabilities, published in January 2015 (see downloads) and especially in relation to capabilities within the following areas:

Maths, statistics and computational biology

Physiology and pathology of plants, animals and microbes

Agriculture and food security”


Beggars, however, cannot be choosers and so my colleagues and I duly downloaded an application form and submitted an application to run a one-week summer school in crop protection (entomology, plant pathology, plant nematology and weed science) for three years for 15 undergraduate students per year. Notwithstanding the small sums of money available, the form required inputting a disproportionate  amount of information; asked for a business plan and detailed information, concerning in the case of a taught summer school, details of lecture content and delivery, and financial support or other from interested parties and the institution providing the service. In terms of person-hours the delivery of such a course far outweighs the paltry sum of money available; in fact the time taken to put together the application itself, if costed at FEC (full economic costs), would also eat substantially into the monies potentially available. I could borrow more from my bank as a personal loan with considerably more ease, less paperwork and probably with a considerably greater chance of success.

BBSRC you cannot be serious!


Post script

In case anyone wonders why I have chosen to illustrate this post with a photograph of a somewhat sceptical looking elderly gentleman, let me explain. The picture shows my late father, Robert Ikin Leather (1924-2007) who is a perfect example of one of the vulnerable skills set that our proposed summer school would highlight and attempt to remedy. He was a traditional agricultural plant pathologist who could go out into the field, recognise symptoms and diagnose diseases, as well as identifying them in the laboratory and conducting field research. He is no longer with us, as are the majority of people who shared his skills. Plant pathology in the UK is in dire straits as are weed science, plant nematology and to a slightly lesser extent, entomology. To reiterate my earlier point underinvestment in training and research in these areas is not the way to solve the problem.


Filed under Bugbears

Ten papers that shook my world – Way & Banks (1964) – counting aphid eggs to protect crops

The previous papers in this series (Southwood, 1961; Haukioja & Niemelä 1976; Owen & Weigert, 1976), were all ones that had an influence on my post-PhD career. This one in contrast, had a direct effect on my PhD as well as on my subsequent career, and was, I guess, greatly influential in the publication of the first book to deal with the ecology of insect overwintering (Leather, Walters & Bale, 1993). In 1964 Mike Way, one of the early proponents of Integrated Pest Management (in fact considered to be the father of UK IPM), was working on control methods for the black bean aphid, Aphis fabae.

Bean aphids

Mike had recently joined Imperial College from Rothamsted Research Station where he had been leading research on ways to reduce pesticide use by farmers and growers.   During his time at Rothamsted he had worked closely with a colleague, C.J. Banks on the black bean aphid including studies on the overwintering eggs. As they said in the introduction to their paper, published four years after their experiments; “During the British winter A. fabae survives almost exclusively in the egg stage. Egg mortality might therefore be important in affecting size of populations of this species and in predicting outbreaks”. They investigated the effects of temperature and predators on the mortality of the eggs on the primary host, spindle, Euonymus europaeus, and concluded that the levels of mortality seen would not affect the success of the aphids the following spring. By 1968 (Way & Banks, 1968) they had followed up on the idea and began to feel confident that aphid populations on field beans could be predicted from the number of eggs on the winter host; spindle bushes. The publication of this paper stimulated the setting up of a long-term collaborative project monitoring Aphis fabae eggs on spindle bushes at over 300 locations throughout England south of the River Humber, and monitoring aphid numbers in about 100 bean fields per year.   In 1977 the results were finally published (Way et al., 1977) and the highly successful black bean aphid forecasting system was born. This was further refined by using the Rothamsted aphid suction trap data (Way et al., 1981).

This was also the year that I began my PhD at the University of East Anglia, working on the bird cherry-oat aphid, Rhopalosiphum padi. In the course of my preparatory reading I came across Way & Banks (1964) just in time to set up a plot of bird cherry saplings which I monitored for the next three winters, the first winter’s work resulting in my first publication (Leather, 1980). I subsequently went on to develop the bird cherry aphid forecasting system still used in Finland today (Leather & Lehti, 1981; Leather, 1983; Kurppa, 1989).

Finnish aphid forecasts

Sadly, despite the great success of these two systems there has not been a huge take-up of the idea, although the concept has been looked at for predicting pea aphid numbers in Sweden (Bommarco & Ekbom, 1995) and rosy apple aphids in Switzerland (Graf et al., 2006). Nevertheless, for me this paper was hugely influential and resulted in me counting aphid eggs for over 30 years!


Bommarco, R. & Ekbom, B. (1995) Phenology and prediction of pea aphid infestations on pas. International Journal of Pest Management, 41, 101-113

Graf, B., Höpli, H.U., Höhn, H. and Samietz, J. (2006) Temperature effects on egg development of the rosy apple aphid and forecasting of egg hatch. Entomologia Experimentalis et applicata, 119, 207-211

Haukioja, E. & Niemela, P. (1976) Does birch defend itself actively against herbivores? Report of the Kevo Subarctic Research Station, 13, 44-47.

Kurppa, S. (1989) Predicting outbreaks of Rhopalosiphum padi in Finland. Annales Agriculturae Fenniae 28: 333-348.

Leather, S. R. (1983) Forecasting aphid outbreaks using winter egg counts: an assessment of its feasibility and an example of its application. Zeitschrift fur Angewandte Entomolgie 96: 282-287.

Leather, S. R. & Lehti, J. P. (1981) Abundance and survival of eggs of the bird cherry-oat aphid, Rhopalosiphum padi in southern Finland. Annales entomologici Fennici 47;: 125-130.

Leather, S.R., Bale, J.S., & Walters, K.F.A. (1993) The Ecology of Insect Overwintering, First edn. Cambridge University Press, Cambridge.

Owen, D.F. & Wiegert, R.G. (1976) Do consumers maximise plant fitness? Oikos, 27, 488-492.

Southwood, T.R.E. (1961) The number of species of insect associated with various trees. Journal of Animal Ecology, 30, 1-8.

Way, M.J. & Banks, C.J. (1964) Natural mortality of eggs of the black bean aphid Aphis fabae on the spindle tree, Euonymus europaeus L. Annals of Applied Biology, 54, 255-267.

Way, M. J. & Banks, C. J. (1968). Population studies on the active stages of the black bean aphid, Aphis fabae Scop., on its winter Euonymus europaeus L. Annals of Applied Biology 62, 177-197.

Way, M. J., Cammel, M. E., Taylor, L. R. &Woiwod, I., P. (1981). The use of egg counts and suction trap samples to forecast the infestation of spring sown field beansVicia faba by the black bean aphid, Aphis fabae. Annals of Applied Biology 98: 21-34.

Way, M.J., Cammell, M.E., Alford, D.V., Gould, H.J., Graham, C.W., & Lane, A. (1977) Use of forecasting in chemical control of black bean aphid, Aphis fabae Scop., on spring-sown field beans, Vicia faba L. Plant Pathology, 26, 1-7.


Post script

Michael Way died in 2011 and is greatly missed by all those who knew him well. He examined my PhD thesis, and to my delight and relief, was very complimentary about it and passed it without the need for corrections. I was greatly honoured that a decade or so later I became one of his colleagues and worked alongside him at Silwood Park. He was a very modest and self-deprecating man and never had a bad word to say about anyone. He had a remarkable career, his first paper published in 1948 dealing the effect of DDT on bees (Way & Synge, 1948) and his last paper published in 2011 dealing with ants and biological control (Seguni et al., 2011), a remarkable 63 year span. His obituary can be found here http://www.telegraph.co.uk/news/obituaries/science-obituaries/8427667/Michael-Way.html


Filed under Aphidology, Aphids, Ten Papers That Shook My World