…………………………………………………………………… agro-ecologie.cirad.fr

Agro-ecological crop protection Applying the principles of agro-ecology to crop protection

……………………………………………………………………………>> Crop protection lies at a crossroads

In the field of crop protection, Integrated Pest Management (IPM) has been the prevailing paradigm since the 1950s, based on a concept devised by Californian entomologists. IPM has contributed to the positive changes in crop protection since the 1950s. However, without questioning the reasoning behind the concept, it is now appropriate to wonder about the coherence between current concerns about crop protection, notably with a view to promoting the principles of agro-ecology, and current practices in the field, which often centre on using agrochemicals, in both North and South.

Agro-ecological crop protection (ACP) lies at the crossroads between several research and management concepts and fields: - agro-ecology, which can be seen as both a scientific discipline in its own right (it involves integrative studies relating to agronomy, ecology, sociology and economics, on various scales) and an agro-ecosystem management method and a social movement; - integrated pest management, which has meant pooling the efforts of researchers and practicians for the past 50 years or more, but which is now showing its limitations in the field; - biodiversity management within agro-ecosystems, which for both research and management purposes draws on conservation biology within natural ecosystems.

Agro-ecology >> Using functional biodiversity to boost agrosystem performance ………………………………………………………

Diversinervus sp., a parasitioid of Saissetia hemispherica on custard apple © A Franck/CIRAD

Agro-ecological crop protection (ACP) is an innovative, ordered approach that stems directly from applying the principles of agro-ecology to crop protection, in which ecological aspects are truly centre-stage. ACP aims to reconcile efficient crop protection against pests and diseases with the socioeconomic, ecological, environmental and sanitary sustainability of agro-ecosystems. It is also intended to make a substantial contribution to the switch from agrochemical-based practices to agro-ecological practices within cropping systems.

…………………………………………………………………… agro-ecologie.cirad.fr

>> The ecological bases of crop protection

ACP sets out to optimize ecological processes and interactions between animal and plant communities within an agro-ecosystem. Optimizing these processes, the source of bio-ecological balances in agro-ecosystems, serves to prevent or reduce the risks of bioagressor (pest, pathogen or weed) infestations or outbreaks.

Within the agro-ecological approach, maintaining (or improving) local biodiversity and maintaining (or improving) soil health are the main two ways of optimizing these bio-ecological processes and thus contributing to the ecological sustainability of the ecosystem concerned. Effective agro-ecosystem functioning, which guarantees various services (food and raw material supplies, pest and disease control, pollination or climate regulation) is ensured by the range of species that co-exist and interact within the system. Long-term crop pest management requires harmonious management of the health of both the soil and the plants within agro-ecosystems. As regards pest population management, the aim is to optimize the interactions between arthropods (pests, predators, parasitoids, pollinators) and the plant communities within which they live (cultivated or not, in- or outside the agro-ecosystem).

>> An orderly approach and a genericstrategy in the field

IPM, as we have seen, is a combination of techniques that are often still in practice based on agrochemicals. ACP, on the other hand, is an approach related to the scientific sense of agro-ecology, which requires detailed knowledge of biology and ecology and the integration of that knowledge. In practice, this agro-ecological approach takes the form of a methodical, orderly approach in which techniques are neither superimposed nor added, but considered and applied in a predetermined order, as part of a systemic rationale within which the various scales are broad (space and time scales, collective management scale).

This orderly approach makes it possible to draft a clear, generic phytosanitary strategy in the field. The first, essential stage (in chronological terms, after respecting regulatory measures, in the aim of remaining within a legal framework), before thinking about any curative techniques, concerns the priority implementation of preventive measures. Those preventive measures comprise two main categories of tactics:

- fostering soil health and growing healthyplants (examples of techniques: prophylaxis,use of appropriate varieties, crop successionsand rotations, DMC, appropriate weed control,fertilization and irrigation, organic ameliorators,etc);- increasing beneficial populations (naturalenemies, pollinators, detritus feeders,recyclers) and reducing pest populations withinand around the plot, on the farm and in theagro-ecosystem as a whole (examples oftechniques: trap crops or plants, refuge zones,crop combinations and intercropping, push-pulltechniques, plot edge management, ecologicalcompensation structures (corridors, hedges,herbaceous and flower strips, plant diversityincorporation techniques, etc).

Bee foraging on a borage flower in a flower strip added to an agro-ecosystem © C. Ajaguin Soleyen/CIRAD

…………………………………………………………………… agro-ecologie.cirad.fr

>> Sanitation, biological control throughplant community management and conservation

In this preventive, systemic approach, agro-ecological management of plant health centres on managing plant communities (crops and non-cultivated plants around plots and within the agro-ecosystem), managing other populations of living organisms, primarily arthropods but also other soil invertebrates such as worms and collembola, and other pathogens. It is widely acknowledged that diversified agro-ecosystems generally include fewer generalist or specialist pests and more beneficials.

As part of conservation biological control, managing plant communities fosters the maintenance or creation of habitats favourable to indigenous beneficials and/or unfavourable to pests.

In addition to this systemic approach, ACP also makes use of conventional techniques used in IPM, optimization of cropping practices, and plant community management methods.

Lastly, in terms of both the original rationale and actual use in the field, curative techniques are seen as a last resort, to be used only when absolutely necessary, and provided they are compatible with the functioning of the biological groups that ensure ecological services, notably pest regulation.

Within this framework, although not forbidden, synthetic pesticides will only be used as a last

resort, after other non-chemical curative techniques. The long-term future for pesticides looks bleak, given the changes in the relevant regulations and ever-greater environmental and toxicological restrictions on their use.

In line with the agro-ecological crop protection concept, sanitation, habitat management and biological control are the three key components of crop protection, within which they are entirely appropriate and effective.

Of all the different types of biological control, priority is given to conservation biological control, since it participates, both directly and naturally, in the bio-ecological balances sought. Conservation biological control comprises all the steps taken to preserve natural enemies, by preventing their destruction by other practices and boosting their efficacy, notably through habitat management.

Meeting and discussion in the field between a farmer and students © JP Deguine/CIRAD

Cirtus orchard with plant cover © JP Deguine/CIRAD

…………………………………………………………………… agro-ecologie.cirad.fr

>> Applying ACP in the field, and the keysto the agro-ecological transition

In recent years, agro-ecological progress has been made in the field of crop protection. One example is the trials conducted in Réunion, particularly on market vegetable crops (Gamour project, gamour.cirad.fr/site/) and fruit crops (Biophyto project, www.agriculture-biodiversite-oi.org/Biophyto), which are presented in other factsheets. This progress is the direct result of applying the principles of ACP in a production environment. It is also reflection of national policy on agro-ecology (Plan agroécologique pour la France) and reduction of pesticide use (Ecophyto plans 1 and 2). The success of these experiments is also the result, in terms of design and implementation, of a collective, participatory approach involving a large number of agricultural partners, led by farmers open to the agro-ecological approach. Those partners range from research to the professional sector, through experimentation, training, advisory services, teaching and transfer operations.

Other agro-ecological experiments are under way and tend to confirm the added socioeconomic and ecological value of ACP. Based on experiments in production environments, several keys to the agro-ecological transition have emerged, primarily concerning four fields of activity: research and experimentation, teaching and training, advisory and transfer services, and public incentives and support.

………………………………………………………………………………….…References CIRAD publications Deguine J.-P., Gloanec C., Laurent P., Ratnadass A., Aubertot J.-N. (eds), 2017. Agro-ecological Crop Protection. Springer Eds (in press).. Lucas P., Ratnadass A., Deguine J.-P., 2017. Moving from integrated pest management to agro-ecological crop protection. In: Deguine J.-P., Gloanec C., Laurent P., Ratnadass A., Aubertot J.-N. (eds), in press. Agro-ecological Crop Protection. Springer Eds (in press).

CIRAD factsheets - Agro-ecological management of vegetableflies in Réunion.- Agro-ecological protection of mango orchardsin Réunion. - The augmentorium.

Project websites Presentation of the CASDAR Gamour and Biophyto projects and interviews with farmers on:

- Gamour project: http://gamour.cirad.fr/site/- Biophyto project: http://www.agriculture-biodiversite-oi.org/Biophyto

Contact

Jean-Philippe Deguine, UMR PVBMT

jean-philippe.deguine@cirad.fr

Some keys to the agro-ecological transition in terms of crop protection: a shared objective with individual benefits In Deguine et al. (2016)