Integrated Pest Management (IPM) is now the norm in agriculture and horticulture. All stakeholders – national and European government agencies and public bodies, agriculture and horticulture organisations, businesses, universities and research institutes – agree with this statement. "More biodiversity and the use of resistant plants are crucial to the successful implementation of IPM", says Willem Jan de Kogel, business unit manager at Wageningen University & Research.
All stakeholders agree that we need to continue the development of crop protection based on a stepped model with a preference for prevention and biological control, and with highly targeted chemical agents only as a last resort.
In recent decades, we have developed an agricultural system which focuses on the large-scale production of high-quality food. However, by breeding and selecting crops based on taste and productivity and by implementing large-scale monoculture systems, we inadvertently made our crops more attractive and susceptible to pests and diseases. As a result, we lost part of the resilience that we see in natural biodiverse systems. Intervention with plant protection agents became essential.
Natural resilience occurs at various levels: resilient soil, resilient plants and resilient production systems in which natural enemies hold pests and diseases in check. An essential step in IPM is therefore to restore the natural resilience of crops and production systems. The basis of this resilience is biodiversity.
To restore the natural resilience in agricultural systems, we can use classical techniques such as crop rotation, mixed cropping or flowering field margins with host plants for useful insects. This enables us to restore biodiversity not only spatially (mixed cropping, field margins), but also temporally (crop rotation). At the same time, we can use advanced tools to understand and restore this natural resilience. For example, we can now map out in great detail the microbiome – the enormous set of microorganisms – in a healthy soil or in a resilient plant. If we understand what types of communities of microorganisms provide resilience in soil or plants, then we can use this knowledge to develop applications for practice, such as instruments to measure soil quality and methods to improve the resilience of soil or plants. Modern molecular biology can therefore help to restore the resilience that we unintentionally lost during the development of agriculture.
Biodiversity is also the basis for the development of biological control methods, such as using the natural enemies of harmful organisms. Well-known examples include not only predatory mites and parasitic wasps, which are being used with great success in Dutch greenhouses, but also microorganisms such as fungi, bacteria and viruses, which can form the basis for effective biological control products. The challenge is to select those microorganisms from the vast biodiversity of nature, which have the right properties to be developed into biological control agents. As part of the EU-funded BIOCOMES research project, a series of such innovative products is being developed.
Plants have an enormous diversity of genetic characteristics. Particularly interesting in the context of IPM are genes that make plants resistant to pests and diseases. But also genes involved in the plants interaction with its microbiome are interesting although we know little about them yet. These genes can be crossed into existing crop varieties with traditional breeding, but with modern molecular techniques this process is much faster and more precise. Resistant crops that are created in this way are very suitable for use in IPM.
Seeing more clearly
Molecular biology is also helping us to see more clearly regarding the diagnosis of diseases in crops. Effective diagnosticsis are a precondition for producing healthy and clean propagation material: the first step in IPM. Based on molecular techniques we can not only determine whether a disease organism is present, but also determine with increasing precision whether the organism is dead or alive, and whether it is capable of inflicting damage on a plant. For example, the fungus Fusarium oxysporum consists not only of pathogenic isolates, but also of non-pathogenic isolates or even isolates beneficial for plant health. By recognising these differences, we can avoid using plant protection products when they are not actually required.
Research into the possibilities of IPM and its further development is crucial to arrive at environmentally and economically sustainable production systems with maximum resilience. In the Netherlands, research institutions are working together with the Ministry of Economic Affairs and Dutch businesses on a series of projects within the key economic sectors (Topsectoren) Horticulture & Starting Materials and Agri & Food. These projects focus on the various aspects of IPM described above. In this way, research contributes to the continued development of IPM. This development is based on the understanding and utilisation of biodiversity.