Crop Nutrition

Biorationals in the mainstream for ornamentals

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Libby Rowland, Horticulture Crop Manager, Certis Belchim UK

07 September 2023, UK: The benefits of biological and biorational[1] products in helping to reduce the usage of chemical active substances for the control of pests and diseases in many crops are now well established, especially in protected cropping situations. Legislation already limits the permitted number of crop protection products and the Maximum Residue Levels (MRLs) found in produce, for the safety of workers and consumers. It is true that many retailers impose their own more stringent requirements but, with the obvious exception of edible plants such as potted herbs, the legislation has not, to date, been applied to ornamentals production.

New regulations for ornamentals?

There are increasing concerns in the industry that a large number of European retailers are currently looking into the possibility of introducing MRLs and pre-harvest periods as “good agricultural practice” in ornamentals production as well as for edible crops. This would be likely to apply to container-grown pot and bedding plants and, where perhaps the greatest impact might be felt, to the cut flower segment. It would potentially include the number of crop protection product residues permitted as well as the levels of residues and could also involve handling restrictions that would seriously affect the way growers work with the crop during the production cycle and at harvest, in terms of the exposure of workers/operators to the products used.

Under European regulations all crop protection products are subject to a set of “Transfer Coefficient Values” (CTVs), as a mitigation measure against transfer of active substances from a crop to the skin and the possible associated risks. Both synthetic chemistry and biological products will be bound by the same standards for dermal absorption and handling period restrictions and all manufacturers and their products face the same requirements.  It is of concern that we could see significant differences between the EU and the British regulatory frameworks, potentially putting British production in a disadvantageous position as the market becomes less attractive to manufacturers. It is therefore to be hoped that, if Europe is already looking to implement these changes, the British regulatory authorities will impose a similar system in the UK.

Growing For The Future

Certis Belchim has been working in the fresh produce sector for over 10 years, particularly in southern Europe, on its project, “Growing for the Future” (G4TF), with a target of growing residue-free produce to meet the demands of European retailers and consumers. Its focus has been sustainability, innovation and food security, initially covering protected crops such as tomatoes, peppers and cucurbits. The programmes have now been extended successfully to a wide range of crops, both indoor and outdoor, including vegetables, fruit trees, vineyards, citrus and olives. If new regulations relating to both residues and operator exposure are introduced, the principles of G4TF could be translated, subject to registrations, to the ornamentals sector using the skills and expertise built over the years to reduce chemical applications. The company’s portfolio of biorational products includes bioinsecticides and biofungicides, such as Botanigard, Armicarb, Delfin, Neudosan, Valcure, Trisoil, Iroxx, etc., registered in ornamentals, that can provide excellent residue-free control of pests and diseases, including soil diseases, in ornamental crops. Through programmes that lower the number of chemical compounds and increase the use of Biorational compounds, in combination with beneficial insects and good agriculture practice, Growing for the Future will support the ornamentals sector to enhance sustainability and biodiversity and reduce environmental impact.

Biorationals as a foundation

With the demise of the number of active substances available to the industry, biopesticides and biorationals are increasingly becoming the mainstream of crop protection programmes in ornamentals. A clear advantage is that they have no residues so, whether new regulations are implemented now or sometime in the future, they will always have a place in crop protection programmes, and it seems likely that growers will start to rely on them as the foundation of their spray programmes rather than as an added benefit for use close to harvest.

Semo Kurtev, Zest crop consultant (Zest-Sustainable ICM), is convinced that crop protection planning will become far more biopesticide-driven in the future:

“Integrated Pest Management programme planning in ornamentals usually involves multiple strategies incorporating physical controls like netting, mass trapping with sticky traps, etc. followed by biocontrols, soft chemistry and ultimately chemical products only as a last resort. Whatever the future of the regulatory system looks like, Biorationals offer a foundation on which programmes can be built.”

A UK perspective

Differences in the ornamental crops industry between the UK and other European countries, are likely to imply a greater challenge for UK growers, particularly relating to handling of the crop, if these new regulations are implemented. The diversity of production found on individual enterprises in the UK has resulted in cropping, picking and handling being mainly done manually, whereas, for example, the monoculture of their Dutch counterparts makes for greater use of technology, robots and mechanisation. At the heart of horticulture, the Dutch system is surely a step ahead and, with a lot of pressure on the supply of labour in the UK, new regulations may be the impetus needed to encourage earlier adoption of technology and mechanisation by UK growers. Indeed, one or two producers of outdoor cut flowers (for example, sunflowers) have already introduced mechanised harvesting, but it is certainly not widespread.

It seems that a change in approach to crop protection may also be underway:

“UK growers are already reconsidering their strategies,” confirms Semo Kurtev, “and are beginning to see biopesticides as the fundamental part of the programme around which to build their solutions. I believe we shall see more of that in the future, changing the emphasis completely right across Europe.”

Marketable value

The value of the ornamental crop is entirely dependent on its cosmetic appearance so there is zero margin for error and the plant or flower must look perfect. Any blemish anywhere on the foliage, flower or bud, renders the product effectively unsaleable so effective pest and disease control is vital.

Fortunately, more and more biopesticides are becoming available. The fact that some are very much host specific does create something of a challenge. Whereas effective control relying on synthetic chemistry might use only two or three products, with biopesticides alone six or seven could be required. The use of such a high intensity of products in a protected environment to achieve perfection in the crop may seem slightly illogical, but the use of targeted products does also mean no detrimental effects on non-target organisms. An important benefit of building the crop protection programme based on biopesticides rather than adding them in close to crop harvest, is that they can be integrated with macrobiologicals, protecting invertebrates such as ladybirds, parasitic wasps, predatory mites, etc., and good control can be achieved with limited use of conventional chemistry. It is important in some cases for the pest to be present in the crop for the biocontrol to work so timing is critical and understanding of the dynamics between the interaction of the biopesticide and the other biocontrol strategies, the pest vs predators, is crucial.

Potential impact

In terms of the possible implementation of new regulations, the cut flower sector is the area of greatest concern. All registered crop protection products are currently screened in exactly the same way but, as biocontrols have no residues, their use removes the risk of residues in the output going to retailers. However, there may still be issues to be addressed in terms of manual picking, handling and possible exposure to the natural substances occurring in the biorational products used due to potential re-entry intervals or crop handling intervals.

Undoubtedly as the two regulatory frameworks grow further apart in time between EU and Great Britain, the crop production methods are likely to see fast-paced changes in the near future with the implementation of automation and robotics. This will ultimately have an impact on the crop protection strategies adopted by growers in which biorationals have a certain place already and the expertise established in the G4TF project may prove invaluable to the ornamentals sector.

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