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Biopesticides as an alternative to synthetic pesticides in potted plants

A new project supported by the Green Development and Demonstration Program (GUDP) will ensure greater knowledge about the effects of biopesticides and optimize their use in order to replace the synthetic pesticides used in the potted plant industry. The project will support the green transition within the entire horticultural industry, and will thus help to secure the future of potted plant production and meet the demand for pesticide-free plants.

OptiPotte will ensure more knowledge about the effect of biopesticides and optimize their use in order to replace the synthetic pesticides used in the potted plant industry. The project will support the green transition within the entire horticultural industry, and will thus help to secure the future of potted plant production and meet the demand for pesticide-free plants. Photo: Lars Kruse - AU Foto

The potted plant industry in Denmark has a production value of DKK 1.85 billion, and almost 80% of the potted plants are exported. Just like field crops potted plants in greenhouses are also attacked by various diseases and pests. And just like the farmer, greenhouse gardeners try to guard against these attacks. One of the preferred methods has been spraying with synthetic pesticides.

“But the potted plant sector, like the rest of the agricultural industry, must go through a green transition. And to do so, we need to phase the synthetic pesticides in favor of more gentle solutions. There is pressure on producers, because both Danish and foreign buyers demand pesticide-free products,” says professor and section leader Per Kudsk from the Department of Agroecology at Aarhus University.

Dansk Gartneri has adopted a strategy that synthetic pesticides must be completely phased out in the production of potted plants, and here the new project OPTIPOTTE comes at just the right time. The project will investigate and develop alternative methods to synthetic pesticides.

Biopesticides, biostimulants and basic substances

The project OPTIPOTTE will contribute to achieving the goal of phasing out the synthetic pesticides from potted plant production. The project will in fact investigate and document results with various alternative means of controlling diseases and pests that can be used not only in potted plants, but also in other horticultural crops.

“In recent years, a number of biopesticides have been approved and marketed to control diseases and pests in greenhouses. It is for example microbiological agents and agents based on naturally occurring substances such as plant extracts. They are gaining more and more ground as they are cheaper to develop than synthetic pesticides, just as they are usually gentler to useful animals and pollinators,” explains Per Kudsk, who is leading the new project.

In addition to biopesticides, there are also other solutions that can be used in greenhouses. For example, biostimulants and basic substances can have an effect.

“Biostimulants are substances that can increase the plants' natural resistance to pests. They are not classified as pesticides,” says Per Kudsk.

The basic substances have a documented effect on certain pests, but they are mostly used for other purposes in e.g., foods and therefore they are not considered to pose any risk to humans, animals or the environment.

“So, there are various alternatives to the synthetic pesticides, but in practice the effect of these agents is often unsatisfactory. This means that there is an urgent need to investigate how to optimize their effect, and whether a combination of alternatives can achieve better effects,” says Per Kudsk.

There is a great potential for the use of biopesticides in greenhouse cultures, as it is possible to control the climate and thus create optimal conditions for their effect. This is something the project OPTIPOTTE will investigate.

Five major potted plant producers

The project must work with the most relevant issues in potted plant production, and to ensure relevance, five large potted plant producers are part of the project group. They have given their take on what the biggest plant protection challenges are, so that the project can focus on the most important issues.

“Some of the biggest challenges are lice, thrips, powdery mildew and gray mold, as they occur in a very wide range of plants. Moths, fusarium and pythium also present great challenges, but they are somewhat more plant-specific,” explains Per Kudsk, who also says that OPTIPOTTE is built on the horticulture's feedback.

“In collaboration with the five horticultures, we will investigate the possibilities of transforming biopesticides and other alternative methods into real alternatives to synthetic pesticides, so that the effects necessary to produce potted plants that are both salable in Denmark and will be able to live up to the requirements for export,” says Per Kudsk.

The project runs until 2025, and during the four years the project group plans to carry out development experiments at Aarhus University's facilities in Flakkebjerg on selected combinations of cultures and pests. These experiments will subsequently be followed by demonstration activities at the participating horticultures.

Additional information

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Collaborators: Department of Agroecology at Aarhus University, HortiAdvice, A / S Knud Jepsen, Gartneriet Pedersen A / S, Rosa Danica A / S, Gartneriet Claus Christensen and Gartneriet PKM.
Funding: The project is funded by the Green Development and Demonstration Program (GUDP)
Amount granted:  DKK 4,358,792
Project period: 01.01.2022 – 31.12.2025
Contact: Professor and section leader Per Kudsk, Department of Agroecology, Aarhus University. Tel .: +45 22283382 or email: per.kudsk@agro.au.dk