New strain of green peach aphid Myzus persicae needs more aggressive beneficial insects

Sweet pepper growers worldwide are battling to control a new strain of the green peach aphid Myzus persicae that presents an increasingly frequent and harmful challenge in greenhouses. Koppert has responded to the growers’ crisis by focused research on the biology and diagnosing the prevalence of the new strain in the field.

New aggressive strain of green peach aphid

Many sweet pepper growers started having serious problems with Myzus persicae in the season of 2021. Biological control agents and pesticide applications with Flonicamid were no longer controlling the aphids like they used to. It turned out that a new genotype of Myzus persicae had appeared in the greenhouses. Research by Wageningen University Research Centre showed that the pest was much less sensitive to flonicamid. ‘As a result our protocol was no longer adequate, especially with the lower temperatures in the greenhouses that resulted from the energy crisis,’ says Project Manager Radbout Timmer. ‘We realized that we were dealing with a more aggressive strain that needed a new approach and our R&D team started further research.’

Quick-fix and long-term strategies to control Myzus persicae

After thorough diagnostics of the new strain, Koppert’s R&D established two approaches: A quick fix strategy, and a long-term strategy with ongoing research and testing. ’The new strain is fast overtaking the former one and has also been found in crops such as eggplant, cabbage, chrysanthemum, roses and many others. It is establishing in the Netherlands and the UK and several other countries such as Belgium, Canada, Germany, Spain and Portugal.'

This season Koppert's researchers collected more data and experiences from the growers. ‘We discovered that Aphidius matricariae (Aphipar-M) established three times better in the crop than the traditionally released species Aphidius colemani’ (Aphipar) says Radbout. The quick fix protocol therefore focuses on Aphipar-M, which is more effective. ‘We have already proved its effectiveness in the lab, and are now doing cage and field trials to acquire hard data for recommendations for use.’

Phased protocol for biocontrol of green peach aphid

‘For the long-term solution we are not only looking at products from our portfolio but also at new candidates for the target crops. For example, our R&D team in Spain found a new parasitic wasp species that is more effective. We are also testing entomopathogenic fungi that grow on aphids and a ladybird species from which the larvae take longer than the parasitoids to establish in the crop, but can be good addition to the system. At the same time, we are looking at the side-effects of pesticides and how they fit into the protocol,’ Radbout confirms.

Faced with the green peach aphid, growers have been experimenting with a number of new pesticides for corrective control, but the interaction with biocontrol measures is mostly unknown. The compatibility of these pesticides with biocontrol agents will be researched too. ‘We will be doing side effect research with these new compounds on selected beneficials so we can solidify the protocol and recommendations for use, while being aware of the cost factor.’

‘We will communicate the first update of the sweet pepper protocol in time for the new growing season with a better strategy to tackle the new resistant strain of green peach aphid,’ Radbout confirms. ‘There is a full project team working on this urgent task.’