Neonics also harmful to beneficial insects

Beneficial insects, such as biological control agents and pollinators, are also exposed to neonicotinoids. However, the potentially negative side effects of insecticides have so far mainly been reported for bees, which consume the nectar and pollen from the flowers.

Recent studies show that insect populations are rapidly declining. The researchers from the University of València and Wageningen University & Research wondered how big the role of insecticides is in this. With their study they have discovered a new route of exposure of beneficial insects to neonicotinoids.

In honeydew
The team found that the insects are exposed to neonicotinoids from a source more abundant than nectar: ​​honeydew. Insects (such as aphids, mealybugs, whiteflies and psyllids) suck plant juices from plants sprayed with neonicotinoids or treated. It now appears that the neonics also end up in the excretion (honeydew) of these insects. This honeydew is an important food source for many beneficial insects and is therefore toxic to parasitic wasps and hoverflies, for example. It leads to death within a few days.

In 2018, the European Commission decided to use 3 neonicotinoids forbid for use in open fields, because of the risks to pollinating insects such as bees. The European Food Safety Authority (EFSA) is now asking Member States and stakeholders for advice on the risk assessment of pesticides related to bees in the European Union. The mortality of beneficial insects due to exposure to neonicotinoids via honeydew has not been included in the risk assessments to date. 

New crop protection strategies
The new route of exposure deserves to be included in this review, the researchers say. "The study again underlines the need to develop new crop protection strategies that should not rely on broad spectrum insecticides (such as neonicotinoids)."

Jeanette Pennings

Jeannet has her roots in the flower bulb sector and she grew up on an agricultural company in the northern part of North Holland. As a generalist she reports for Boerenbusiness across all sectors. She is also exploring the possibilities of sponsored advertising.

j.pennings@boerenbusiness. Nl

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