Hyperparasitoids and how to stop them

Hyperparasiet
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Hyperparasitoids and how to stop them

News

A hyperparasitoid is a parasitoid whose host is also a parasitoid. NIOO-researcher Martine Kos and her former colleague Roxina Soler have been doing research into ways to protect crops against these harmful insects.

Not all parasites are bad news. In fact, parasites can be very useful for biological pest control. Many organic sweet pepper growers, for instance, use tiny parasitoid wasps to target aphid infestations.

There's just one problem: these wasps attract other parasitoids that infect them in turn. Of these 'hyperparasitoids', two of the most notorious are Dendrocerus aphidum and Asaphes vulgaris.

They tend to strike early in the season when crops are vulnerable, increasing the risk of serious damage.  And so growers often have no other choice except to resort to using chemical pesticides.

Researcher Martine Kos

Attractants

NIOO and Koppert Biological Systems launched a new research project last in October of last year, funded by the technology foundation STW, with the aim of finding out more about the lifecycle and behaviour of hyperparasitoids.

NIOO-researcher Martine Kos and her former colleague Roxina Soler  - who's now at Koppert - are hoping the project will point the way to new strategies for protecting sweet peppers and other crops.

An approach that shows promise is the use of attractants: strong plant and insect smells that can lure hyperparasitoids - which have an extremely sensitive sense of smell - away from vulnerable crops.

Which scent?

The researchers are still in the process of establishing which scents are the strongest and the most effective: a question they describe as 'complex'.

Nevertheless, Martine Kos says she hopes that by 2019, when the research project is due to end, the industry will have plenty of such powerful attractants at its disposal as weapons to stop hyperparasitoids.

More about Martine Kos' and Roxina Soler's research in the October 2016 issue of Koppert Biological Systems' publication 'Biojournaal'. Read it online here (in Dutch)