Sex and Death in a British Orchard

It sounds like an episode from the latest TV crime drama - but in reality it’s an attempt by researchers at Warwick HRI, the horticultural research arm of the University of Warwick, to combat one of the major pests in apple and pear orchards around the world.

A hanging basket-style dispenser full of a virus known to kill the larvae of codling moth is hung in the orchard. The dispenser is designed to protect the virus from the elements while enticing the adult moths into its interior with a strong source of codling moth pheromone. The insect arrives hoping for a sexual encounter - but leaves frustrated and covered in the virus, which it then passes on to other moths in the course of successful mating. This results in direct contamination of the moth’s eggs or of the laying site.

The larvae die after eating the virus on the egg or plant surface – victims of their parents’ carnal desires!

Codling Moths cost fruit growers millions of pounds in damaged crops each year. Spraying is the common way of dealing with this pest, but the virus degrades in direct sunlight and orchards must be repeatedly treated to keep the moth in check. Warwick HRI’s device allows growers to selectively target the pest with a virus that kills its larvae without killing other beneficial insects – an approach that can be adapted to target crop pests around the world.