A hanging basket style device is at the heart of
a plan by researchers at the University of Warwick to harness the
sex drive of a major pest of fruit orchards as a weapon to spread a
virus to kill that very same pest. The device allows growers to
selectively target the pest with a virus that kills its larvae
without killing other beneficial insects.
The researchers at Warwick HRI, the horticultural research arm of
the University of Warwick, have devised a hanging basket style
dispenser full of a virus known to kill the larvae of codling moth.
The dispenser is designed to protect the virus from the elements
and also includes a strong source of codling moth pheromone. The
pheromone draws in the moth hoping for a sexual encounter and the
insect leaves frustrated but covered in the virus which it then
passes on to other moths when it does manage to have an actual
encounter with another real moth. This results in direct
contamination of eggs laid by the pest or contamination of the site
where the moth lays its eggs. The larvae are killed after eating
the virus on the egg or plant surface. This brings two key benefits
to fruit growers:
An end to spraying - Normally Growers wishing to use this form of
virus warfare have to spray almost every element of an orchard to
ensure the moths come into contact with virus. This is wasteful
both of time and resources. By this method the moth themselves
spread the virus in a very targeted way to other moths and prevents
loss of populations of other beneficial insects such as the red
spider mite which would occur if growers used pesticides.
Extended virus life - The virus does not fare well in direct
sunlight. Growers who currently spray the virus find it quickly
becomes ineffective and it has to re-sprayed several times in order
to control the pests. By placing the virus in dispensers with a
cover that shields the virus supply from direct sunlight one
application of virus could serve for an extended period and remove
the need for constant reapplication
In this Defra funded project the researchers have already tested
the effect of a single dispenser which alone infected 5% of all the
moths found over a 1 hectare site. That early test helped them
maximize the best virus formulation, and the most efficient
dispenser design that maximised access for the moths while
protecting the virus from sunlight and other elements, and the best
form of pheromone lure. That test also helped them choose between a
liquid and powder based mix for the virus - the liquid was found to
be best. The University of Warwick researchers are now working with
colleagues from East Malling Research on a larger scale 12 hectare
trial of the dispenser in a large commercial apple orchard in
Worcestershire. An array of 25 dispensers per hectare have been
erected over 3 separated orchard plots of one hectare within an
even larger orchard. The codling moth control within these three 1
hectare plots will be compared to similar sized orchard plots with
dispensers without virus, or no treatment or sprayed with a
commercial virus spray at the same virus dose.
Special note for Broadcasters: A VNR (Video
News Release) on this work with be issued via APTN at 12.15 - 12.30
GMT Tuesday 20 September - more details at:
http://www.research-tv.co.uk/
For further information contact: Dr Doreen Winstanley, Warwick
HRI,
University of Warwick tel: 024 76575076
Email:
Doreen.winstanley@warwick.ac.uk
Peter Dunn, Press and Media Relations Manager,
University of Warwick Tel: 024 76 523708
or 07767 655860 email:
p.j.dunn@warwick.ac.uk
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