[Syrphidae] hoverflies in cereal fields

[Katherine Robinson]

Dear all,

As part of my PhD, I am writing a review of the effects of hoverflies on
cereal aphid populations.  I haven't been able to find any information
about what happens at low aphid densities (pre-threshold, i.e. <5 per
shoot).  In particular I would like to know:

1. At what aphid densities will hoverflies start to lay eggs in a field
(info at any scale would be useful)?
2. What aphid density is needed to sustain a hoverfly larva through
development in the field?
If you know of any publications which might be useful, or can tell me
about any unpublished data or experience, I would be very grateful.

Katherine Robinson



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Katherine Robinson			Phone:	+44 (0)1904 462039
Pest biology, modelling and management	GTN:	5129 
Central Science Laboratory		Fax:	+44 (0)1904 462111
Sand Hutton				Email:	k.robinson@csl.gov.uk
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