•
DIAMONDBACKMOTH CONTROL
•
THE
VEGETABLE
FARMER •
MARCH 2017
discussions, it was generally felt
that the best results had been
achievedwhere it had been used
as amodule drench.
In terms of biological control
options, field samples collected
at Warwick Crop Centre in 2016,
and at Kirton during the previous
large invasion in 1996 showed
high levels of parasitism by a
small wasp species, which has yet
to be identified. In addition,
laboratory studies showed good
levels of control using the fungal
product Bacillus thuringiensis
(Bt), although achieving similar
levels under field conditions can
bemore difficult.
DBM is one of three
Lepidoptera species being studied
as part of AHDB Horticulture
project FV 440. Among the aims
of the project are evaluating
different traps and the ability to
monitor traps remotely, trialling
insecticides for efficacy and
developing a risk-based decision
support system to improve
control. A discussion session
during the workshop gave those
present the chance to feedback
on the priorities for further work.
It was felt that fast cropping
salad crops under covers did not
present toomuch of a problem,
as evenwhere DBM is able to lay
eggs, the crops are generally
harvested beforemuch feeding
damage can occur. For other
brassicas however, nearly all
crops were affected to some
extent, with some reporting
varietal differences, particularly in
greenhouses. Pheromone traps
were thought to be useful, but
captures are dependent onmany
factors and there is room for
improvement. In greenhouse
crops, blue sticky traps had
provedmore successful that
other colours or pheromone
traps.
In summing up, Rosemary
Collier stressed that there is a
need for better understanding of
diamondback populations, as
well as building networks to
share data both in the UK and
across Europe. “We also need
newways to control DBM,” she
said. “This includes reconsidering
the biopesticide options and how
to get the best out of them. We
also need to look at other control
mechanisms, such as mating
disruption andwe need to talk to
CRD about the use of
pheromones to control DBM.”
14
TourmalineF1
Late150-180dayvariety.
• Veryuniformcompact heads
• Goodcold tolerance
• High level of
Xanthomonas
resistance
Spinel F1
Lateseason170-dayvariety.
• Vigorous leafy type
• Highquality, small tomediumheads
• Veryhealthywithgoodcold tolerance
+44 (0) 1472371531
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HazeraSeedsUK Ltd, J.N.R.C, Rothwell,Market Rasen,
Lincolnshire, UK. LN76DT
Hazera in theUK:
ConsistentLateSavoys
Diamondbackmoth adult [pic courtesy Rosemary Collier]
Cauliflower leaf damaged by DBM [pic courtesy Rosemary Collier]
