| Arable
Look out for lettuce
Fusarium wilt, growers
urged
An outbreak of an aggressive disease has been reported
in UK lettuce crops for the first time and growers are
being urged to look out for symptoms to get diagnosis
early.
ettuce Fusarium
wilt has previously
been found in
mainland Europe,
but the
identification of
this strain of the disease in
Lancashire, in October this year,
was the first time it has been
confirmed in the UK.
The pathogen was identified as
Race 4, which is a particularly
aggressive strain with no known
treatments or resistant varieties
currently available.
In The Netherlands, growers are
having to move production to new,
uninfested glasshouses, or to only
grow lettuce in the winter in cooler
temperatures. Protected and field-
grown lettuce crops are worth
£142.7m* annually to the UK
economy.
John Jackson, Managing
Director at Seven Oaks Nurseries,
said: “Glasshouse lettuce growers
are extremely concerned about the
outbreak and their future as lettuce
growers. In 40 years of growing
L
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lettuce, I have never had a disease
that could not be controlled by
chemical application, soil
sterilization and environmental
control.
“If the disease spreads
significantly, we may be in a
situation, as in Holland, where
lettuce cannot be grown in the soil.
This would put many growers in a
very difficult situation, looking for
alternative crops, most of which
would need significant capital
expenditure at a time when
margins are already tight.”
AHDB Horticulture has
contracted University of Warwick
to deliver a technical review to
compile detailed information on
management options to help
minimise the impact on the UK
lettuce industry. The full report will
be published in early February
2018, but information will be
shared with industry as the review
proceeds.
Jon Knight, head of crop health
and protection at AHDB, said:
“Despite the strict rules in the UK
regarding quarantine and sourcing
of plants from other countries to
keep the probability of new threats
coming in as low as possible,
unfortunately the Fusarium wilt has
still found a way through.
“We will be collaborating with
experts in countries where the
disease is already present to
collate all relevant information
about how to prevent the disease
and what control options are
available. We will be
communicating this to the UK
industry as a matter of urgency.”
Kim Parker, crop protection
scientist at AHDB, said: “The
control of this disease is
particularly difficult as spores
survive for a long time in soil and
crop debris and there are no
effective plant protection products,
no available resistant varieties and
soil sterilisation has limited effect.
“We are therefore stressing that
avoidance is the best strategy and
urge growers to review their
hygiene measures on both the
nursery and with their plant
propagator to avoid the disease
getting on to their sites.”
Growers who suspect lettuce
Fusarium wilt in their crops should
send samples for diagnosis. As
part of an AHDB project, Dr John
Clarkson, at University of Warwick,
will accept samples for free
testing. Visit
horticulture.ahdb.org.uk/lettuce-
fusarium-wilt-and-root-rot for
further information.
An event will also be held in
Lancashire on 14 December 2017,
where ADAS Associate Plant
Pathologist Tim O’Neill wil l be
presenting on ‘Practical measures
to reduce the risk and impact of
lettuce Fusarium wilt - utilising
knowledge of other Fusarium wilt
diseases’.
To book visit:
horticulture.ahdb.org.uk/event/lett
uce-fusarium-wilt-technical-
workshop
December 2017 | Farming Monthly | 11