| Arable
New cases of lettuce Fusarium wilt confirmed
New outbreaks of lettuce Fusarium wilt have been confirmed at sites in Lancashire and Ireland, with a further case
identified in Cambridgeshire this summer.
o prevent further spread of the
disease, growers are reminded
to implement good crop
hygiene and seek early
diagnosis where cases are
suspected.
First identified in the UK in October 2017,
these latest cases confirm the spread of the
potentially devastating disease. All have been
identified in protected lettuce crops, which are
grown in greenhouses.
Trials are currently underway at University of
Warwick as part of AHDB Horticulture’s
SCEPTREplus project to test the impact of plant
protection products on the disease. New
AHDB-funded work will start this autumn to find
out more about the biology of lettuce Fusarium
wilt.
Lettuce and baby leaf salad production was
valued at £171 million in the UK in 2017.
Kim Parker, Crop Protection Scientist, AHDB,
said: “The effective use of techniques to detect
T
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the strain of the disease identified in the UK –
lettuce Fusarium wilt race 4 – in samples has
provided the opportunity for prompt disease
diagnosis. This has enabled affected growers
to implement measures to minimise disease
spread.”
The University of Warwick has used
conventional and molecular techniques as part
of work to detect presence of the disease.
Dr John Clarkson, who leads the AHDB-
funded research on the disease, explained:
“Lettuce Fusarium wilt is a soil-borne disease
that can survive in soil for several years, so
rigorous hygiene is essential to prevent disease
spread between crops, glasshouses, nurseries
and plant propagators.”
Guidelines and recommendations
• Review hygiene procedures across your
business
• Where possible restrict access to cropping
areas
• Seek prompt diagnosis
• Cut plants in half to check for red / brown
staining in the root
• Free diagnosis is available from University
of Warwick
• Soil should not be rotovated or spread to
other areas of the nursery if disease is
confirmed
• Infected plant material should be uprooted
and burned. Do not bury the material in soil or
add to discard piles or compost areas
• Consider leaving affected areas uncropped
or plant a non-host crop
• For protected cropping, Basamid (dazomet)
is approved for disinfestation of soil before
planting (one application in every third year)
• A technical review, summarising the current
information on the disease and potential
management strategies, as well as hygiene
guidance can be found at
horticulture.ahdb.org.uk/lettuce-fusarium-wilt-
and-root-rot.
September 2018 | Farming Monthly | 19