•
POTATO CONFERENCE
•
THE
VEGETABLE
FARMER •
JANUARY 2017
H
alf of these went on to
attend the cereals event
the following day and
both days were also lived
streamed over the internet. This
was great news for the
organisers as one of the aims
of the conference was for
AHDB to discuss how it could
work more closely with
agronomists and advisors in
terms of knowledge transfer
and communicatingwith
growers.
As AHDB Potatoes chair Fiona
Fell explained in her
introduction, “It is about
gettingmore joined up
research onto farms, including
getting researchers onto
farms.” Research shows that 89
per cent of growers use
agronomists as one of their
main sources of information.
“We recognise that’s a really
important route to technology,”
she added. As well as being
keen towork closer with
agronomists, AHDB is seeking
comments on its new strategy
document which includes
further development of the
SPot farm initiative in different
areas of the country.
Blight developments
and control
After a review of the year
from an agronomist’s
perspective by John Sarup of
SPUD Agronomy & Consultancy
Ltd, including a useful
discussion of spray
programmes for blight control,
David Cooke of the James
Hutton Institute in Dundee
provided an update on the
latest population dynamics of
this key disease of potatoes.
Sampling from across the
country, whichwould not be
possible without themany
Blight Scouts who take part in
the AHDB-backed scheme,
showed that once again,
despite a few novel genotypes
and new clones, the 6_A1
genotype of
Phytophthora
infestans
is the dominant type
found in England, alongwith
13_A2. The latter type remains
low in Scotland, although there
is a continuing trend towards a
higher proportion of novel
genotypes in the north-east of
the country inMoray and
Aberdeenshire.
Davidwarned growers
to be wary of over
reliance on fluazinam for
blight control after
33_A2, which has not
been seen for three
years, was identified in
an outbreak near
Peterborough this year.
“We hear some reports
of fairly intensive
fluazinam use, and it is
important to follow
FRAG-UK guidance to
prevent resistance,” he
said.
David also presented
the latest international
data from the Euroblight
initiative, which shows
that that some new
clones, such as 37_A2
are not unique to the
UK, but were also identified in
2015 in the Netherlands and
Belgium in both tubers and on
foliage. In general the
European blight population is
dominated by clonal types,
with inoculum surviving from
one season to the next on
infected tubers.
For 60 years now,
Smith Periods, which
were first developed by
L.P. Smith in 1956, as an
improvement on the
previously used system of
Beaumont Criteria, have
been themain
forecasting tool for
predicting the threat of
late blight infection. As
understanding of the
genetics of
P. infestans
and crop physiology has
improved a number of
people have looked to
see if the system could
be improved, especially
as outbreaks have been
reported in recent years
evenwhen no Smith
Periodwas recorded
locally.
PhD student Siobhán Roísín
Dancey presented the results of
her AHDB-funded research at
the James Hutton Institute. This
examined the relationships
between reported outbreaks
and recorded Smith Periods.
After conducting and testing a
series of environmental
experiments to determine new
thresholds whichwould be
indicative of high blight risk, a
new system has been
developed.
“Previously the collective
reasoningwas that a lowering
of the temperature threshold
would provide earlier indication
of blight pressure, and certainly
some systems out there
adjusted their operating criteria
in line with this in efforts to
improve the services available
to growers,” saidMs Dancey.
“While our data did
demonstrate some
improvement with this
approach, it was not a
pronounced effect, and in fact
a reduction in the period of
relative humidity at 90 per cent
or above down to six hours
from the present eleven, proved
themost strikingmatch for
those conditions which resulted
in an actual blight outbreak.”
Testing the findings against
2,000 historic reports of potato
late blight outbreaks, the
Hutton Criteria demonstrated a
significant overall improvement
in performance compared to
the Smith Period. “Past records
revealed that the Smith Period
was not performing equally
well in all parts of the country,
and the Hutton Criteria has
eliminated this issue,” she
added. The new systemwill be
available to growers next
season via the AHDB’s Fight
Against Blight (FAB) alert
service.
Potato Cyst Nematode
After late blight, potato cyst
nematode (PCN) is one of the
most challenging crop
protection issues for growers.
Matthew Back of Harper Adams
University presented data that
showed that since 2000, the
UK population has swung
towards a dominance of
Globodera pallida
populations,
which now appears in 89 per
cent of samples, while pure
populations of
G. rostochiensis
andmixed populations of the
two species have declined from
a third of populations 16 years
ago, to just 11 per cent today.
This shift has been down to
management decisions,
including the use of susceptible
20
NEW POTATO CONFERENCE FORMAT
PROVES POPULAR
The decision by AHDB to combine its annual Agronomists
Conference for potatoes with the event for cereals and
oilseeds appears to have been popular, with almost 100
people attending the first day focused, whichwas
focused on potatoes.
by Richard Crowhurst
David Cooke of the James Hutton Institute.
Siobhán Dancey has developed a new blight
predictionmodel.
