| Arable
Farm trials support efficacy of ferric phosphate
On-farm field trials, carried out to raise awareness of pesticides in water, have highlighted the efficacy of ferric
phosphate as a viable alternative to managing slug populations.
elly Hewson-Fisher, catchment
advisor at Anglian Water, began
the trials in the Louth Canal
area in Lincolnshire – an
important drinking water source
for the county - just over one
year ago, and she has since been raising
awareness of the trial results.
“When I started with Anglian Water 18
months ago, there were no surface water
catchment management trials being carried out
in Lincolnshire.
“Awareness of sustainable metaldehyde
usage was growing, but farmers still had
concerns about the available alternatives,”
explains Mrs Hewson-Fisher.
It was soon established that a major barrier
to using ferric phosphate pellets, was the lack
of knowledge surrounding efficacy.
This triggered the decision to undertake a
very simple trial that would investigate overall
slug control strategies, and close the
knowledge gap.
“Over the past year at numerous
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collaborative events, I’ve been able to stand up
in front of farmers and say with confidence that
I was involved in the trial and monitored slug
levels myself. I know how and why ferric
phosphate works, and have seen first-hand the
results in the field,” she says.
Three farms took part in the trials and all had
similar soil types, which were under-drained.
This was a key factor, given 90% of the
metaldehyde can be lost through field drainage
systems.
Three fields of winter oilseed rape, across
the three farms, were put to the test. In field
one, half of the field was treated with
metaldehyde pellets, and the other with Derrex,
ferric phosphate pellets.
Field two was treated with the same 50:50
split, but with metaldehyde and Sluxx, ferric
phosphate pellets.
The third field was not treated with pellets,
but cultural controls such as drilling and rolling
were used to consolidate the seedbed and
reduce slug movements.
“The farmers each made their own decision
about timing and frequency of application,”
explains Mrs Hewson-Fisher.
“Slug activity was then monitored using slug
traps and we presented our findings back to
the farmers.
“I also looked at ten, 1m2 plots to assess
plant damage. This was a useful way to gather
data on the differences between ferric
phosphate pellets and metaldehyde. The
results provided valuable evidence of the
efficacy of ferric phosphate for Anglian Water’s
own knowledge, and for us to be able to share
with the wider agricultural community.
“We saw for ourselves that plant numbers
were comparable in both treated fields, and
there was no considerable variation in efficacy.
Through this we’ve driven a huge amount of
awareness.
“It’s rewarding to be able to work with the
farming community in this way, and share
valuable information that will help them to make
informed decisions in the future.”
Survey identifies extent of oilseed rape losses
this autumn
Establishing oilseed rape crops this
autumn has been challenging;
particularly in eastern counties where
dry conditions have hampered
germination and early growth and
attack from flea beetle.
he AICC (Association of
Independent Crop Consultants)
has conducted a survey
amongst their members to
ascertain the extent of damage
to OSR crops this autumn.
Agronomists were asked to record the
percentage of the crop under their control that
had been written off as a result of dry
conditions or flea beetle attack.
Over 70 AICC agronomists based in the
eastern counties stretching from
Northumberland to Kent, representing over
77,000 ha’s of OSR responded to the survey.
Dry weather takes its toll
The survey identified a particular problem in
five key counties where crop loss due to dry
conditions represented over 10% of the
cropped area. Hertfordshire and Essex were
particularly badly hit with losses averaging
45%. Bedfordshire recorded 26% loss,
Northants 19% and Suffolk 11%.
Cambridgeshire, Kent and West Sussex all
recorded 10% losses.
The most severe losses were recorded from
the counties in the south and east, namely
Northants, Beds, Essex, Cambridgeshire,
Suffolk, Herts and Kent where 9% of the crop in
total has been written off due to lack of
moisture.
Flea beetle losses too
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Flea beetle damage was less severe but no
less important in Hertfordshire (33%) and
Bedfordshire (29%). In Essex 16% of the crop
has been written off due to flea beetle damage.
Cambridgeshire and Northants recorded 12%
lost and in Hampshire and Oxfordshire losses
were recorded at around 10%.
Overall the most flea beetle damage
occurred in the counties of Hertfordshire and
Bedfordshire, where 7% of the OSR crop has
been written off as a result of the pest.
Overall, it is estimated that as many as
40,000ha’s of OSR crops this autumn have
been lost as a result of poor germination and
crop establishment due to dry seedbeds and a
further 30,000 ha’s lost due to flea beetle
damage.
Andrew Blazey of Prime Agriculture that
covers the whole of East Anglia, notes that
choosing a replacement crop for failed OSR is
not easy. “It has been a tricky balancing act
weighing up the need to maintain first wheats in
the rotation, the combine capacity for the next
harvest, how regularly pulses have been grown
in the past, the soil type of the farm and the
need to maximise profitability. The result being
that no one crop has suited all situations, and
must be looked at on an individual field and
farm basis.”
November 2016 | Farming Monthly | 15