1. Annual Meadow Grass control in Winter
Barley Post CTU
By
Benjamin David Lowe
In partial fulfilment of the requirement for
Agriculture – BASIS

2. Executive Summary
This BASIS report examines the effectiveness of Annual Meadow Grass control within winter barley,
cropping within the South West of Scotland.
The background of biology of AMG, why grass weed control within cereal production is an issue and
what cultural, technological and chemical controls can be used within AMG management.
A trial site of AMG was set up in Northallerton to compare various chemical treatments at both pre
and post emergence.
Field scores were collected across 79 different sites within the SW region of Scotland to collect
differing treatments, seed bed quality, variety used, cultivation type and AMG control. Data was
collected and produced for this report.
All results from both the trial and field scores proved that pre emergence applications were far
superior to post emergence treatments. This demonstrates that timing of chemical applications are
essential to achieve optimum results, which has reduced the window available to maintain efficiency
of Active Ingredients.
Seed bed quality was also found to have a major influence upon AMG control, with poor seed beds
having a negative effect upon treatment efficiency, this had the same result, no matter which chemical
treatment was used.
My recommendation for a land manager within the SW of Scotland would be to use a non-selective
herbicide pre cultivation to remove any germinated AMG which would not be controlled post
establishment of the crop. A plough based system would also bury any newly germinated AMG or
any seeds left from previous cropping. Establishing the crop at an optimum time ensuring a fine firm
seed bed with seed to soil contact. Seed used should be dressed with Deter seed dressing, this will
reduce risk of BYDV being vectored onto the crop for up to 6 weeks increasing flexibility within
herbicide timings.
To achieve best possible control within a pre emergence herbicide treatment on Winter Barley, I
would recommend that Flupysulfuron – methyl, flufenacet, diflufenican and pendimethalin would
provide an optimum control upon AMG. This mix would also provide good resistance management
with 3 separate modes of action. This treatment must be made pre emergence, preferable within 36
hours of sowing with some precipitation following the application to improve efficiency.
A slightly more flexible application of flufenacet, diflufenican, pendimethalin and picolinafen would
allow applications to be made at post emergence up until GS23 of the WB crop. This would work well
at pre emergence, however control would be reduced the longer the seed bed was not applied with
herbicide after sowing as AMG would begin to establish.

3. Contents
Executive Summary................................................................................................................................2
List of Abbreviations ..............................................................................................................................5
Introduction.............................................................................................................................................6
Aims................................................................................................................................................6
Hypotheses......................................................................................................................................6
Annual meadow grass (Poa Annua)................................................................................................7
Requirement for Weed Management in UK Agriculture....................................................................7
Weed Tolerance ..............................................................................................................................8
Integrated Controls..........................................................................................................................8
Chemical Management ...................................................................................................................9
Application Method and Nozzle Choice.......................................................................................10
Environmental/Legal.............................................................................................................................12
European Water Framework Directive (EUWFD) .......................................................................12
European Drinking Water Directive 98/83/EC (DWD)................................................................12
Directive’s effects upon UK Agriculture......................................................................................12
Prevention of Actives Reaching Water.........................................................................................13
Report....................................................................................................................................................14
Weather.........................................................................................................................................14
Methodology.................................................................................................................................15
Northallerton Trial Site.................................................................................................................15
Field’s Assessments in SW Scotland............................................................................................16
Limiting Factors............................................................................................................................16
Results and Discussion .........................................................................................................................17
Northallerton AMG Trial Site...........................................................................................................17
South West of Scotland Field Assessment’s.....................................................................................19
Seed bed Quality effect on AMG..................................................................................................20
Non-Selective Herbicide Application Pre Establishment .............................................................21
Further Studies..............................................................................................................................22
Conclusion ............................................................................................................................................23
Appendix...............................................................................................................................................24
References.............................................................................................................................................25

4. Declaration
This BASIS project, and the research carried out and report within, has been carried out solely by
Benjamin Lowe.
Where other sources of information have been utilised or quoted, full reference has been provided.
..............................................................................
Benjamin David Lowe
Monday 10th
January 2015

5. List of Abbreviations
AMG Annual Meadow Grass
BLW Broad Leaf Weeds
WB Winter Barley
GS Growth Stage
CTU Chlorotoluron
IPU Isoproturon
EA Environment Agency
ESA Environmental Services Association
SEPA Scottish Environmental Protection Agency
COSHH Control of Substances Hazardous to Health
NRoSO National Register of Sprayer Operators
NSTS National Sprayer Testing Scheme
ALS Acetolactate Synthase
AHAS Acetohydroxy Acid Synthase
HRAC Herbicide Resistance Action Committee
WSSA Weed Science Society of America
BCPC British Crop Production Council
DWD Drinking Water Directive
WFD Water Framework Directive
AI Active Ingredient
PPB Part Per Billion

6. Introduction
Control of grass weeds is key to maintaining a high output rotation of mainly autumn sown cropping.
Reliance upon fewer herbicides due to the absence of new modes of action, increased herbicide
resistance and loss of herbicides under EU legislation could cost the industry in excess of £500
million (Stobart 2013). This has led to crop production techniques moving to put more focus upon
integrated approaches, using new and existing strategies to maintain control in cereals.
AMG is a major weed across the UK, with the ability to rapidly move through life cycles to produce
seed within 6 weeks, after germination. Compared to other grass weeds such as blackgrass and rye
grass, AMG has not received as much publicity.
Winter Barley remains an essential crop within UK agriculture, with 319 000 Ha being grown in 2013
(National Statistics 2013). Winter Barley is utilised within crop rotation as a key management option,
providing an early harvest window improving utilisation of resources while also allowing integrated
controls upon other pests, weeds and diseases.
Within the South West of Scotland, Winter Barley is grown within a predominantly grass rotation as a
source of cereal feed and straw within intensive livestock systems. Farms within this area are often
not set up for arable enterprises, with a strong reliance upon old equipment, shared machinery and
contractors. Due to this, essential crop operations such as herbicide, fungicide, PGR and insecticide
applications are sometimes poorly timed and/or grouped together in an attempt to reduce
costs/number of applications.
Aims
 Investigating and assessing the effectiveness of AMG control in Winter Barley sown in the
autumn of 2014.
 Compare cultural controls, chemical controls at pre establishment, pre emergence and post
emergence.
 Fully understand the reasoning why Chlorotoluron and Isoproturon have been revoked/rate
reduced within the European DWD. Assess the potential for other herbicide AIs used for
AMG control to be removed from use.
 Understand the safety considerations related for use of treatments towards environment,
operator/farmer and public who may be in contact with field and area surrounding.
 Produce an AMG control plan for Winter Barley which is reliable in a changeable climate,
safe and provides optimum control in a sustainable manner.
Hypotheses
Null-Hypothese – AMG can still be sustainably controlled within winter barley production.
Alternate-Hypothese – AMG can no longer be controlled within winter barley production.

7. Annual meadow grass (Poa Annua)
Description
Easily recognisable and present in most arable fields within the
UK, this annual loosely tufted grass is variable in size from 5 – 30
cm, the leaves are light/pale green and “boat” shaped unlike most
tapered grass leafs. Leaves are generally crinkled and hairless with
a twined “tramline” centre line up the middle of the leaf. The leaf is
folded in shoot and base of the leaf, and is absent of auricles (Bayer
2014).
AMG has the ability to germinate, grow and flower all year round.
Most plant activity is found in warm months between April to
October however can germinate throughout the year.
In optimum growing conditions AMG can complete its lifecycle within 6 weeks, producing up to 500
seeds, allowing multiple generations of the weed to be produced within one season, combined with
seed longevity of 5+ years allows a large seed bank to be built quickly. AMG can also regenerate
from shoots detached from main plant during cultivations, mainly due to the plant having long lateral
roots.
AMG’s limits yield within the early stages of
crop growth, especially in Winter Barley where
yield is set early from number of tillers produced.
High competition for light, fertiliser and water
can reduce plants and tillers numbers per m2
.
This is especially apparent in a struggling crop.
The weed can delay ripening of the crop and
cause problems during harvest operations.
Requirement for Weed Management in
UK Agriculture
A weed is a plant growing in the wrong place at
the wrong time. In crop production a weed will
compete against desired plants for space, water, fertiliser and light. This will negatively affect
performance of crop in yield and quality. The yield impact weeds cause upon a crop, depends on weed
Figure 1 AMG with seed head. Removed
from WB field 20/11/14
Figure 2 AMG Defining Features. (Geissel 2004)

8. species, density and crop. Weeds can also cause loss of efficiency of field operations during and post
harvesting. (J. C. Ilett 2014)
Due to herbicide availability declining, few new herbicide chemistry molecules are becoming
available and weeds are becoming resistant to current chemistry. Maintaining production, cultural
controls have become essential within weed management.
The industry has had a number of directives published with an aim of reducing the number of
herbicides revoked and maintain their efficacy by preventing rapid resistance building up within weed
populations. The EU Sustainable Use Directive has been a key driver encouraging a fully integrated
crop management approach. The challenge is to integrate crop cultivation methods, drilling date, crop
rotation, herbicide use, resistance management and environmental protection (Dr S.Cook 2010).
Weed Tolerance
Land managers have always demanded weed free
crops, however with many non competitive weeds,
a level of tolerance can be achieved within crop
production. This requires a different mind set and
may improve bio-diversity within a field. AMG
can have a population of 50–99 plants/m2
before a
negative effect upon the crop is seen (R M Stobart
2013). However this population could be
unsustainable as seed banks build up within the
soil, AMG could potentially have 4 generations
within a WB crop.
Crop tolerance to AMG is dependent upon GS of the crop and health. If a crop is struggling at an
early GS with little ground coverage then the potential of yield loss increases significantly.
Integrated Controls
Winter Barley cropping in itself is a cultural control, as the crop competes for space and light very
aggressively in its early stages of growth. Seed rates are generally high with conventional varieties,
with a targeted plant population of 350 m2
, this provides a higher GAI than other cereals such as
wheat within early GS20’s. Hybrid WB generally has a lower optimum plant population of 200 plants
per m2
, however hybrids have increased vigour once established and will tiller out to cover available
ground.
Rotation
Rotation has little effect upon the control of AMG unless there is a 8+ year grass ley within the
rotation. Grass leys must be well managed ensuring establishment of grass weeds is minimised, this
includes not over grazing, preventing poaching and bare land where weeds will get a foot hold.
Figure 3 Winter Barley, with AMG vigorously competing,
photo taken 19/12/14

9. Managing the Seed bank
Weed seeds generally germinate within the top 5 cm of the soil profile, seed banks can be reduced and
increased from correct timing and choice in cultivations. Seeds can be spread across fields during
harvesting operations such as combining and straw collecting/chopping (Dow 2014).
Cultivation Choice
Use of stale seed beds immediately post previous crop
being harvested is an optimum time to reduce weed seeds
within the soil profile. A stale seed bed can be achieved
by use of a shallow cultivation within the top 5 cm of soil.
This can also be achieved by an aggressive spring tine
which further reduces costs. Once weed seeds, often
including volunteer seeds from previous crop have chitted
an application of a non-selective herbicide can be made.
From an environmental point of view this technique can
reduce number of seeds available on soil surface used as
food, care should be taken to ensure that farm bio-
diversity is maintained.
Rotational ploughing has become an essential integrated
approach to weed control, this allows 95% of freshly-shed
seed to be buried below 15 cm and thus shall not
germinate (Dr S. Cook 2010). Care must be taken when
setting up plough to ensure all surface trash is effectively
buried, poor setup can lead to weed seeds being spread
throughout the entire top soil profile, causing difficult management of weed seeds emerging at
different timings. Generally a rotation of 4+ years should be adopted between ploughing, AMG
however has a seed longevity of 5+ years, meaning that a rotation of 6+ would be advisable, in the
SW of Scotland the use of long term grass lays within the rotation may aid extending time between
ploughing. Ploughing can however bring up old dormant seeds from depth, with 30% expected (Dr S.
Cook 2010).
In Deep tillage, weed seeds are generally mixed throughout the soil profile, this results in new and old
seeds being within the top 5 cm of soil profile which allows germination, some weed seeds are buried
but this is a inconsistent and uncontrollable way of burying seed.
Shallow and No till systems provide most new seeds being left within the top 5 cm of soil allowing
germination, the old seed being left at depths which reduces chance of germination. These tillage
options receive best results from stale seed beds.
Chemical Management
Historically herbicides such as IPU and CTU were
key within AMG control, before being removed. CTU
Figure 5 A spray miss, comparing the difference
between chemical control verses non-chemical.
19/12/14
Figure 4 WB on compacted headland, AMG out
competing the poor crop

10. is found in co-formulations now with diflufenican and Pendimethalin known as Tower, however at a
reduced level, use of this product is minimal. Loss of these herbicides at good rates, has resulted in the
window of optimum control being significantly reduced after GS12 (2 true leaves).
Herbicides cost up to £45/ha in winter cereal production, due to this a program which provides
optimum control and ensures a high quality and yielding crop is essential (Olivia Cooper 2013).
Chemical control is fundamental for controlling AMG , mainly due to its 5+ years seed longevity and
ability to germinate throughout the year.
Key AIs Crop Timings Mode of Action
Flufenacet Pre Emergence to GS 23 Mitosis Inhibitors
Pendimethalin Before leaf sheath erect stage Mitosis Inhibitors
Prosulfocarb Early Tillering GS 21 Fatty Acid and Lipid
Biosynthesis Inhibitors
Flupysulfuron – methyl Pre Emergence Only Acetolactate Synthase (ALS) or
Acetohydroxy Acid Synthase
(AHAS) Inhibitors
Diflufenican GS 32 Carotenoid Biosynthesis
Inhibitors
Chlorotoluron Photosystem II Inhibitor
Picolinafen GS 30 Carotenoid Biosynthesis
Inhibitors
Iodosulfuron-methyl-sodium GS 33 Acetolactate Synthase (ALS) or
Acetohydroxy Acid Synthase
(AHAS) Inhibitors
Glyphosate Pre harvest or very early pre
emergence or pre establishment
Enolpyruvyl Shikimate-3-
Phosphate (EPSP) Synthase
Inhibitors
Isoproturon Removed from use Inhibiting protein biosynthesis and
disrupting the photosynthetic
process
Application Method and Nozzle Choice
Following correct integrated controls, chemical choice and optimum timing, it is essential to ensure an
even distribution of spray on targeted area. Patchy control of AMG can often be linked to poor choice
of spray nozzles. Spray nozzles are the least expensive part of an application (Kurt Hembree 2010).
Nozzle choice directly affects spray droplet size, drift potential, uniformity and coverage. Poor
efficiency of application causes increased costs of input in the long run and potentially harmful to the
environment. The goal of any herbicide application is to deliver the herbicide and carrier to the target
area, efficiently, accurately and uniformly.
Table 1 Spray quality categories (Abstracted from Kurt Hembree 2010)
Spray Droplet Diameter (µm) Spray droplet category Example
11 – 145 Very Fine Wet fog
145 – 225 Fine Fine mist/drizzle
226 – 325 Medium Very fine rain
326 – 400 Coarse Fine rain
401 – 500 Very Coarse Light rain

11. Trials carried out by Agrovista UK, control using pre emergence applications ranged between 10% to
95+%, simply by changing nozzle choice, water volume, spray pressure and adjuvant choice,
everything else stayed the same (Agrovista 2014). Results showed that:
 Higher water volume of 300 litres/ha preformed better than both 200 and 100 litres/ha
 Variable Pressure VP80 flat fan nozzle provided better results than air inclusion
 Use of twin line rather than single provided more droplets meaning better coverage, reduced
drift and improved work rate
 Twin line allowed front nozzles to be angled forward 30 degrees with second line vertical
reducing shadowing of clods on soil profile further improving coverage.
 Interestingly 3* rated (low drift) nozzle settings provided poor efficacy
As well as selecting the correct
nozzle it is essential to have a
competent sprayer operator who
has all the information and tools
necessary to complete
applications safely and efficiently.
Up until the 26th
of November
2015 spray operators born before
the 31st
of December 1964 can
legally apply pesticides under the
grandfather rights law, however
now all users of professional
pesticides have to hold a
recognised certificate.
Under a number of quality assurance schemes, often run output consumers, sprayer operators are also
obliged to be part of the NRoSO, being part of the register required operators to collect at least 30
points over a 3 year period by undertaking training days and/or attending specialist crop protection
events. These training days are very much based upon practical use of spraying equipment, agchem
products and environmental concerns, namely avoiding non target insects such as bees and improving
water quality.
Further regulations are coming into force, as of the 26th
of November 2016, any sprayer with a
working width above 12 meters will require to pass a NSTS which is similar to a MOT for public
vehicles.
Figure 6 Spray miss within a field of WW. 19/11/14

12. Environmental/Legal
Agriculture contributes significantly to water pollution, mainly due to the industry being the largest
land use within the UK, being responsible for 50-60% of nitrate load, 20-30% of phosphate and 75%
of sediments. Pesticides have also become a focus with the WFD and DWD, both playing a major part
in current cropping systems (S. Crabbe 2014).
European Water Framework Directive (EUWFD)
In December 2003 the European WFD became law, aimed at reducing content of chemical elements
within both coastal and inland water. The EA is responsible within the UK for implementing the
EUWFD. The EA is responsible for regulating, monitoring and managing all water areas of the UK,
producing management plans for every river basin every 6 years. The EUWFD’s goals are:
 Ensuring progressive reduction’s of pollution within ground and coastal water.
 Identifying individual chemical substances within water.
 Promote and educate on sustainable use of water.
 Prevent further deterioration of aquatic ecosystems and wetland areas.
 Enhance water quality maintaining a safe and sustainable water source for all users.
European Drinking Water Directive 98/83/EC (DWD)
In the UK all drinking water, whether from public supplies or other sources, has to meet standards laid
down in the DWD (Water UK 2014). The directive monitors microbiological and chemical
parameters, this has affected agriculture as many key pesticides have been found within water. The
maximum allowable concentration for a single pesticide at the tap is 0.1 PPB and maximum allowable
concentration for total pesticides in water being 0.5 PPB. Any pesticide continuously being found
exceeding 0.1 PPB in samples will be at serious risk of control measures such as label changes or
being removed from the CRD’s register. To put this in perspective, 0.1 PPB is equivalent to 1 second
in 320 years or 1 grain of wheat in 390 tonnes (NRoSO 2015).
Directive’s effects upon UK Agriculture
Due to the European WFD and DWD crop production pesticides within agriculture have recently
come under increasing scrutiny. Naturally the AIs used most within crop production systems are the
ones found most readily within water, making their removal more difficult to replace with other often
less efficient chemistry.
In 2008 IPU was withdrawn from use within crop production, used to control AMG and BLW in
Winter Barley. As CTU was still available, there was options with similar control upon targeted
weeds. IPU is however still found in surface water within the UK.

13. Prior to 2010 CTU was used at up to 3500 g/ha within cereal production to control AMG and BLW,
however from 2010 CTU was only allowed within Co-Formulation products such as Hekla (DFF +
CTU). However by 2013 Co-Formulations had also been revoked.
Pesticides under pressure from the WFD and DWD are key actives within crop production.
Metaldehyde has received a large amount of publicity over recent years and remains at high risk of
being withdrawn. Glyphosate is also found present in water. If this active was to be revoked, the
agricultural industry would find non-selective weed control extremely difficult. A number of Grass
and/or OSR herbicides are also at risk with Propyzamide, Carbetamide, Clopyralid, Quinmerac and
Matazachlor all being recognised as at risk (NRoSO 2015)
Out of the selective herbicides currently available within WB production, Pendimethalin has been
found present in water, although in relatively low amounts, could become under threat, especially
with the ability to apply 1500 g/ha active. From history, once IPU was removed, CTU levels rose in
water due to the increased reliance within weed control, this could potentially be the case as
Pendimethalin will be used in more situations and larger doses.
Prevention of Actives Reaching Water
Prevention should always be the first solution to a problem, responsible use of pesticides could have
prevented the loss of many of the actives ingredients under legislation. Pesticides can reach water
from two main areas, the farm yard where chemicals are stored and applicators are filled or from the
field.
A foil seal from a pesticide container in a stream 1 meter wide and 30 cm deep could potentially cause
30 kilometres of the channel length to exceed the 0.1 limit emplaced by the EU DWD (NRoSO 2014).
This shows the impact from 1 piece of litter while a sprayer is filled can have effects environmentally.
Due to this, stores where high concentrated chemicals are held should be bunded with sufficient
hazard plans in place in case of a fire or spill. Sprayers should be filled on a pad which catches all
spills, preventing ease of access to a water course. Pesticide containers should be cleaned with clean
water when emptied into a sprayer as part of best practice and disposed of by a licensed company.

14. Report
Weather
As the study was aimed at South West Scotland it is essential
to understand how the climate impacts upon the agricultural
industry within this region, why mainly mixed and intensive
dairy farming have become the major land uses. Western
Scotland consists of predominantly high ground about 200
metres above sea level, due to this the majority of arable
cropping is found around coastal regions where conditions are
kinder.
Western Scotland benefits from strong maritime influences
(Gulf Stream) providing a milder climate than other north
eastern climates of the UK, this provides an annual mean
temperature of 9.4 to 9.7 0
C around coastal regions however
within highland regions can drop as low as 8 0
C (Met Office
2014).
South West
Scotland receives
high levels of
rainfall between
1000 mm to 3500 mm throughout the region, high when
compared to Eastern England’s average of 500 mm.
Rainfall within SW Scotland generally distributed
throughout the year however there are seasonal
variations with the spring and summer receiving less
rainfall (Met Office 2014).
A warm and wet climate provide favourable growing
conditions for many cereal crops and especially grass.
Diseases which favour wet conditions such as
Rhynchosporium and Ramularia require control under
high pressure. High rainfall however causes problems within field operations such as cultivations,
applications of agchem/fertilisers and harvesting, recently seen in 2012 when harvesting caused soil
structure damage, crop losses and little autumn sown crops being established. As an average over
seasons winter cereals can be effectively grown, however, notably with a reduced window to establish
winter barley. From this, integrated approaches such as late sowing and stale seed beds are difficult to
achieve effectively, often as farmers practically have to take the opportunity to establish crops when
the weather conditions allow. The other factor to consider in this geographical area is that a lot of
growers are reliant on contractors. This drives a preferable need for one pass post emergence, to
include an insecticide for BYDV, and for a treatment with the necessary kickback on the weed
control.
Figure 8 (Met Office 2014)
Figure 7 Wet conditions causing issue
during autumn herbicide application.
12/12/14

15. Methodology
In order to effectively assess the ability to control AMG within winter barley cropping two trials were
carried out:
Northallerton Trial Site
The AMG trial site in Northallerton was
chosen to allow comparison of different
herbicide controls within a high
pressure field. The trial was sown with
Winter Wheat on the 1st
of October
2014. The centre of the field was then
split into plot’s sized 2 x 9.3 m2
. Plots
were then applied with 11 different
treatments with 1 untreated plot,
treatments were split between pre
emergence and post emergence. Both
pre and post emergences were
replicated 3 times.
The crop was winter wheat, but only
chemical herbicides with winter barley approval on the label for pre and/or post emergence
applications were used for this study.
On the 05/01/15 plant counts were undertaken, this was made up of 7 different treatments. A 0.25m2
quadrant was used to gather results, 1 count was taken per plot, this provided 3 counts to be collected
per different treatment. AMG was the only weed counted within the trial, a note was made of any
other present weeds to allow potential for further studies to be identified.
The date of 05/01/15 was chosen to undertake plant counts to allow controlled AMG’s to disappear,
leaving plants which had survived.
Figure 9 AMG Trial site 10/11/14

16. Field’s Assessments in SW Scotland
Fields of Winter Barley were accessed during visits to farms, this allowed real time control of AMG
to be monitored and understand what external factors influenced field operations. Fields were
accessed using a scale system to judge performance.
AMG Present Score
No AMG found within the field 10
Small amounts of AMG found in field corners
and gate ways only
9
Less than ?AMG found per m2
across the field 8
Between 1 – 5 plants m2
7
Between 6 – 10 plants m2
6
Between 11 – 15 plants m2
5
Between 16 – 20 plants m2
4
Between 21 – 25 plants m2
3
Between 26 – 30 plants m2
2
More than 30 AMG plants found m2
1
Figure 10 Field scoring scale used
As well as field scoring each field, notes were taken on previous crop, date of establishment, quality
of seed bed, variety, AMG pressure, the chemical treatment used, any adjuvant use and weather
following application. This information was essential to build up an understanding of what potential
factors led to the field score given to the field and the potential of AMG being a problem within
individual fields.
This allowed a number of different farming systems, different agronomy styles and chemical uses to
be visited building up a picture of how the crop production of winter barley varies across the SW of
Scotland.
Limiting Factors
The study would benefit from undertaking the experiment over a number of years to build up data
upon how variable weather conditions would affect control of AMG. This would improve reliability
of results.
A quadrant was not always available to undertake AMG counts within the field assessment, plants
were counted using a ruler, accuracy would be improved by using the same piece of equipment for
every count.
A trial site within the SW region of Scotland would allow a measurement of how the differing
chemical controls would perform within a different climate.
As these 2 experiments were relatively simple and have not been replicated over differing regions of
the UK, any conclusion drawn will give any reader a general idea of the UK’s current ability to
control AMG however does not guarantee its effectiveness/ineffectiveness.

17. Results and Discussion
Northallerton AMG Trial Site
The graph below shows the control of AMG within the trial plots at Northallerton. The results of pre
emergence and post emergence applications are shown. Treatments have been presented underneath
the graph within a table to ensure ease of reading. Counts were taken on the 5th
of January 2015.
Figure 11
Treatment Letter
Diflufenican + Flupysulfuron-methyl (0.12 kg/ha) A
Diflufenican + Flupysulfuron-methyl (0.06 kg/ha B
Diflufenican + Flupysulfuron-methyl (0.06 kg/ha) +
Pendimethalin (2.5 l/ha)
C
Diflufenican + Flupysulfuron-methyl (0.6 kg/ha) + Flufenacet
(0.25 l/ha)
D
Pendimethalin (2.5 l/ha) + Flufenacet + Diflufenican (0.3 l/ha) E
Diflufenican + Flufenacet (0.3 l/ha) F
From the graph above (Figure 11) it is immediately clear that pre emergence applications preformed
far better to post emergence herbicides, no matter which chemical application was used. This
reinforces that correct timing of herbicide application is essential to ensure optimum control. All
treatments provided 80% + control compared to the untreated plot, which provided a AMG count of
500+ plants. This is even despite treatments going on to pretty dry seedbeds this season.
It must be made clear that Flupysulfuron-methyl does not have on-label approval for use on Winter
Barley post emergence, this is most likely due to there being potential for high levels of crop damage.
However within the AMG trial plots, the crop was Winter Wheat and thus does have an on label
approval for use on WW up until GS33. The reason the results were included within this winter barley
report were to provide evidence that a pre emergence application was still superior over a post
80
82
84
86
88
90
92
94
96
98
100
A B C D E F
%Controlled
Pre versus Post percent controlled
Pre Average
Post Average

18. emergence. Flupysulfuron-methyl does however have an on label approval for pre-emergence
application on WB.
From these results the pre emergence application of flupysulfuron-methyl + diflufenican at 0.06 kg/ha
(B) provided best results producing control of 99.3% throughout the 3 trial plots assessed ed. This was
not expected as the higher application of flupysulfuron-methyl + diflufenican at 0.12 kg/ha (A) would
naturally be expected to provide further improved control however only achieved 94.7%. There were
no visible reasons for why this was not the case on the day of the plant counts, to further understand
this, further counts should be undertaken upon the site and potentially further separate trials
undertaken.
Flupysulfuron-methyl + diflufenican at 0.06 kg/ha with flufenacet 0.25 l/ha (D) also under preformed
compared to “B” treatment providing control of 99%. Treatment “D” had flufenacet added on top of
the same chemistry used in treatment “B”, with an extra mode of action used within the formulation, it
was expected to be the top performer before the data was collected. This also warrants further study
into the effectiveness of adding flufenacet into the treatment, the control on AMG was however the
2nd
best result.
Directly comparing pre and post emergence treatments however, treatments “E” and “F”, provided
similar results at pre emergence, with the inclusion of Pendimethalin on top of Flufenacet and
Diflufenican (E) providing 97.6% control compared to “F”s 97.5%. However, with post emergence
treatments “E” produced control of 89.2% significantly out performing “F” which provided 83.3%
control. These 2 treatments, while not performing as well as the other treatments at pre emergence, do
provide flexibility, with their ability to provide reasonable control upon AMG control up until GS23.
This may be essential within the SW of Scotland where weather conditions can directly affect when
applications can be made to a crop, unlike the other treatments containing Flupysulfuron-methyl
which are limited to pre emergence only in WB.

19. South West of Scotland Field Assessment’s
The graph below (figure 12) shows field scores from visiting fields across the South West of Scotland,
the data has been split up between pre and post emergence and what products were used. The actives
present within each product are listed within the appendix.
Figure 12 Treatment control of AMG in SW Scotland
The graph above mirrors the previous results from the trial site, showing that on all accounts pre
emergence applications were far superior to the later post emergence applications, this was seen no
matter what chemistry was used.
Results from the chemical trials have reduced reliability as some chemical treatments had limited use
within fields in trial area, the herold + picomax and herold + anthem were the most common
treatments used absolute + pendimethalin, herold + klaxon and tower were the least common used.
Absolute + pendimethalin can only be used pre emergence upon WB.
As noted above, the herold + klaxon mix provided optimum control across both pre and post
emergence treatments. However as previously mentioned, this treatment was only used in 6 fields, 4
at post emergence and 2 at pre emergence. Due to this reliability of results is questionable and would
require further investigation. Klaxon (Iodosulfuron-methyl-sodium).
Straight herold was the lowest performer, especially at post emergence applications gaining a 6.22
average field score, the inclusion of pendimethalin improved results, especially at post emergence, the
use of herold and anthem was by far the most popular treatment at both treatment timings.
The inclusion of Herold + Picomax within the mix provided improved control over the herold +
anthem, picomax provided both pendimethalin and picolinafen which provided further control on
AMG and performed well on other weeds, such as fumitory. All though this mix had 4 separate AIs
only had 2 separate modes of action. This provides better defence against resistance than using one
mode of action, and BASIS advisers should bare this in mind as a potential problem.
6
6.5
7
7.5
8
8.5
9
9.5
10
F
i
e
l
d
S
c
o
r
e
Products used
Pre Em
Post Em

20. Seed bed Quality effect on AMG
10 fields were selected upon 2 different farms within a 10 mile radius, they were had all been sown
with the same variety of WB and received the same treatment of flufenacet, DFF and pendimethalin at
pre emergence, all fields received rain within 10 days of chemical treatment being applied. These
fields were selected to reduce the effect on AMG control.
Figure 13 AMG control within different seedbed’s.
Half the fields had a poor seed bed, including large clods and poor consolidation, the remaining 5
fields had firm, fine seed beds and had been Cambridge rolled immediately after sowing, this
provided an optimum seed bed.
From the field scores collected there is a definite correlation between good controls of AMG within
good quality seed beds and poorer control within a poor quality seed bed. The result shows a 1.2
difference between the average field scores.
Choice of establishment method should be tailored to soil type and farming system ensuring crops are
sown within available weather windows when soils allow a fine firm seed bed to be achieved. Use of
Cambridge rollers should be used were seed beds are left with clods post sowing, timing of
Cambridge rollers should be within 48 hours of seed being sown to moister or post GS 13 to avoid
damage to venerable germinating crop.
6.8
7
7.2
7.4
7.6
7.8
8
8.2
8.4
8.6
8.8
Poor Quality Good Quality
Averagefieldscore
Seed bed Quality

21. Non-Selective Herbicide Application Pre Establishment
16 fields which were not ploughed were used within this trial to establish if there was a correlation
between use of a pre establishment herbicide and an improvement with field scores. 8 fields had
received a pre establishment herbicide and 8 fields had not received an application since harvest, these
fields were then field scored, looking at AMG that had been transplanted opposed to establishing from
seed since the crop had been established. An average field score was then found from the 2 groups of
application/non-application and presented within the graph below.
Figure 14
As can be observed from figure 14 the fields with pre establishment applications of a non-selective
herbicide application achieves a field score of +0.825 compared to the fields which received no
application of herbicide pre establishment. This shows a direct correlation between use of non-
selective herbicide pre establishment of the crop within a non-inversion system and improved AMG
control.
This theory is further backed up, as when on field visits the AMG observed was at higher GS
compared to seedling germinators, this was due to already established AMG being transplanted during
establishment field operations. It is generally considered since the removal of IPU and CTU that
AMG cannot be controlled post GS12, due to this the chemistry available within WB herbicides
would be unable to control any transplanted AMG above GS12.
A non-selective herbicide such as Glyphosate offers optimum control of all major weeds within field
production with no known resistance within the UK, this provides 100% of all present weeds at time
of application which in this case is prior to crop establishment. This application is relatively cheap to
undertake as Glyphosate is a commodity product so should be considered where any established
weeds are present.
7
7.2
7.4
7.6
7.8
8
8.2
8.4
8.6
Non-Selective Herbicide Application No Application
AverageFieldScore
Non-Selective Herbicide Application Pre Establishment

22. Further Studies
Reliability of data could be improved with a WB trials site being set up within the SW of Scotland,
this would allow improved understanding of a slightly different climate and rotation would affect
chemical controls. Applications methods could also be assessed achieve optimum performance from
the same chemistry by changing application methods including nozzles, speed of application, water
volume and adjuvant use. Adjuvant use within a high rainfall area would be of great interest,
especially in relation to the DWD.
A study into potential resistance of AMG to AIs would provide an understanding of potential reduced
control.
Further field scale analysis comparing differing treatments, with a larger data pool would provide
improved reliability at farm level. These results are difficult to compare as there are a large number of
external variables make it difficult to draw results from exact reasoning for results.
Further study into loss of yield from AMG would allow the weed to have a cost per Ha to be
understood to land managers.
This could be further analysed to understand loss of performance by harvesting equipment from AMG
being present. This includes reduced harvesting window due to slower drying of crop and straw.

23. Conclusion
From the studies undertaken within this report it has been found that AMG can still be controlled,
however the approach must be a fully integrated approach utilising cultural controls to allow
chemistry available to maintain sustainable control.
Complete agronomy for any crop is essential to prevent weeds, disease or pests having negative
effects upon the crop. The 5 key factors which must be right before a crop should even be considered
to be grown in any field, these are soil structure, which is also directly related to organic matter, soil
pH, P and K levels within the soil. With a lack of any one of these factors crop failures are a high
possibility, a crop with optimum core elements present will be far more competitive versus AMG
reducing any effects.
At application of AIs any potential aids to improve efficacy upon target should be used, this includes
use of adjuvant suited to operation being carried out. I would suggest a paraffin oil type adjuvant such
as Remix, for a residual herbicide, this would reduce drift, improve longevity of AIs within the top of
the soil, reduce risk of AIs being washed down to crop rooting zones which could potentially have
hazardous effects and improve cover to the ground.
Application of residual herbicides using VP80 flat fan nozzles within a twin line system at 300 litres
of water would provide most effective application method.
It is suggested that post emergence chemical applications have been significantly reduced with the
loss of AIs such as CTU and IPU which were residual herbicides with contact action within WB
cropping, this correlates with results showing that pre emergence treatment timings are by far superior
to post emergence for the control of AMG.
My recommendation for a land manager within the SW of Scotland would be to use a non-selective
herbicide pre cultivation to remove any germinated AMG which would not be controlled post
establishment of the crop. A plough based system would also bury any newly germinated AMG or
any seeds left from previous cropping. Establishing the crop at an optimum timing to ensure best seed
bed ensuring a fine firm seed bed with optimum seed to soil contact for the crop. Seed used should be
dressed with Deter seed dressing, this will reduce risk of BYDV being vectored onto the crop for up
to 6 weeks. A pre emergence herbicide treatment of Flupysulfuron – methyl, flufenacet, diflufenican
and pendimethalin plus Remix adjuvant would provide an optimum control upon AMG. This mix
would also provide good resistance management with 3 separate modes of action. This treatment must
be made pre emergence, preferable within 36 hours of sowing with some precipitation following the
application to improve efficiency.
A slightly more flexible application of flufenacet, diflufenican, pendimethalin and picolinafen would
allow applications to be made at post emergence up until GS23 of the WB crop. This would work well
at pre emergence, however control would be reduced the longer the seed bed was not applied with
herbicide after sowing as AMG would being to establish.
Due to the results I have accepted my null-hypothesis meaning that AMG can still be controlled
effectively within winter barley cropping in the SW of Scotland.

24. Appendix

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