Phenoxy Reference Guide www.nufarm.com.au 3

Contents

Introduction 4

Mode of Action 4

Cereal Crop Growth Stages (including Zadok’s guide) 5

A Numerical Cereal Growth Scale – Zadok’s 6

What Phenoxy Where? 6

Common Weeds Controlled 7

Using the Growth Stage of Cereal Crops to Time Applications 8

Damage to Cereal Crops from Incorrect Applications 9

Salvage Spraying of Winter Crops 10

Cereal Tolerance Guide 11-13

Plant Back Periods for Fallow Seed Bed Preparation 14-15

Spray Grazing 16

Withholding Periods 16

Reducing Off-Target Herbicide Drift 16-19

Herbicide Resistance Management 20 4

Introduction At Nufarm, we are committed to supporting Australian growers Phenoxys were first developed in the USA in the early 1940’s with the highest quality crop protection and weed control and used commercially in 1946. Today they remain amongst products so maximum outputs can be achieved. the world’s most widely used , providing farmers and other users with broadleaf weed control in a multitude of Our commitment starts with the utilisation of world-leading agricultural and non-agricultural uses. Phenoxys work by manufacturing and environmental control technology. This is disrupting plant cell growth and form a part of the Group I reflected in research and development, container management, herbicides. and the establishment of regional service centres across Australia. Nufarm guarantees its Phenoxy products, which include Nufarm Amicide® 625, Nufarm Estercide® 800, Nufarm LV Nufarm, an Australian company, is a global leader in the Estercide® 600, Nufarm Surpass® 300, Nufarm Buttress®, manufacture, supply and marketing of 'phenoxys', with Baton®, Nufarm LVE MCPA and Nufarm MCPA 500. manufacturing plants in Australia (Melbourne), England (Belvedere), Austria (Linz) and the Netherlands (Botlek).

Mode of Action Phenoxy herbicides mimic the plant growth regulator indol-3- concentrations are highly regulated in plants by synthesis, acetic acid (IAA), or in plants, thus it is necessary to degradation and both reversible and non-reversible review the function of auxin in plants to properly understand conjugation. Synthesis increases the IAA content, while their mechanism of action. degradation decreases it. Conjugation, which is the linking of IAA to another molecule, frequently an amino acid, inactivates Role of in Plants – Auxin is a plant growth IAA. However, if conjugation is reversible, it may act as a slow regulator that controls cell enlargement, division and plant release mechanism for maintaining relatively constant IAA development through the plant life cycle. levels.

While much remains to be unravelled about the workings of Auxin Herbicide Mode of Action – Auxinic IAA, it is known that IAA binds to auxin binding proteins (ABPs) herbicides (‘phenoxys’) presumably bind to some or all of the located in the following: same sites as naturally occurring IAA and cause similar effects. • The cell membrane However, the amount of auxinic herbicides available to the • The endoplasmic reticulum (an internal cellular membrane plant is uncontrolled and, thus, auxin-like activity is unchecked. system) Plant growth becomes deregulated.

• The cell nucleus Metabolic reserves are mobilized and transported to the site of • The cytoplasm growth, usually meristematic regions. Unregulated growth leads to twisting, thickening and elongation of leaves and The control of growth that IAA exerts is multifunctional. stems. Auxinic herbicides are active primarily in growing Changes induced by IAA cause rapid changes in cell plants. Plant death is gradual, due to the unconstrained elongation and both rapid and slow changes in gene mobilisation of reserves, the breakdown of repair mechanisms expression. Auxins influence other growth regulators including and, finally, the loss of function. cytokinins, abscisic acid and ethylene (a gas that functions as a plant growth regulator). Source: "How Herbicides Work: Biology to Application", Alberta , Food and Rural Development. The concentration of IAA in plant cells regulates cell growth. However, plant tissues differ in their sensitivity. Depending on tissue type and IAA concentration, IAA may either inhibit or stimulate a response.

IAA is a component of a carefully balanced system. IAA

Nufarm Phenoxy Reference Guide www.nufarm.com.au 5

Cereal Crop Growth Stages (including Zadok’s guide)

Crop 2-leaf stage Start of tillering Tillering stage Fully tillered stage Start of jointing Early boot stage growth Two leaves (L) First tiller (T1) Tillers come from Usually no more tillers Jointing or node The last leaf to form – the stage have unfolded; appears from the base where form after the very formation starts at the flag leaf – appears on top third leaf present, between a lower leaves join the young head starts end of tillering. Small of the extended stem. The yet to fully leaf and the main stem and continue forming in the main tiller. swellings – joints – form developing head can be felt expand shoot. Usually 3 or forming, usually Tillering completed at the bottom of the as a swelling in the stem. 4 leaves are on the until there are 5 when first node detected main tiller. Heads main tiller. leaves on the main at base of main stem. continue developing shoot. Secondary and can be seen by roots developing. dissecting a stem. Zadok’s 2 leaves unfolded 4 leaves unfolded 5 leaves on main 6 leaves on the main Z35-Z45. decimal (Z12) (Z14). shoot or stem shoot or stem (Z16). First node formed at code Main shoot and 1 (Z15). Main shoot Main shoot and three base of main tiller (Z31). tiller (Z21). and 1 tiller (Z21). tillers (Z23). Herbicide Suitable stage for Suitable stage for Suitable for Many herbicides can Suitable for 2,4-D No herbicide should be spraying spraying many spraying at the 3-4 spraying many be sprayed up to the spraying. applied at this stage. Too stage herbicides, but too leaf stage. Too early herbicides at the end of tillering. Suitable late for 2,4-D application early for 3 leaf for the 5 leaf stage 5 leaf tillering for 2,4-D spraying. except harvest aid stage of application. of application. stage. applications.

• There is no difference between spring varieties sown on the same day in the rate of appearance of new leaves. • At the early boot stage, the last flowering part - the pollen - is being formed. This occurs earlier in barley than in wheat or triticale.

Source: ‘Weed Control in Winter Crops 2004’, NSW Agriculture. 6

A Numerical Cereal Growth Scale – Zadok’s A decimal scale describing cereal crop growth stages is now The main stages of interest to cereal producers applying widely used. This scale, called Zadok’s decimal code, herbicides are: describes the principal growth stages: 1 Seedling Growth 2 Tillering 3 Stem Elongation 4 Booting 0 Germination 4 Booting 7 Milk Development Zadok’s scale is based on the individual plant, not the general 1 Seedling Growth 5 Ear Emergence 8 Dough Development appearance of the crop. Therefore, to use the scale, a 2 Tillering 6 Flowering 9 Ripening representative selection of plants should be examined from a 3 Stem Elongation paddock.

Each primary growth stage is further subdivided into secondary Other commonly referred to growth stages: stages extending the scale from 00 to 99. 3 leaf: 3 fully unfolded leaves on the main shoot only. Zadok 13. The first number represents the growth stage and the following number indicates the number of plant parts, e.g. Z12 indicates Double ridge – when the cereal plant changes from leaf production to ear initiation, normally around 4-6 leaves on the a young plant with only two leaves fully unfolded, commonly main stem. Zadok 14-16. referred to as 2 leaf stage. See the first diagram in Cereal Crop Growth Stages (p5). 5 leaf: 5 fully unfolded leaves on the main shoot only. Zadok 15.

A series of pairs of numbers can be used to further describe the Tillering: Tiller formation period. Plants past seedling stage and growth stage. For example 14/21 indicates the main tiller with before stem elongation. Zadok 21 to 29. See the diagrams in 4 fully unfolded leaves, commonly referred to as the 4 leaf Cereal Crop Growth Stages. stage, but this plant has the main stem and one more tiller. Note that additional tillers are counted separately to the main tiller. Jointing: Crop becoming erect or booting up to the stage when See the second diagram in Cereal Crop Growth Stages. the flag leaf is just visible. Zadok 31 to 39. See the fifth diagram in Cereal Crop Growth Stages.

Boot: Head plainly felt in the stem before head emergence. Zadok 35 to 45. See the sixth diagram in Cereal Crop Growth Stages.

What Phenoxy Where?

Product Summer Tank mix Tankmix Tankmix Tankmix Post-em tank Tankmix most Spray/Graze in Early post-em Late post-em Weeds / SpraySeed®2 Roundup® diuron grass mix with SU trace pasture in cereals in cereals melons herbicides herbicides elements

MCPA 500 0 0 X ✔ X ✔ X ✔ ✔ 0

LVE MCPA 0 ✔ ✔ ✔ ✔ ✔ ✔ 0 ✔ 0

Amicide® 625 ✔ ✔ X ✔ X ✔ X ✔ X ✔

LV Estercide® ✔ ✔ ✔ 0 X ✔ ✔ X X ✔ 600

Estercide® 800 ✔ ✔ ✔ 0 X 0 ✔ X X 0

Buttress® 0 0 X ✔ X 0 X ✔ X X

Surpass® 300 0 0 ✔ 0 X 0 X 0 X 0

✔ Recommended 0 Not preferred X Not recommended option

Nufarm Phenoxy Reference Guide www.nufarm.com.au 7

Common Weeds Controlled

Amicide® 625 Buttress® Estercide® 800 LV Estercide® 600 LVE MCPA MCPA 500 Surpass® 300 Bathurst Burr 800ml-2.2L 1.0-3.2L 700ml-2.8L 900ml-3.7L 1.6L 1.0-2.0L 1.6-2.3L Bladder Ketmia Capeweed 1.1-2.8L 2.1-3.2L 450ml-1.4L 600ml-3.7L 1.7L 2.1L 2.9-5.8L Erodium 1.4-3.2L 700ml 900ml 400-500ml (in mix) 2.9-6.6L Fat Hen 560ml-1.7L 1-3.2L 350ml-700ml 460ml-900ml 1-1.6L 1.0-2.0L 1.2-3.5L Flatweed / Dandelion 1.1L 1.6L 1.4-2.2L Fleabane 1.8-3.5L 3.6-7.3L Fumitory 560ml-1.7L 2.1-3.2L 350ml-2.8L 460ml-3.7L 1.1L 1.4L 1.1-3.5L Heliotrope 1.1L Hexham Scent 1.1-1.7L 1.2-1.5L 2.3-3.4L Hoary Cress 900ml-1.7L 700ml-2.8L 900ml-3.7L 2.1-4.5L 1.8-3.4L Hogweed 1.4L 2.1-3.2L 700ml-1.4L 900ml-1.9L 2.9L Horehound 1.4-3.2L 700ml-2.8L 900ml-3.7L 2.1-3.0L 2.9-6.6L Indian Hedge Mustard 1.1-1.4L 1.0-3.2L 465ml-2.9L Noogoora Burr 800ml-1.1L 1.0-3.2L 700ml-2.8L 900ml-3.7L 1.6L 1.0-2.0L 1.6-2.3L Saffron Thistle 560ml-1.7L 2.1-3.2L 1.1-1.9L Salvation Jane 1.1-2.2L 2.1-3.2L 1-4L Skeleton Weed 1.4-1.7L 700ml-2.8L 900ml-3.7L 1.1-1.6L 1.5-2.0L 2.3-4.6L Spiny Emex 1.4L 400-500ml (in mix) 2.9L St Barnaby's Thistle 1.0-1.4L 1.3-1.9L Turnip Weed 560ml-1.1L 1.0-3.2L 350-700ml 460-900ml 700ml-1.1L 1.0-1.1L 1.1-2.3L Variegated Thistle 560ml-1.7L 1.0-3.2L 350ml-2.1L 460ml-3.7L 840ml-1.1L 700ml-1.5L 1.1-3.5L Vetch 1.1-1.4L 550-700ml 700-900ml 2.3-2.9L Tares 1.1-1.4L 550-700ml 700-900ml 2.3-2.9L Wild Mustard 650ml-2.8L Wild Radish 800ml-1.7L 350-700ml 460-950ml 1.1-1.6L 700ml-2.0L 1.6-3.5L Wild Turnip 225ml-1.4L 180-700ml 240-950ml 500ml-1.5L 700ml-2.0L 465ml-2.9L Wireweed 1.4L 2.1-3.2L 700ml-1.4L 900ml-1.9L 2.9L

Note: These rates are a guide only and further information should be sought from the label for weed size, tankmix recommendations and state registrations. Further weed species and rates are included in the product label - for further advice or instructions refer to the product label. Photographs courtesy of Department of Primary Industries, Queensland.

Variegated Thistle (Silybum marianum) 8

Using the Growth Stage of Cereal Crops to Time Herbicide Applications

It is important to consider the crop growth stage when timing In many cereal crops: herbicide applications. • 3 leaf (on main stem) stage is before tillering.

Barley, oats and winter sown in early autumn for • 5 leaf (on main stem) stage coincides with early tillering. grazing develop much more quickly to the tillering stage than • 6-7 leaf (on main stem) stage coincides with mid to fully cereals sown in May-June. Given adequate moisture and warm tillered stage. weather, early development can be relatively quick. • Jointing or node formation indicates the start of the reproductive phase in the crop, and tillering can be said to The terms ‘early tillering’ and ‘late or fully tillered’ are not be complete. definitive and are commonly used in a very general sense. The number of fully emerged main shoot or stem leaves, together The table below provides an indication of recommended with the number of tillers when there is more than one, is the timings for different phenoxy products. only accurate, definitive description of the growth stage of a cereal plant. See the diagrams in ‘Cereal Crop Growth Stages’, and ‘A Numerical Cereal Growth Scale – Zadok’s’.

Cereal growth stage Product Chemical 2 leaf 3 leaf 4 leaf 5 leaf – Mid till Late till Full till-Jointing Booting early till

Zadok 12 13 14 15-21 25 29 30 40 Cereal Code

MCPA 500 MCPA 0.7L

MCPA 0.7 – 2.1L

LVE MCPA MCPA 0.5L

MCPA 0.5 – 2.1L

Amicide® 625 2,4-D amine

Estercide® 800 2,4-D ester

LV Estercide® 600 2,4-D ester

Buttress® 2,4-DB

Recommended and preferred timing Less preferred timing

The recommended timing of application has been determined after significant research, with the aim of minimising crop damage and maximising yield. Particular attention should be given to two vital stages of crop development - 3 to 5 leaf stage or commencement of tillering and at the start of jointing.

Nufarm Phenoxy Reference Guide www.nufarm.com.au 9

Damage to Cereal Crops from Incorrect Phenoxy Herbicide Application

Cereal crops are sensitive to phenoxy herbicide application at several growth stages throughout the season. The sensitive timings usually coincide with periods of high growth or reproductive activity. Research has shown that applying phenoxys in the incorrect application window or at an incorrect rate can result in yield losses of up to 30%.

The level of damage from incorrect application depends on several of the following factors: Crop Variety There are variations amongst cereals with oats often displaying the greatest sensitivity to many phenoxy herbicides.

Different varieties demonstrate different sensitivities – and often double ridge at different timings.

Herbicide Type and Formulation Untreated Carnamah head 2,4-D Ester 0.75L/ha at Z14 • 2,4-D is often more damaging than MCPA Carnamah • Ester formulations are often more damaging than amine formulations Visual effects from each of these application timings can vary • Higher rates usually result in more damage than lower rates with the double ridge timing often appearing as distorted or • The addition of oils and wetting agents can aggravate the twisted heads later in the season when the grain heads emerge. effect of the herbicide This is normally accompanied by some missing grains in the head. Early boot and flowering applications usually express symptoms as empty heads and missing grains with distortion Variations in Crop Development being uncommon. Crops that experience uneven emergence or establishment often have variations in crop development at the time of spraying. Crop Development Stage It is critical to correctly identify stages of crop development to avoid damaging the crop with phenoxy herbicides.

Research has demonstrated that cereals are most sensitive at the following growth stages:

a) The double ridge stage, which usually occurs between 4 and 5 leaf on the main stem in cereals (Z14-15). This is when the cereal plant changes from leaf production to ear initiation. Damage at this growth stage is affected by application rate and varietal characteristics.

b) Early boot (Z41-43) when the flag leaf sheaf is extending and swelling of the grain head can be seen in the stem.

c) Flowering / Anthesis (Z61-69)

The time taken for a crop to change from being safe to apply herbicides to being unsafe can be as little as 6 days. 10

Salvage Spraying of Winter Crops Situations may arise, due to late establishing weeds combined poppy, wild radish and black bindweed can contaminate with wet and prolonged spring or harvest periods, where grain. salvage spraying or pre-harvest desiccation may be necessary ® TM1 to assist timely harvesting of winter crops. Amicide 625 and Roundup PowerMAX have a role in salvage spraying and pre-harvest desiccation of winter crops. Weeds such as skeleton weed, sowthistle, prickly lettuce, fat The following table summarises the use patterns for Amicide® hen and New Zealand spinach can interfere with harvesting. 625 and Roundup PowerMAXTM1. Weed seeds such as saffron thistle, rough poppy, Mexican

Herbicide Product Amicide® 625 Estercide® 800 Roundup PowerMAXTM1

Chemical 2,4-D Amine 625g/L 800g/L 540g/L

Registered Registered (All states) All states except Registered (All states) Tasmania

Crop Winter Cereals Winter Cereals Wheat

Rate 1.2 – 1.7L/ha 1.4L/ha 0.905 – 1.8L/ha

Crop safety Apply after late dough stage in wheat Apply after dough Apply after late dough stage in wheat stage of crop

Harvest Withholding period Nil when used as directed 7 days 7 days

Application Ground / Aerial Ground / Aerial Ground / Aerial

* For crops other than wheat refer to the product labels.

Wild Radish (Raphanus raphanistrum) Photographs courtesy of Department of Primary Industries, Queensland.

Nufarm Phenoxy Reference Guide www.nufarm.com.au 11

Cereal Tolerance Guide Tolerance of Barley Varieties to Post-Emergent Herbicides Variety Bromoxynil Bromoxynil MCPA + MCPA MCPA MCPA + 2,4-D + MCPA + MCPA + LVE Diflufenican amine dicamba Bromicide® Bromicide® MA BroadsideTM Kamba® M MCPA 500 LVE MCPA Nugrex Amicide® 625 200 (b) (b)

Product/ha 2.1L 2.1L 1.4L 1.4–1.7L 0.7L 1.2L 0.5L 1.0L 0.75L 1L 1.7L

Arapiles – – – – – – – – –

Barque S – – W S – – – – – S

Binalong W – – w – S – N W – S

Franklin S N – S S W S – – W S

Gairdiner W – – S S* N – S W – W

Grimmett N W W 0–15 N N N W – S –

Lindwall S – – – S S Q S – – S S

Mackay Q S – – S* S* W – – S* – W

Namoi – – – S – S – – – – S

Schooner W 0–15 N 0–15 S S W N S S W

Skiff S S – N N S N W – W S

Sloop W – – W S W S N W S W

Tantangara N – S N* S* W – – N S W

Tilga – – – – S S S S – S S

Yambla S – – S – – N S – – –

Wyalong N – – S S N – S – – S

Growth stage 3–4 leaf 5 leaf 3 leaf 5 leaf 5 leaf 5 leaf 3 leaf 5 leaf 5 leaf 3-4 leaf 5 leaf

Note: 1. Figures are the range of percentage yield reductions measured. 2. The occurrence of cold, wet seasonal conditions at or just after spraying a herbicide can result in significant yield loss in sensitive varieties. b = Not recommended, crop stage too early. – = Not tested. * = Tested one year only. W = Warning, damage possible – damage recorded only once at the recommended rate. Q = QDPI Data. N = Narrow safety margin – damage recorded at twice the recommended rate. S = Safe.

Source: ‘Weed Control in Winter Crops 2004’, NSW Agriculture. 12

Tolerance of Wheat Varieties to Post-Emergent Herbicides Variety Bromoxynil MCPA MCPA + LVE MCPA Bromoxynil 2,4-D + MCPA + Dicamba Diflufenican + MCPA amine Bromicide® MA Kamba® M Nugrex LVE MCPA Bromicide® Trooper® Amicide® 625 (a) 200 Product/ha 2.1L 1.7L 1.7L 0.5L 1.0L 1.2L 2.1L 1.0L 1.0L 0.2L 2.1L Annuello* – – S – S – S–––S Babbler – – N – – – W – S* – W* Bowerbird – – N – S – –– –– – Bowie – – S – N – S– S– W Braewood – – W – S – S– S– S Chara – – S – S – S* – W* – S* Cunningham – – – S – W SS –N N Currawong S* – S* S S S S– –S S Diamondbird – S N – S – S – W* – W* Drysdale – S – – S* – S– S– W EGA Bellaroi Q* – – – – – S –S –S S EGA Hume Q* S – – – – S S– S– – EGA Wedgetail – N – – – – S– S– W Giles – – N – S – 0–10 – W* – W* Goldmark – N N S S – S– –– S H45 – – W – S – SN –– – H Apollo S – S S S – SN –S – H Mercury – – N S N – S– –S – Janz S – S* N N N N– S*N N Kamilaroi N S N – S – –N NS – Kennedy Q* – – – – – S S– S– S Lang Q* – – – – – S S– S– S Lorikeet – – W – S – S– –– S Pardalote – – S – S – S– –– S Petrel – – S – S – S– –– – Petrie Q – – – – – – SS –– S QALBis Q* – – – – – S –– S– – Rosella S W S S N S SN NN N Snipe – – N – – – –– –– – Strzelecki Q S* – – – – N S– S– S Sunbri – – – N – N S– –N N Sunbrook – – S S S – –– –– – Sunco N – W S N N –– N– – Sunsoft 98 – – 0–15 – S – S– –– W Sunstate S – – – – S W– –S N Sunvale – – S S – – S– –– – Thornbill – – S – W – S– –– S Whistler – – S – S – –– –– – Wollaroi S – S S S S S– –N S Wylah – – W – S* – S– –– S Yallaroi N – N S N S S – N 0–10 N Crop stage at 5 leaf 3–4 leaf 5 leaf 3 leaf 5 leaf 5 leaf 3 leaf 3 leaf 5 leaf 3 leaf 5 leaf application

Note: 1. Figures are the range of percentage yield reductions measured. 2. The occurrence of cold, wet seasonal conditions at or just after spraying a herbicide can result in significant yield reduction in sensitive varieties. a = Not recommended: crop stage too early. S = Safe. – = Not tested. Q = QDPI Data. W = Warning, damage possible – damage recorded only once at recommended rate. * = Tested one year only. N = Narrow safety margin – damage recorded at twice recommended rate. ** = +0.5% Uptake oil.

Source: ‘Weed Control in Winter Crops 2004’, NSW Agriculture. Nufarm Phenoxy Reference Guide www.nufarm.com.au 13

Tolerance of Oat Varieties to Post-Emergent Herbicides Variety MCPA + Bromoxynil MCPA + 2,4-D Bromoxynil MCPA Metosulam + Dicamba Diflufenican amine MCPA LVE MCPA LVE Kamba® Bromicide® Nugrex Amicide® 625 Bromicide® LVE Eclipse®4 M 200 MA MCPA MCPA LVE Product/ha 1.7L 2.0L 1.0L 1.0L 2.0L 1.6L 5g + 0.5L Barcoo – S – 0–40 – – – Bimbil N W S – – – – Carrolup N 0–10 0–10 – – – – Cooba N W N – – – – Coolabah S W N – – – – Echidna 0–50 W W W W S S Eurabbie W S S 0–55 S S S Euro N W N – – – – Gwydir S* N 0–20 0–20 – – – Mortlock N 0–10 N – – – – Possum* W W S S – – – Quall W* S N W – – – Taipan S W W W – – – Warrego* S S S W – – – Yarran 0–25 W W W W S S Yiddah* N W S N – – – Crop stage at 5 leaf 3 leaf 3 leaf fully tillered 5 leaf 5 leaf 3-4 leaf application N = Narrow safety margin – damage recorded at twice recommended rate. – = Not tested. S = Safe. * = Tested in 1 year only. W = Warning, damage possible – damage recorded only once at recommended rate. Figures are the range of percentage yield reduction measured.

Tolerance of Triticale and Ceral Rye Varieties to Post-Emergent Herbicides Tolerance of Field Pea Varieties to Herbicides Variety MCPA + MCPA + 2,4-D In addition to the herbicides in the table below, most field pea varieties Dicamba Diflufenican amine have been tested for tolerance to the post-emergent grass herbicides indicating that Aramo®1, Correct®3, Fusilade®2, Fusion®2, Kamba® Nugrex® Amicide® 625 Targa®5, Select®6, Sertin®3 and Verdict®4 are safe. M Variety MCPA Product/ha 1.7L 3.0L 1.0L MCPA 500 Abacus W 0–15 S Product/ha 0.7L Credit S* 0–10 W Alma N Eleanor 0–9 S S Glenroy – Everest S 0–10 S Dundale N Hillary W S W Excel – Jackie W W W Kaspa – Kosciuszko* S S S Morgan – Maiden S – – Mukta – Muir N S – Parafield – Prime 322 S* S S Snowpeak – Ryesun S N – Tahara S S – S = Safe. Tickit* W W W W = Warning, damage possible – damage recorded only once at recommended rate. Treat* W W W N = Narrow safety margin – damage recorded Crop stage at 5L 3L 5L at twice recommended rate. application – = Not tested. N = Narrow safety margin – damage recorded at twice recommended rate. S = Safe. W = Warning, damage possible – damage recorded only once at recommended rate. – = Not tested. * = Tested in 1 year only. Figures are the range of percentage yield reduction measured. Source: ‘Weed Control in Winter Crops 2004’, NSW Agriculture. 14

Plant Back Periods for Fallow Seed Bed Preparation Plant Back Periods (Days)

Nufarm Amicide® 625 Nufarm Estercide® 800/Nufarm LV Estercide® 600

Estercide® 800 Up to 440mL – 860mL – Crop Rates 440mL/ha 860mL/ha 1.31L/ha

Up to 560mL – 1.1L – Up to 580mL – 1.15L – LV Estercide® 600 560mL/ha 1.1L/ha 1.7L/ha 580mL/ha 1.15L/ha 1.8L/ha

Balansa Clover 7 7 10 Balansa Clover 7 7 10 Barley % 1 1 3 Barley % 1 1 3 Chickpeas # 7 14 21 Chickpeas # 7 14 21 Cotton 10 14 21 Cotton 10 14 21 Faba Beans 7 7 10 Faba Beans 7 7 10 Field Peas 7 14 14 Field Peas 7 14 14 Lentils 7 7 10 Lentils 7 7 10 Linseed 7 7 14 Linseed 7 7 14 Lucerne 7 7 10 Lucerne 7 7 10 Lupins + 7 14 21 Lupins + 7 14 21 Medics 7 7 10 Medics 7 7 10 Narbon Beans 7 7 10 Narbon Beans 7 7 10 Navybean 10 10 14 Navybean 10 10 14 Oats 3 3 7 Oats 3 3 7 Perennial Ryegrass 7 7 10 Perennial Ryegrass 7 7 10 Persian Clover 7 7 10 Persian Clover 7 7 10 Phalaris 7 7 10 Phalaris 7 7 10 Canola / Rapeseed # 14 21 28 Canola / Rapeseed # 14 21 28 Rice 7 7 14 Rice 7 7 14 Safflower # 7 14 21 Safflower # 7 14 21 Sorghum @ 3 7 10 Sorghum @ 3 7 10 14 14 21 Soybean 14 14 21 Sub-Clover 7 7 10 Sub-Clover 7 7 10 Sunflower @ 7 10 14 Sunflower @ 7 10 14 Triticale 1 3 7 Triticale 1 3 7 Vetch 7 7 10 Vetch 7 7 10 Wheat % 1 3 7 Wheat % 1 3 7 White Clover 7 7 10 White Clover 7 7 10

Important: When applied to dry soils at least 15mm (1/2 inch) Important: When applied to dry soils at least 15mm (1/2 inch) of of rain must fall prior to the commencement of the plant back rain must fall prior to the commencement of the plant back period. period. Notes: Notes: % In Queensland, no rainfall is required to fall prior to % In Queensland, no rainfall is required to fall prior to commencement of Plant Back Period for wheat, barley and commencement of Plant Back Period for wheat, barley and triticale. triticale. # In Queensland, planting canola/rapeseed, chickpeas and # In Queensland, planting canola/rapeseed, chickpeas and safflower must be delayed for at least 14 days following safflower must be delayed for at least 14 days following rainfall rainfall of at least 15mm. of at least 15mm. @ In Central Queensland, when using 830mL/ha or less of LV @ In Central Queensland, when using 800mL/ha or less of Estercide® 600, or 625mL/ha or less of Estercide® 800, the Plant Amicide® 625, the Plant Back Period for sorghum and sunflower Back Period for sorghum and sunflower is 1 day irrespective of is 1 day irrespective of rainfall. rainfall. + In WA the Plant Back Period for lupins at all rates is 28 days. + In WA the Plant Back Period for lupins at all rates is 28 days.

Nufarm Phenoxy Reference Guide www.nufarm.com.au 15

Nufarm Surpass® 300

Crop Rates

Up to 1.1L/ha 1.1L – 2.3L/ha 2.3L – 3.4L/ha

Balansa Clover 7 7 10 Barley % 1 1 3 Chickpeas # 7 14 21 Cotton 10 14 21 Faba Beans 7 7 10 Field Peas 7 14 14 Lentils 7 7 10 Linseed 7 7 14 Lucerne 7 7 10 Lupins + 7 14 21 Medics 7 7 10 Narbon Beans 7 7 10 Navybean 10 10 14 Oats 3 3 7 Perennial Ryegrass 7 7 10 Persian Clover 7 7 10 Phalaris 7 7 10 Canola / Rapeseed # 14 21 28 Rice 7 7 14 Safflower # 7 14 21 Sorghum @ 3 7 10 Soybean 14 14 21

Sub-Clover 7 7 10 Photographs courtesy of Department of Primary Industries, Queensland. Sunflower @ 7 10 14 Triticale % 1 3 7 Vetch 7 7 10 Wheat % 1 3 7 White Clover 7 7 10

Important: When applied to dry soils at least 15mm (1/2 inch) of rain must fall prior to the commencement of the plant back period. Notes: % In Queensland, no rainfall is required to fall prior to commencement of Plant Back Period for wheat, barley and triticale. # In Queensland, planting canola/rapeseed, chickpeas and safflower must be delayed for at least 14 days following rainfall of at least 15mm. Above: Wild Turnip (Brassica tournefortii) @ In Central Queensland, when using 1.6L/ha or less of Surpass® 300, the Plant Back Period for sorghum and sunflower is 1 day irrespective of rainfall. + In WA the Plant Back Period for lupins at all rates is 28 days. 16

Spray Grazing The decision to spray graze depends on the composition of the The effect from the herbicide over-stimulates weed growth. As a pasture and the target weeds present. To warrant spray grazing result starch in the weeds rapidly converts to sugar, making the there should be at least 150 legume plants per m2 and greater weeds more palatable to grazing stock. than 30% broadleaf weeds. MCPA 500 is often softer on pasture legume species than The technique involves spraying low rates of Amicide® 625 or Amicide® 625 and clovers are more tolerant than medics to MCPA 500 onto the pasture. This is followed with a program these herbicides. of heavy grazing, at least five times the normal stocking rate. In normal seasons actively growing weeds are sprayed from Nufarm produces a separate pasture tolerance guide publication. about 6 weeks after the autumn break. Withholding Periods Nufarm Amicide® 625 Nufarm LVE MCPA Pasture, Cereal Crops – Do not graze or cut for stock food for Pasture, Cereal Crops – Do not graze or cut for stock food for 7 days after application. 7 days after application. Harvest Withholding Period: Not required when used as Nufarm MCPA 500 directed. Cereals, Pasture - Do not graze or cut for stock food for 7 days In Tasmania, this product may only be used from 15 April to after application. 15 September unless otherwise permitted by the Registrar of Pesticides. Harvest Withholding Period not required when used as directed.

® Nufarm Buttress® Nufarm Surpass 300 Do not graze or cut for stock food for 7 days after application. Pasture, Cereal Crops – Do not graze or cut for stock food for 7 days after application. ® Nufarm Estercide 800 Crop Harvest: Not required when used as directed. ® Nufarm LV Estercide 600 In Tasmania, this product may only be used from 15 April to Pasture, Cereal Crops - Do not graze or cut for stock food for 15 September unless otherwise permitted by the Registrar of 7 days after application. Pesticides. Reducing Off-Target Herbicide Drift

In areas where a range of agricultural enterprises co-exist, How Many Types of Drift are There? conflicts can arise, particularly from the use of pesticides. A Herbicides can drift as droplets (spray), as vapours or as major problem that can occur is damage to susceptible crops particles. Spray drift is the most common form of off-target effect. caused by “off-target” herbicide drift. All herbicides are Vapour and particle drift are different to spray (droplet) drift. capable of drift if applied in the wrong manner or wrong conditions, regardless of the active ingredient or the Spray Drift (Droplet) – is the easiest to control because formulation type. under good spraying conditions, droplets are carried down by air turbulence and gravity, to collect on plant surfaces. Under Herbicide users have a moral and legal responsibility to nil wind conditions and very windy conditions, droplets, prevent herbicides from drifting and contaminating or especially fine droplets, can be carried off-target. This can damaging neighbours’ crops. Sensitive crops may be up to occur regardless of the herbicide used. Spray drift is the major 10,000 times more sensitive than the crop being sprayed. Even offender for off-target effects. small quantities of drifting herbicide can cause severe damage to highly sensitive plants. How to Minimise Spray Drift • Before applying any herbicide, always check for susceptible crops in the area

• Notify neighbours of your spraying intentions

Nufarm Phenoxy Reference Guide www.nufarm.com.au 17

• Always monitor meteorological conditions carefully and is not stable and sways and dips below the optimum height. understand their effect on “drift hazard” 2. Fit nozzles that don’t produce a fine droplet spectrum. • Record weather conditions, wind direction, herbicide and Nozzles that produce larger droplets such as Spraying water rates and operating details for each paddock Systems, TurboTeeJet®8, DriftGuard or Air Induction nozzles (or • Supervise all spraying even when a contractor is employed similar from other manufacturers) are less prone to off-target movement and are still very satisfactory for optimum herbicidal o • Spray when temperatures are less than 28 C performance from the phenoxys.

• Don’t spray if conditions are not suitable (use delta T) o 3. 110 nozzles produce a higher percentage of fine droplets o • Maintain a down-wind buffer than 80 nozzles, however, they allow a lower boom height while maintaining the required double overlap. • Minimise spray release height 4. Operate within the nozzle pressure range recommended by the • Use large droplets, where appropriate, to give adequate nozzle manufacturer. Lower volumes such as 30-40L/ha produce spray coverage a higher percentage of fine droplets than higher spray volumes • If in doubt – then don’t spray applied at the same pressure and from the same nozzle.

Vapor drift – arises directly from the spray or evaporation of 5. While not always the case, aircraft application generally herbicide from sprayed surfaces. Changing to a less volatile or has an inherently greater risk of spray drift than ground rig non-volatile formulation reduces this risk. application. This is due to a number of factors including lower application volume, small droplet sizes, height of application, Particle drift – occurs when water and other herbicide and turning and wing tip vortices. An aircraft should not be carriers evaporate quickly from the droplet leaving tiny used to apply herbicides in areas where highly susceptible particles of concentrated herbicide. This can occur to many crops are growing. types of pesticides. Vapours and minute particles float in the air stream and are poorly collected on catching surfaces. They Use a Low-volatile Formulation may be carried for many kilometres in thermal up-draft before Ester-based formulations are recognised as the most volatile being deposited. phenoxy formulations – changing to a non-volatile amine or salt formulation reduces risk. Even changing from an ethyl-ester to What Factors Affect the Risk of Off-Target an iso-octyl ester can reduce volatility by 98.5%. Drift? The drift hazard, or off-target potential of a herbicide in a Size of Area Treated particular situation, depends on the following factors: When large areas are treated relatively large amounts of active herbicide are usually applied and the risk of off-target effects • Proximity of susceptible crops to the particular herbicide being increase due to the length of time taken to apply the herbicide. applied, and their growth stage. For example cotton and Conditions such as temperature, relative humidity and wind canola are more sensitive to phenoxy herbicides at direction can change during spraying. the seedling stage. Capture Surface • The method of application and equipment used – air, ground, Targets vary in their ability to collect or capture spray droplets. mister and their specific configurations can affect off-target drift. Well-grown, leafy crops are efficient collectors of droplets. Turbulent airflow normally carries spray droplets down into the • Size of the area treated and the amount of active herbicide applied. crop within a very short distance. • Efficiency of the capture surface, bare soil versus crop. Fallow paddock or seedling crops are generally poor catching • Volatility of the formulation applied; ester-based formulations are surfaces. Drift hazard is far greater when applying herbicide in recognised as the most volatile phenoxy formulations – changing these situations or adjacent to these poor catching surfaces. to a non-volatile amine or salt formulation reduces risk. The type of catching surface between the sprayed Important Considerations for Avoiding area and susceptible crops should always be Off-Target Drift considered in conjunction with the characteristics of the target area when Reducing Spray Release Height assessing drift hazard. 1. Operate the boom at the minimum practical height. Spray drift hazard doubles as nozzle height doubles. Angling nozzles forward can allow lower boom height with double overlap. Lower boom height can, however, lead to striping if the boom 18

Weather Conditions to Watch Out for: Relative Humidity or Delta T. Inversions The differential between a wet and dry bulb thermometer • The most hazardous condition for herbicide spray drift is an reading is known as “delta T”. Relative humidity is a measure atmospheric inversion, especially when combined with high of the amount of moisture in the air expressed as a percentage. humidity. Relative humidity and dry bulb temperature are used to calculate delta T. • Do not spray under inversion conditions. • An inversion exists when temperature increases with altitude instead of decreasing. An inversion is like a cold blanket of As temperature increases delta T becomes critical in predicting air above the ground, usually less than 50m thick. Air will weed stress. Low relative humidity coupled with high not rise above this blanket, and smoke or fine spray droplets temperatures cause many common fallow weeds to “shut and particles deposited within an inversion will float until the down”. All plants have a self-preservation mechanism which inversion breaks down. often involves wilting and closing of the stomata causing normal functioning in the plant to go into “hibernation”. • Inversions usually occur on clear, calm mornings and nights. Windy or turbulent conditions prevent inversion formation. Blankets of fog, dust or smoke and the tendency for sounds Intensive trial work indicates that a delta T value of 8°C or below and smells to carry long distances indicate inversion is preferable and if the delta T value is greater than 10°C weed conditions. control will be reduced. Relative humidity and temperature can be ®7 • Smoke generators or smokey fires can be used to detect measured with a device such as the Kestrel 3000 weather meter. inversion conditions. Smoke will not continue to rise but will drift along at a constant height under the inversion ‘blanket’. Consult the chart below to determine the best delta T conditions to spray. Midday Turbulence • Up-drafts during the heat of the day cause rapidly shifting wind directions. Avoid spraying during this part of the day. High Temperatures • Avoid spraying when temperatures exceed 28°C. Humidity • Avoid spraying under low relative humidity conditions (less

than 35%) i.e. when the difference between wet and dry X X X bulbs (delta T) exceeds 8°C. X X X • High humidity extends droplet life and can greatly increase X the drift hazard under inversion conditions. This results in X increased life for droplets smaller than 100 microns. X

Wind X • Avoid spraying under still conditions. • Ideal safe wind speed is 3–10 km per hour (kph). Leaves and twigs are in constant motion. • 11–14 kph (moderate breeze) is suitable for spraying if using low drift nozzles and/or higher volume application *It is important to note that ‘off-target drift’, regardless of the (80–120L/ha). Small branches move, dust is raised and type of drift, can be totally avoided through sound application loose paper is moving. decisions and management.

Nufarm Phenoxy Reference Guide www.nufarm.com.au 19

Nozzle Selection Guide for Ground Application

Risk High Medium Low

Distance downwind to susceptible crop <1 km 1 – 30 km >30 km

Droplet size (BCPC & ASAE) coarse medium fine

Recommended nozzles (Examples only) Raindrop - Whirljet® Drift reduction Conventional Air induction- DG Teejet®8 XR Teejet®8 Airmix®11 Turbo Teejet®8 Hardi®9S3110 Yamaho Hardi®9ISO LD 110 Hardi®9S4110 Turbodrop Lurmark Lo-Drift®10 Hardi®9150 F series Hardi®9Injet Lurmark Fan Tip® Al Teejet®8 Lurmark Drift-beta®10 CAUTION Can lead to poor coverage and Suitable for grass control at High proportion of ‘driftable’ lack of control of grass weeds. recommended pressures. droplets. Temperature and Requires higher spray volumes. Some fine droplets. humidity critical.

Nozzle Selection Selecting the correct spray nozzles, pressure, speed, water larger, and the percentage of droplets less than 200 microns volume and spray release height are key factors impacting on (droplets most susceptible to drift) was also conducted. product performance. Changing to nozzles that produce a The data indicate that a shift in spray quality from fine to coarse medium to coarse spray quality is one way to minimise was obtained. The VMD varied from 213µm for the XR Teejet®8 off-target spray loss. nozzle (XR) to 333µm and 353µm for the TurboTeejet®8 (TT) and An independent trial conducted in a wind tunnel by the Centre Airmix®11 nozzles (AM) respectively. The driftable component for Pesticide Application demonstrated the difference in spray was reduced from 44% for the XR to 18% (TT) and 11% (AM). quality that can be achieved by changing the nozzle setup on Although there has been a reduction in the driftable component a spray boom when using phenoxy herbicides. Surpass® 300 by changing nozzles, other parameters, such as release height, was applied through XR Teejet®811002, Turbo Teejet®811002 speed, pressure, water volume and meteorological conditions and Agrotop Airmix®11110-02 nozzles at the same pressure need to be considered when making a decision to spray. Drift (200kPa) and water volume (50L/ha). Measurement of the reduction nozzles are available, including pre-orifice and air volume mean diameter (VMD), which is the figure in microns induction nozzles, from local suppliers. where half the spray droplets (by volume) produced by the nozzle are smaller than this size and half are

Nufarm ® 300

(µm) µm µm 20

Herbicide Resistance Management Herbicide resistance is the inherent ability of a weed to survive Aim to: a herbicide rate that would normally control it. This is not the • Reduce weed numbers by preventing seed set. same phenomena as poor herbicide performance. • Enter a cropping phase with low weed numbers. Why it is a Problem? • Use as many different control options (chemical and non- If herbicide resistance develops, other herbicides or different chemical) as possible in both crop and pasture phases. control methods will have to be used to control a weed. These When Using Herbicides: options may be more expensive or less effective. Once developed, herbicide resistance will persist for many years. • Rotate herbicides from different groups. • Reduce reliance on high-risk herbicides (Groups A and B) Understanding Herbicides • Make every herbicide application count – use the rate that Herbicides act by interfering with specific processes in plants. gives effective control. This is known as the herbicide’s ‘mode of action’. Phenoxy Resistance Management Watch your Paddocks For weed resistance management phenoxys are Group I • Keep accurate records. herbicides. Some naturally occurring weed biotypes may be • Monitor weed populations and record results of herbicides used. resistant to Group I herbicides through normal genetic • If a herbicide does not work, find out why. variability in any weed population.

• Check that weed survival is not due to spraying error. Resistant individuals can eventually dominate a population if • Conduct your own paddock tests to confirm herbicide failure the same group of herbicide is used repeatedly. and what herbicides are still effective. These resistant weeds will not be controlled by Group I • As soon as herbicide resistance is detected, prevent seed set. herbicides. • Have a herbicide resistance test carried out on seed from suspected plants testing for resistance to other chemical groups. • Do not introduce or spread resistant weeds in contaminated grain or hay.

Know Your Herbicide Groups

High Risk Group A Inhibitors of fat (lipid) synthesis - ACC'ase inhibitors Group B Inhibitors of the enzyme acetolactate synthase - ALS inhibitors Moderate Risk Group C Inhibitors of photosynthesis at photosystem II Group D Inhibitors of tubulin formation

Group E Inhibitors of mitosis Group F Inhibitors of cartenoid biosynthesis Group G Inhibitors of protophyrinogen oxidase Group H Inhibitors of protein synthesis Low Risk Group I Disruptors of plant cell growth (Phenoxy herbicides) Group J tba

Group K Herbicides with multiple sites of action Group L Inhibitors of photosynthesis at photosystem 1 Group M Inhibitors of EPSP synthase Group N Inhibitors of glutamine synthetase

Source: ‘Weed Control in Winter Crops 2004’, NSW Agriculture.

Nufarm Phenoxy Reference Guide 21 Notes 22

Nufarm Phenoxy Reference Guide www.nufarm.com.au 23 For more information contact your Nufarm Regional Office: Northern Region QLD/NSW (07) 3893 8777. Southern Region VIC 1800 033 038 SA (08) 8444 6300. Western Region WA (08) 9411 4000.

®: Registered Trademark of Nufarm Australia Ltd. TM: Trademark of Nufarm Australia Ltd. TM1: Roundup PowerMAX is a registered trademark of Monsanto technologies LLC used under licence by Nufarm Australia Ltd. ®1: Registered Trademark of BASF Ltd. used under licence by Nufarm Australia Ltd ®2: Registered Trademark of Syngenta Ltd. ®3: Registered Trademark of Ltd. ®4: Registered Trademark of Dow AgroSciences Ltd. ®5: Registered Trademark of Nissan Chemical Industries Ltd. ®6: Registered Trademark of Arysta LifeScience Corp ®7: Registered Trademark of Nielsen Kellerman Australia Pty Ltd. ®8: Registered Trademark of Spraying Systems Company Ltd. ®9: Registered Trademark of Hardi International Ltd. ®10: Registered Trademark of Lurmark Ltd. ®11: Registered Trademark of Agrotop Ltd.

This publication is a guide only and no substitute for professional or expert advice. The product label should be consulted before use of any of the products referred to in this publication. Nufarm Australia Ltd shall not be liable for any results, loss, or damage whatsoever, whether consequential or otherwise, through the use or application of products and/or materials referred to herein.

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