Sakura 2013 review and SclerotiniaMIG crop updates

Rick Horbury – Technical Advisor north

SAKURA pre-emergent herbicide:

Registered for use in wheat (not durum wheat) and triticale at 118 g/ha.

Registered for control or annual ryegrass, barley grass, silver grass, annual phalaris, and toad rush.

Registered for suppression of brome grass (great brome only) and wild oats.

Sakura is a Group K herbicide containing the active ingredient pyroxasulfone.

Sakura can be applied up to 3 days before incorporation.

Sakura provides prolonged residual soil activity under good soil moisture conditions.

Sakura works primarily through root uptake.

Sakura® is a Registered Trademark of Kumiai Chemical Industries Co. Limited

http: www.sakuraherbicide.com.au

Sakura at a glance:

SAKURA - the positives in a patchy start:

• Sakura applied prior to dry sowing generally performed well. i.e. pre 7th May 2013 seeding.

• Sakura applied from late May onward activated in July with the germinating weeds providing good control. i.e. Mukinbudin

• Sakura activated after July rainfall and controlled later emerging grass weeds, even where some of the early weeds had escaped.

• Sakura + trifluralin mixtures worked well under a drying top soil (“The Grey Zone”) 10-20th May.

http: www.sakuraherbicide.com.au

Understanding stubble & soil binding of pre-emergent herbicides used for ryegrass control in winter cropsToday’s presenter is: Dale Shaner, USDA (retired)GRDC Webinar 13/12/13

Release of herbicide from surface residue with rainfall:• Trifluralin and prosulfocarb are not washed from residue surface with rainfall.• Metolachlor, dimethenamid and pyroxasulfone can be washed from surface

residue.

5 mm 10 mm 15 mm0

10

20

30

40

50

60

70

80

90

% pyroxasulfone (Sakura) washed from residue after rainfall

% w

ash

ed o

ff

The impacts of stubble without following rain are an issue for ALL pre-emergent herbicides

Use high water rates if the stubble cover is likely to be problematic

Prostrate stubble

Standing stubble/

furrow concentration

Pasture - compacted

SAKURA: Importance of rainfall after sowing

Dry soil – awaiting activation

Dry top soil,

moist below

Sakura – effective application video

Moist soil and incorporated

http: www.sakuraherbicide.com.au

Actively growing weeds but inactive herbicide = reduced performance

The impacts of stubble without following rain are an issue for ALL pre-emergent herbicides

Use higher water rates if the stubble cover is likely to be problematic

Prostrate stubble Standing stubble/

furrow concentration

Pasture - compacted

2013 Key factors influencing performance:

Seed bank (high density), especially coming out of pasture in 2012. Stock pulverising stubble and pushing weed seeds into soil profile.

Following a germination event 2-10 days after spray application & seeding. “The Grey Zone”

Stubble (not washing through) in time to be active in the soil where weeds are germinating.

Insufficient rainfall within 7-10 days after application to facilitate movement of Sakura into the weed seed zone ( top 2.5 to 3 cm).

http: www.sakuraherbicide.com.au

Sakura needs to be “Present for the Germination event”

SAKURA: GETTING THE BEST POSSIBLE RESULTS

The checklist:

Use Sakura in rotation with other chemical and non-chemical control options

Mix Sakura in the tank first (pour slowly) and ensure it is fully dispersed before adding other productsMaintain good agitation before and during spraying.

Apply Sakura at full label rates

Apply Sakura evenly to uncultivated soil that isn’t too ridged or cloddyCultivation before Sakura application (including “tickle”) will bury weed seeds, or stimulate increased emergence.

Use high water rates if the stubble cover is likely to be problematicStubble cover or other plant residues of greater than 50% can reduce the effectiveness of Sakura.Pulverised pasture stubble ‘blanketing’ the paddock or only partially burned windrows will be more problematic than crop stubble, even if it’s prostrate.

Ensure emerged weeds are controlled by an effective knockdown herbicide before planting the crop

Sakura needs to be present when weeds germinate for most effective uptake Sakura works well for dry seeding, but control will be compromised if Sakura is applied onto moist soil without follow-up rain. For application after a weed germination event with minimal rain forecast, tank-mixing with trifluralin may improve control.

Incorporate Sakura by sowing (IBS) using either knife points and press wheels or narrow points and harrows within 3 days of application

http: www.sakuraherbicide.com.au

Subline in Arial bold, 18ptPractice Integrated Weed Management to extend the life of all chemistry

Things we know about sclerotinia in canola

What do we face?• Canada typically flower for 4-5 weeks, Australia 6-8+ depending on

variety.• All canola varieties are susceptible and bigger healthier canopies

can increase the risk.• Liquid N fertiliser applications during flowering may increase severity

of the disease (increasing canopy bulk).• Main stem infections cause greater yield loss than lateral ones.The disease:• Sclerotes survive for long periods in the soil (~6 years).• When the soil temperature is ~15°C and soil becomes saturated

apothecia will emerge in 7-10 days and will keep emerging while conditions are favourable (high humidity).

• A single sclerote can produce up to 15 apothecia.• Optimal temperature for lesion development is 20-25°C with

primary infection generally from petals but secondary infection can occur from contact with infected leaves or stems.

• Sclerotinia needs 24-36 hours of continual leaf wetness to infect.

Assessment of flowering stages

Flowering stages should be assessed on the main stem:

10% = 10 flowers open20% = 14-16 flowers open30% = 20 or more flowers open40% = 30 or more flowers open50% = All flowers are open or have opened, crop is at its most intense yellow (full flower)60% = Flowering intensity is beginning to decline

http: www.bayercropscience.com.au or Think twice – Sclerotinia”

Mean

Henty

(NSW

)

Dookie (V

ic)

Wag

ga W

agga

Dookie (V

ic)

12 Chapman

Valley

(WA)

Howlong (Vic)

Howlong (Vic) Vic

Junee (N

SW)

Dookie (V

ic)

11 Rudd's Gully

(WA)

11 Chapman

Valley

(WA)

11 Chapman

Valley

(WA)

13 Geraldton (W

A)

13 Green Ran

ge (W

A)

11 Straw

berry (

WA)

Tarcu

tta (NSW

)

Boorowa (

NSW)

Cowra (N

SW)

13 Narngu

lu (WA)

Henty

(NSW

)

Holbrook (

NSW)

Dookie (V

ic)

Burrumbuttock

(NSW

)

Walb

undrie (N

SW)

90

100

110

120

130

140

150

160

170

180

118

100 102 102 103 104108 109 110

112 114 114 116 116118 119 120 121 122

126 127

136 138 139 139

172

% u

ntre

ated

yie

ld

2011-13 Prosaro control of sclerotinia in canolaAverage % yield increase over untreated (100% = 1.90 t/ha)

18% average yield increase (350 kg) over untreated across 25 commercial trials.

http: www.bayercropscience.com.au or “Think twice – Sclerotinia”

Economic return at ~$500 tonne

1st 5th 9th13th

17th21st

25th29th 2nd 6th

10th14th

18th22nd

26th30th 3rd 7th

11th15th

19th23rd

27th0

5

10

15

20

25

30Geraldton airport daily rainfall and max. daily temp.2013

rain

fall

mm

/ te

mpe

ratu

re °C

July August September

Spray timings – spray to the conditionsProsaro yield response in the Midwest13WE02: Control of Sclerotinia in Hyola 404RR, Narngulu, WAApplication (25/7) = 30% flower

Location Narngulu

Variety Hyola 404RR

Flowering length 6-8 weeks

Yield t/ha response

320 kg/ha$125.85 ROI

Key messages:• Apothecia found on 25th July• 30% spray resulted in 27% yield response• 2 spray strategy starting at 30% ~3 weeks

apart may have provided improved yield

Protection period~3 weeks

Apothecia

Treatment 03/10/2013

% Incidencet/ha

% untreated

Costs $/ha% Oil

gross $/ha

ROI $/ha % Sclerotes by weight

Untreated 53 a 1.19 100   45.2 $604.14   0.44

Prosaro 375 mL/ha 14 b 1.41 118 $26.25 45.4 $712.97 $76.58 0.08

Prosaro 450 mL/ha 7 b 1.51 127 $29.70 45.8 $764.70 $123.06 0.1

http: www.bayercropscience.com.au or “Think twice – Sclerotinia”

Prosaro significantly reduced disease severity and incidence to maintain yield potential.

Fungicides: Getting the best results for sclerotinia in canola

The checklist:

Single spray:If opting for a single spray don’t apply too early. The best timing is generally ~20-30% flowering dependent on conditions.Later application at 30-50% timings can be beneficial in longer seasons.

Other considerations:Air / soil temperature and rainfall are as important as flowering stage.Increased water rates are recommended – 100 L/ha is good.When plants are fast growing the window of protection will be shorter i.e. at 20% compared to 40% flowering.

Multiple Sprays:Longer flowering varieties may require 2 applications under high disease pressure.Spray timings should consider favorable conditions for disease development not just

crop stage.

Future developments: Bayer CropScience continues to evaluate new chemistry for sclerotinia control.

http: www.bayercropscience.com.au or “Think twice – Sclerotinia”