Improving Adoption of IWM Practices for Managing Emerging Weeds in Western Region Abul Hashem, Mohammad Amjad and Catherine Borger Department of

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1 Improving Adoption of IWM Practices for Managing Emerging Weeds in Western Region Abul Hashem, Mohammad Amjad and Catherine Borger Department of Agriculture And Food, Western Australia

2 Acknowledgements GRDC: for funding UA00149 University of Adelaide (Dr Chris Preston): For research collaboration DAFWA Technical officers: C Wild, D Nicholson, N Wilkins, B Sage, P Bartlett DAFWA Technical support units: Wongan Hills, Merredin, Northam and Geraldton Farm Families: Sawyers family, Cook Family, Chivers Family, Critch Family, Carter Family, Scanlan Family, Hill Family, West Family, Royce Family. Growers Groups: Liebe Group, MIG Group, Facey Group. Chemical companies: Adama, BASF, Bayer, Imtrade.

3 Background Changes in Farming systems Farm practices Climate Resistance Changing weed spectrum Summer emerging weeds: button grass, fleabane, sowthistle, tar vine. Winter emerging weeds: Resistant biotypes in winter weed species such as wild radish and brome grass emerging Lack of location specific biology, ecology and control options Slow adoption of IWM for winter emerging weeds

4 Methods Roadside weed surveys 2015, 2016 and resistance testing 7 laboratory and 3 glasshouse experiments to understand biology and herbicide resistance. 2 multi-year small-plot experiments at Merredin and Northam to understand the emerging pattern across seasons. 18 field trials to develop and demonstrate appropriate control practices including IWM for the emerging summer and winter weeds. Extension and communication activities

5 Roadside survey: distribution and resistance of summer emerging weeds February to April of 2015 and 2016 Stop every 10 km along a transect of m Record weed density (seed head or tillers for grass weeds and plant numbers for broadleaf weeds) for each species. Collect mature seed of button grass, fleabane, sowthistle and tar vine.

6 The number of survey sites and the frequency of the four most common weed species in each region. Year Region 2015 Northern agricultural region Number of sites 49 Fleabane (65%) Four most common species (and percentage frequency) African lovegrass (47%) Couch (35%) Wild radish (29%) Central agricultural region 140 African lovegrass (43%) Windmill grass (30%) Wild radish (29%) Fleabane (29%) Southern Agricultural region 54 African lovegrass (65%) Fleabane (46%) Sowthistle (41%) Windmill grass (39%) 2016 Northern agricultural region 16 Windmill grass (63%) African lovegrass (50%) Wild radish (44%) Mullamulla (44%) Central agricultural region 89 African lovegrass (70%) Windmill grass (49%) Wild radish (48%) Roly poly (33%) Southern Agricultural region 33 African lovegrass (79%) Windmill grass (67%) Sowthistle (67%) Fleabane (64%) Total Total wheatbelt African lovegrass (87%) Windmill grass (61%) Fleabane (60%) Wild radish (52%)

7 Survival of sowthistle populations collected from roadside surveys in 2015 to various herbicides Herbicide Rate (g/ha) Number of populations with survivors Glyphosate Paraquat + diquat 2,4-D E (LVE) Metsulfuron >21 4

8 Effect of herbicides on the seed production of sowthistle Herbicides Rate (g ai/ha) Reduction in cepsela in treatments (%) Glass house Outdoor Roundup Power Max 630 ml 350 g glyphosate Velocity 700 ml Bromoxynil 147 g + 26 g pyrasulfotole Alliance 2L 500 g paraquat g amitrole Untreated - - Untreated: Glasshouse 36 cepsela, outdoor 92 cepsela/plant. about 80 seed/cepsela.

9 Emergence pattern and seed dormancy of summer emerging weeds

10 Germination (as a percent of the total germinable seed) at Merredin, from November 2014 to October Germination (%) Fleabane Sowthistle Tarvine Button grass

11 Effect of bleaching treatment on the seed dormancy release of button grass, fleabane, sowthistle and tar vine Weed species Germination percentage No bleaching Bleaching Mean Button grass Fleabane Sowthistle Tar vine P-Value <.001 LSD

12 Seed germination Effect of different dormancy breaking treatments on button grass seed germination Lsd (5%) for untreated control = 3.93, hot water treatment = 2.85, hydration = 10.08, scarification = 9.78, and sulphuric acid = Dark 52 0 Light 0 16 Untreated Hot water Hydration Scarification Sulphuric acid

13 Field trials to control emerging summer weeds

14 Button grass control (Dactyloctenium radulans) Survey reveals low frequency within WA Wheatbelt Invading northern agriculture region (Mullewa, Wubin) and central agriculture region (Merredin) but slowly moving to south. Button grass can produce ,000 seed/m 2. Up to 45 primary tillers Each of the creeping primary tillers develops roots from nodes into the ground. Seed dormancy is high

15 Field trials to control button grass Glyphosate (Roundup Ultra Max 3L alone or as tank mix with 2,4-D Ester) was highly effective on button grass when applied at seedling and rosette stage during very hot days (40C at Mullewa). Roundup Ultra Max 2.4L followed by Para-Trooper 3L controlled 100% button grass at Nungarin in 2016 season when applied at seed set to seed shedding stage. In contrast, Roundup Ultra Max 2.2L alone, tank mix of Roundup Ultra Max and phenoxy herbicides, or Para-Trooper alone provided 100% control of button grass when applied at seed set stage under mild autumn conditions (<30C at Mullewa).

16 Tar vine (Boerhavia coccinea) control Survey shows low frequency Invading northern and central agriculture regions Can grow up to 1.5 m in diameter Seed has high level of dormancy Boerhavia coccinea B. coccinea B. schomburgkiana

17 Field trials the control of tar vine during summer 2015: 1 trial at Mullewa and 1 at Jennacubbine 2016: 1 trial at Jennacubbine (Northam) Summary of results: Individual herbicide products such as amitrole, glufosinate, saflufenacil, or Lontrel, Starane, Garlon or paraquat-based herbicides provided 52-67% control at Mullewa and 30-85% at Jennacubbine but Roundup Power Max alone provided 82-98% control. Tank mix of glyphosate with Sharpen, Tordon, metsulfuron, glufosinate or double knockdown of glyphosate provided 50 to 100% control. Double knockdown of glyphosate mixed with 2,4-DE followed by Alliance, Spray.Seed or Para-Trooper provided up to 100% control at Jennacubbine.

18 Fleabane control in field during summer season Fleabane (Conyza bonariensis), Asteraceae

19 Fleabane at different stages at Grass Valley in 2014/15.

20 Summary of fleabane control during summer at Grass Valley and Geraldton Application of a mixture of glyphosate and 2, 4-D followed by the application of Spray.Seed was highly effective on fleabane whether applied in December 2014 or March This treatment was also highly effective on couch. Herbicides were more effective on fleabane when applied at seedling or flowering stage than rosette stage

21 Fleabane trial at Geraldton

22 Sowthistle control

23 Control of sowthistle during winter at Geraldton Single application of glyphosate as well as double knockdown (glyphosate followed by Para-Trooper or Spray.Seed ) provided up to 100% control of sowthistle. However, double knockdown is preferred to single knockdown to minimise risks of herbicide resistance development.

24 Windrow burning effect on brome grass seed reduction

25 Windrow burning effect on brome grass seed reduction at Grass Valley Mean brome grass seedling/m 2 in soils collected in autumn Soil collection from windrow treatments Seedlings/m 2 10 cm + trash spread over whole plot cm + windrows (before burning) cm + outside windrows cm + windrows (after burning) 432 ( 93%) P-value <.001 LSD Harvesting a wheat crop at 10 cm high collected 74% of the total viable seed of brome grass into narrow windrows and wind row burning killed over 90% of seed on the wind rows (overall, 70% seed kill).

26 IWM for wild radish management in wheat Mingenew (MIG Group): 2014, 2015 Dalwallinu (Liebe Group): 2014, 2015, 2016 Merredin: 2014, 2015, 2016 IWM for wild radish management in lupin Ballidu (Liebe Group): 2015 Dalwallinu (Liebe Group): 2016

27 Appropriate IWM reduced radish density to zero at Dalwallinu Good control Poor control Good control Poor control Good control Poor control (1-2 knockdowns/high seed rate/ 1 in-crop herbicide) (1-2 Knockdowns/no in-crop chemical or non-chemical option) (1-2 knockdowns/high seed rate/2 in-crop herbicides) (1-2 Knockdowns/no in-crop chemical or non-chemical option) (1-2 knockdowns/high seed rate/ 2 in-crop herbicides) 45 (1-2 Knockdowns/no in-crop chemical or non-chemical option) Radish plants/m 2 (after PO sprays)

28 Conclusions Survey showed emerging weeds are spreading far and wide within WA wheatbelt and emerging weeds are evolving resistance to glyphosate and ALS. Button grass seed is dormant but scarification and hydration reduced dormancy. Fleabane and tar vine seed emerge in summer through early winter but sowthistle can emerge both summer and winter. Tank mix of glyphosate and phenoxy followed by paraquat-based knockdown is effective on most summer emerging weed species. Button grass needs upper label rates of glyphosate (mixture and/or sequence) during hot summer than mild autumn. Herbicides are more effective on fleabane at seedlings or flowering stage than rosette stage. Low cut height, windrowing followed by burning can reduce brome grass population by 70%. IWM including effective in-crop herbicides can reduce wild radish population in three years. Improved adoption of IWM should minimise impact of emerging weeds.

29 Thank you Grains Research and Development Corporation (GRDC) A Level 4, East Building, 4 National Circuit, Barton, ACT 2600 Australia P PO Box 5367 Kingston, ACT 2604 Australia T F #GRDCUpdates