Resistant Weeds in Rice Amy Beth Dowdy NAICC O - lrando January ,

Transcription

1 Resistant Weeds in Rice Amy Beth Dowdy NAICC-Orlando Ol January 21,

2 Resistant weeds are here!

3 Rice weed herbicide resistance in the US Redstem-Bensulfuron Smallflower umbrella sedge- Bensulfuron California Arrowhead- Bensulfuron Ricefield bulrush- Bensulfuron

4 Rice Weed Herbicide Resistance in the US Junglerice-Propanil Barnyardgrass-Propanil, Quinclorac,Clomazone Early watergrass-molinate Molinate, Thiobencarb, Quinclorac Ri b d Rice barnyardgrass- Fenoxaprop,Molinate, Thiobencarb, Bispyribac-sodium

5 Proven resistance by Trade Name Londax- 4 Propanil-2 Facet-2 (Barnyardgrass) Ordram-2 (Barnyardgrass) Bolero-2 2(Barnyardgrass) Ricestar-1 (Barnyardgrass) Regiment-1(Barnyardgrass) Command-1(Barnyardgrass)

6 Herbicide Resistance Current grass herbicides Command - Super Wham Bolero - Rice Star HT Prowl - Clincher Facet - Grasp NewPath - Regiment Number of modes of action Pigment inhibitor - Shoot Inhibitor Root Inhibitor - Growth Regulator ALS Inhibitor - PSII inhibitor ACCase inhibitor

7 Propanil-Resistant Propanil first used in 1959 barnyardgrass Multiple applications on 98% of rice acreage through early 90s Resistance confirmed in of 38 rice counties had propanil-resistant resistant barnyardgrass by 1993 Spread Screening program/educational efforts Facet became solution for propanil-resistant resistant barnyardgrass

8 Propanil-Resistant Barnyardgrass 4 qt/a Stam; Resistance Confirmed Susceptible Resistant 9 days after treatment

9 Facet-Resistant Barnyardgrass Facet first used in 1992 (Section 18) For control of propanil-resistant resistant barnyardgrass Widely used in mid- to late 90 s on most acreage Facet/propanil-resistant resistant barnyardgrass confirmed in 1999 Command solution for Facet-resistant barnyardgrass

10 Command-Resistant Barnyardgrass Command registered in 2000 Used on 70 to 80% of acreage Only herbicide used on some fields Resistance confirmed in 2007 and additional site confirmed in 2008 in Arkansas 2007: Could not control escapes with other herbicide (due to size) 2008: At least 6 years of continuous rice (Command only herbicide applied) Is Clearfield rice the solution?

11 Resistant Barnyardgrass Command resistance a concern Currently isolated, 2 locations confirmed Must not allow escapes! 0.8 pt/a Command

12 Resistant Barnyardgrass Suspect Accase resistance as well (RiceStar and Clincher) in several fields. Currently not confirmed in Arkansas. Sprangletop has been confirmed in Louisiana. i

13 Propanil Facet Command Barnyardgrass (Global Resistance) ALS herbicides ACCase herbicides (fops & dims) Glyphosate

14 What tools do we have today for Command Facet Prowl Bolero Propanil Clincher RiceStar Grasp Regiment Newpath Beyond Barnyardgrass

15 What tools do we have today for resistant-barnyardgrass Command Facet Prowl Bolero Propanil Clincher RiceStar Grasp Regiment Newpath Beyond

16 Clearfield Rice In Arkansas in 2008 of 1.6 million acres there were 70% of those acres planted to Clearfield Newpath is an ALS. Resistance of some weeds to other ALS chemistries has already been shown. Outcrossing of CLF rice with red rice is occurring. CLF tolerant red rice is confirmed.

17 CL Hybrid Rice Shattering Clearfield out-crossing Hybrids Conventional lines Clearfield concerns We have had out-crossing We have naturally occurring ALS tolerance Are we creating the need for new chemistry?

18 conventional phenotypes F1 CL161

19 Hybrid phenotypes Hybrid F2 s

20 Managing shattered or outcrossed fields Flood them for the geese! Kill first flush with tillage Rotate Clearfield fields and hybrid fields with soybeans Use Roundup Up or graminicide.

21 Cultural Weed Control Any non-chemical weed control Production practices Variety Selection Crop rotation Tillage Water management Clean equipment

22 Herbicide Resistance ROTATE! Rotate Crops Rotate MOA Tank Mix

23 Thank you! Bob Scott-Cooperative Extension Service, University of Arkansas Frank Carey-Valent

24 Questions?