Weed management for California rice

Transcription

1 Weed management for California rice Albert Fischer with James Eckert & Whitney Brim DeForest Weed Science Program University of California - Davis

2 Sedges & broadleafs Photo source: UC Statewide IPM

3 Grasses E. phyllopogon Leptochloa fascicularis Photo source: UC Statewide IPM

4 Effect of rice culture on weed competition Weed Control by the end of 40 days after seeding Yield (%) Continuous flood Pin point Drill seeded Y= x X; R 2 =0.43 Y= x X; R 2 =0.55 Y= x X; R 2 = Weed control (%)

5 Continuously flooded system The system maximizes weed suppression by flooding: elimination of barnyardgrass and sprangletop Water seeding and flood maintained at 4-5 in

6 Permanent Flood (use granular herbicides into the water at early stages, then lower the water to spray foliar herbicides onto weeds) Flood, Seed 1LSR 3LSR Tiller initiation Tillering Panicle initiation Flowering 2.5LSR Possible Treatments Cerano or Bombard (by Cheminova); (DOS 1.5 lsr) Bolero Ultramax (1-2 lsr) Granite GR (2-3 lsr) Shark H 2 O or Londax, Sandea or Halomax 75 (2-3 lsr) League MVP (thiobencarb + imazosulfuron) (2-3 lsr) Possible Treatments Propanil (or propanil + Grandstand) Regiment Clincher Butte (benzobicyclon + halosulfuron) (1 lsr) Clincher Granule (2-3 lsr)

7 Early-drain systems Water seeding When one needs to drain for rice establishment and/or to apply foliar treatments

8 Early Drain-foliar (Pin-point Flood/Leathers ): Drain to spray weeds while they are small; Then lower water to expose weed foliage to second spray) Possible treatments Clincher (2-3 lsr) Propanil + Clincher (2-3 lsr) Granite SC (2-3 lsr) Clincher + Granite SC (2-3 lsr) Regiment+Abolish (3-4 lsr) Foliar herbicides Rice 2-3 lf Reflood to 3 in Follow-up herbicides Treatments Propanil Propanil+Grandstand Regiment Rice 3 lf 1-3 Tiller Flood, Seed 2LSR Tiller initiation Tillering Panicle initiation Flowering

9 Early Drain (Leathers )- granule: for granular herbicides into the water after reflood Seed (Day 1) Begin drain (about Day 5) Water back on (Day 10) Granular herbicides (Rice 1 2 lf) Cerano (12 lb) Granite GR Treatments New under testing Benzobicyclon + halosulfuron (Butte ; Gowan ) 2 nd leaf Follow-up Treatments Propanil, Grandstand Regiment Clincher

10 Drill seeded Flexibility for herbicide use in drift-risk areas Facilitates ground-rig applications Favors weeds adapted to dryland seedbeds (barnyardgrass, sprangletop) Less favorable to aquatic weeds (ricefield bulrush, ducksalad, redstem) Useful for alternation with water-seeded systems

11 Drill-seeded (field is initially dry and then is gradually flooded deeper) Seed (Day 1) Delayed PRE after establishment flush, rice fully imbibed Early Post emergent (2-4 lsr) Post permanent flood (Day 7) 2-3 Lsr 3-4 Lsr (Day 25) Permanent Flood Day 3 Day 9 Day 21 Flush irrigation

12 Drill-seeded (field is initially dry and then is gradually flooded deeper) Delayed PRE Possible treatments Prowl H2O Abolish Early POST (2-4 lsr) Possible treatments Prowl+propanil+Clincher Prowl+Granite+Clincher Clincher+Granite Clincher followed by propanil Propanil (after Prowl orabolish DPRE) Late POST Possible treatments propanil Clincher (Day 7) 2-3 Lsr (June 22) 3-4 Lsr (June 29) Permanent Flood Day 3 Day 9 Day 21 Flush irrigation

13 SUSCEPTIBLE The Late Watergrass resistance issue control Clincher Regiment propanil Granite RESISTANT a.k.a. Mimic

14 SUSCEPTIBLE SUSCEPTIBLE Also the Early Watergrass species control Clincher Regiment propanil Granite RESISTANT a.k.a. the early form

15 1. Control escapes (even if late in the season: prevent weed seeding)

16 2. Tank mixes (different modes of action and synergism)

17 3. Sequentials (different modes of action)

18 The new resistance issue: Smallflower umbrella sedge UTC ¾ X Stam 1½ X Stam Londax Sandea Shark H 2 O

19 A popular program that worked well Into-water herbicides for ghrass control propanil germination 5 lsr tillering panicle flowering initiation

20 Now multiple resistant to propanil and Londax UTC ¾ X Stam 1½ X Stam Londax Sandea

21 Smallflower cross- resistance testing Foliar applied Herbicides: 1. Untreated control 2. Stam 6726 g ai/ha 3. Londax 70g ai/ha 4. Granite SC 35g ai/ha 5. Shark H2O 224g ai/ha 6. Sandea 52.5g ai/ha 7. V g ai/ha

22 Smallflower cross- resistance testing Herbicide Susceptible (HR) Pop. #4 Pop. #3 Pop. #6 Pop. # %Control Stam 99 a 7 cdef 26 bcdef 63 abcdef 37 abcdef Londax 95 a 0 f 0 f 46 abcdef 64 abcdef Granite SC 98 a 78 abcdef 79 abc 85 ab 86 ab Shark 100 a 100 a 100 a 100 a 100 a Sandea 95 a 46 abcdef 16 bcdef 88 ab 97 a Imazosulf. 100 a 14 bcdef 68 abcde 73 abcd 95 a =Resistant =moderately R

23 Smallflower cross- resistance testing Herbicide into-water treatments: 1. Untreated control 2. Bolero 3918g ai/ha (23.3 lb/a) 3. League MVP 2923g ai/ha (25 lb/a) Growth stage at treatment Untreated Bolero League MVP

24 Riecefield bulrush propanil resistance & cross-resistance

25 Riecefield bulrush propanil resistance & cross-resistance Population# S Stam 71 ABCD 61 BCDE 68 ABCD 82 ABC 25 EFG 12 GH Londax 100 A 13 FGH 14 FGH 68 ABCD 67 ABCD 42 DEFG Granite 100 A 82 ABC 98 A 100 A 98 A 98 AB Shark 100 A 100 A 100 A 100 A 100 A 100 A Sandea 100 A 48 CDEFG 50 CDEF 100 A 100 A 100 A Imazosulf. 100 A 100 H 12 GH 100 A 99 A 93 AB

26 Propanil-resistant sedges 2011 Smallflower 2011 Bulrush 2012 Smallflower Yuba City Woodland

27 Herbicide use Management Avoid repeated use of herbicides with the same mechanism of action (MOA) Use different MOAs effective on same weeds mixtures & sequences Avoid low rates: Use labeled rates and change to herbicides of different MOA

28 If you don t have propanil resistant sedge Shark or Bolero Propanil Germination 5 lsr tillering panicle flowering initiation

29 If you don t have propanil resistant sedge Bolero Propanil + Shark by GROUND (!) Germination 5 lsr tillering panicle flowering initiation

30 If you already have propanil resistant sedge Shark or Bolero germination 5 lsr tillering panicle flowering initiation

31 If you already have propanil resistant sedge Bolero Treat escapes with Shark by GROUND (!) gernination 5 lsr tillering panicle flowering initiation

32 Management Maintain low weed infestations Control all weed escapes & late-season flushes Harvest affected checks last Diversify control techniques: Use different ways to kill/suppress the weed rather than just one

33 4. Alternative establishment systems (benefits of rotation in a non-rotated crop)

34 WATER SEEDED Smallflower Ricefield bulr. Redstem Ducksalad Barnyardgrass Sprangletop DRY SEEDED

35 5. Stale seedbed (using a non selective herbicide)

36 Stale seedbed control of multiple herbicide resistant late watergrass ( mimic ) glyphosate 4 5 lsr Spring tillage (could be ommitted) Water seeding tillering Panicle initiation flowering glyphosate 2 3 lsr Spring tillage (could be ommitted) Dry seeding germination tillering flowering