CANOLA WEED MANAGEMENT Eric P Prostko and Tim

CANOLA WEED MANAGEMENT Eric P. Prostko and Tim L. Grey Extension Weed Specialist and Research Weed Scientist The University of Georgia April 2007

Before Getting Started Ø What herbicides were used in previous crops? Ø Canola is very sensitive to herbicide residues!!

Canola Rotation Restrictions Herbicide Canola Plant-Back Atrazine 12 months Accent 10 months (≤ 6. 5 p. H) Cadre Classic 40 months 0 (? ) months (Clearfield) 18 months Direx 24 months Envoke 18 months + FB Reflex 18 months Staple 10 months + FB Strongarm 30 months + FB Valor 12 months + FB FB = Field Bioassay

Avoid Planting Canola in Wild Radish/Mustard Fields

Follow All UGA Recommended Production Practices Ø Adapted Variety Ø Planting Date – North Zone (September 10 to October 25) – South Zone (October 10 to November 15) Ø Ø Ø Row Spacing (6 -12”) Seeding Rate (4 -6 lbs/A) Fertility Management

Herbicides For Use in Georgia Canola Ø Glyphosate – at-planting but before crop emergence Ø Treflan, Trilin, etc. – PPI Ø Select/Arrow, Poast, Assure/Targa – POST (grass control) Ø Beyond – POST – Clearfield varieties only!!!!

Trifluralin in Canola Ø Incorporate to depth of 23” within 24 hours of application Ø 2 -pass system Ø 0. 50 -0. 75 lb ai/A Ø some control of winter annual grasses, henbit, and chickweed Ø no control of wild radish/mustard Ø Better than nothing!

Ø Clearfield Canola Production Systems Ø Non-GMO Ø Beyond (imazamox) is only herbicide registered for use in U. S. Ø Based on UGA field trials, eliminates concerns for Cadre (imazapic) carryover problems. However, Clearfield canola is NOT listed on Cadre label.

Ø Ø Ø Clearfield Canola varieties only!!!!! Beyond 1 AS (imazamox) 4 oz/A + NIS @ 0. 25% v/v + UAN @ 2. 5% v/v weeds less than 3” tall In UGA field trials, Beyond has provided good to excellent control of Italian ryegrass, wild radish and shepherd’s-purse when applied between 24 and 37 DAP. Ø $515/gal ($16. 09/A)

Ø ROTATIONAL CROP RESTRICTIONS FOR BEYOND Ø 3 months = wheat Ø Ø Ø 4 months = barley, rye 8. 5 months = field/sweet corn 9 months = cabbage, cantaloupe, carrot, cotton, cucumber, grain sorghum, oats, onion, peanut, pepper, tobacco, tomato, turnip, watermelon Ø 18 months = non-Clearfield canola

Weed Control in Clearfield Canola with Beyond 1 AS (4 oz/A) + COC (1% v/v) + 37% UAN (2 qts/A) Weed Timing 2001 -2002’ 2002 -2003’ Average Wild radish 24 DAP 94 98 96 37 DAP 94 98 96 Italian ryegrass 24 DAP 75 90 83 37 DAP 69 90 80 Henbit 24 DAP 86 74 80 37 DAP 68 74 71 Shepherd’spurse 24 DAP 99 90 95 37 DAP 99 91 95 Wild garlic 24 DAP 60 92 76 37 DAP 60 94 77 Grey et al. 2006. Weed Technology 20: 551 -557

Stinger Ø Ø Ø Ø clopyralid labeled but not yet recommended by UGA 3 lb ai/gal 4 -8 oz/A ($15 -30/A) 2 to 6 leaf stage of canola 50 day PHI Canada thistle, sowthistle, dandelion, chamomile Rotations – 0 months = field corn, wheat, barley, oats – 10. 5 months = grain sorghum, onions, sunflowers – 18 months = all other crops

Other Types of Herbicide. Resistant Canola Ø Roundup-Ready (RR) Ø Liberty-Link (LL) Ø both are not currently labeled for use in Georgia Ø Why? – Developed after Georgia stopped growing canola on a commercial basis – varieties more susceptible to blackleg – volunteer problem in other RR crops – herbicide resistance issues

Weed Control in RR-Canola with Roundup Weathermax 5. 5 SL (22 oz/A) Weed Timing 2001 -2002’ 2002 -2003’ Average Wild radish 24 DAP 79 90 85 37 DAP 96 90 93 Italian ryegrass 24 DAP 83 90 87 37 DAP 90 91 91 Henbit 24 DAP 73 90 82 37 DAP 95 91 93 Shepherd’spurse 24 DAP 99 90 95 37 DAP 99 92 96 Wild garlic 24 DAP 61 90 76 37 DAP 78 90 84 Grey et al. 2006. Weed Technology 20: 551 -557

Weed Control in LL-Canola with Liberty 1. 67 SL (34 oz/A) + 21% AMS (3 lb/A) Weed Timing 2001 -2002’ 2002 -2003’ Average Wild radish 24 DAP 55 41 48 37 DAP 55 25 40 Italian ryegrass 24 DAP 69 60 65 37 DAP 76 45 61 Henbit 24 DAP 55 66 61 37 DAP 81 58 70 Shepherd’spurse 24 DAP 79 60 70 37 DAP 99 30 65 Wild garlic 24 DAP 55 81 68 37 DAP 74 86 80 Grey et al. 2006. Weed Technology 20: 551 -557

UGA Weed Science www. gaweed. com