MANAGING WEED RESISTANCE IN WESTERN CANADA RECOMMENDED STRATEGIES

Transcription

1 MANAGING WEED RESISTANCE IN WESTERN CANADA RECOMMENDED STRATEGIES

2 Herbicides and Weed Resistance Weed resistance to herbicides is a global problem and one that is of increasing concern to western Canadian growers. Herbicides work to control weeds by disrupting a specifi c biological process within the weed. Resistance starts when the weed undergoes a genetic mutation that changes that process. Through repeated use of the same mode of action the resistant weeds are selected for in the population, reducing the effectiveness of the herbicide. Once resistance is present in a fi eld, repeated application of a herbicide from the same group of chemistry and mode of action controls only the susceptible weeds. The resistant weeds, being immune, will build up in numbers and continue to spread until they dominate the fi eld. The herbicide becomes less effective in controlling that weed population, until it eventually provides little or no control of that weed type. Resistant Weeds in Western Canada Herbicide resistance is present in three western provinces. Weed species such as Wild oat, Wild mustard and Green foxtail have become resistant to multiple groups of chemistries. In addition to Group 2 resistance, recently Group 9-resistant Kochia has been found in southern Alberta. Consequences for Growers Once a fi eld is infested with a resistant weed, it makes farming that ground trickier and often more expensive. Toss in the need to control volunteer crops, many of which can be herbicide tolerant, and management becomes more diffi cult. A single herbicide-resistant weed can limit your rotation and crop choices as you lose the ability to control the weed with your normal herbicide choices. Robert Hornford, Technical Specialist with BASF Canada The consequences to growers of not managing resistance can be severe: Direct losses in both yield and quality as a result of uncontrolled weeds. Increased herbicide use with higher rates and multiple herbicides needed to maintain control, resulting in higher costs. Options for weeds control are reduced, as herbicides become less effective over time due to resistance. Growers need to respect resistance and the threat it poses. They need to be proactive, to manage, and reduce their resistance risk, especially for such a key herbicide as glyphosate. Use of multiple modes of action is a key strategy to delay the development of resistance. Dr. Hugh Beckie, Agriculture and Agri-Food Canada Things to consider for managing resistance The herbicide s group of chemistry. Herbicides using similar active ingredients and modes of action are grouped. A weed may develop resistance to one Group in which case another Group with a different mode of action that targets the weed should be used. Using effective multiple modes of action on the weed provides the best solution. The weed species targeted by the herbicide. Different herbicides target different spectrums of weed species. Overlapping weed spectrums, with two different herbicides using at least two different modes of action from different Groups, is important for managing resistance. The location of the resistant weed. Initially, resistance may be confi ned to a weed population in a specifi c location. However once resistance is present it remains present and growers must be careful in preventing its spread both within the fi eld and to other fi elds.

3 Resistance management strategies 1. Use multiple modes of action on weeds, and tank-mix products whose spectrums overlap. Resistance to one mode of action can usually be controlled by an alternative mode of action. Diversify your herbicides to include a mix of application windows with a variety of herbicide products and modes of action. 2. Use appropriate cultural control methods within an agronomically sound crop rotation. Rotate both the crop and the herbicide Group used in a fi eld. Select vigorous and competitive crop varieties. Seed at an optimal rate, decrease row spacing and seed early, to outcompete weeds. 3. Rotate herbicides where possible. Herbicides used in rotation should come from different Groups with different modes of action. Crop rotation provides the opportunity to rotate herbicides. 4. Use full label rates of herbicide. Lowering the rate is not effective in consistently controlling weeds. Combine this with repeated use of one mode of action increases the risk of weed resistance. 5. Control weed escapes before they go to seed. Prolifi c seed-producing weeds, such as Kochia, have a greater chance of spreading. Controlling weeds before they set seed reduces the chance of spreading resistance if it is present. Tank-mixing to provide multiple modes of action in pre-seed, chemfallow and post-harvest applications, preferably with residual control, helps reduce secondary weed problems and control weeds before they set seed. 6. Use certified seed and be aware of sources of weed seed. A single weed can produce tens of thousands of seeds. The greater the weed seed numbers, the greater the chance for spreading resistance if it is present. At seeding, use clean certifi ed seed. Cover grain during transport. Clean equipment of any weed debris before moving to another fi eld. Keep accurate records to track down sources of weeds. 7. Give your crops an early advantage with cleaner fields. Seed your crop early in a weed-free fi eld to give it a competitive advantage over weeds. Tillage or a pre-emergence burndown will help control early emerging weeds, allowing your crop to develop in a weed-free fi eld. 8. If you suspect resistant weeds, get them tested and stay informed. If weed patches are not affected by a herbicide that has provided control in the past, follow up with the herbicide manufacturer to rule out resistance. Weed pressures, weed resistance and the development of new chemical controls change every year. What worked well in the past may not be the best for today. Reach out to retailers, professional agronomists, extension staff and others as a resource to establish an integrated weed management plan.

4 BASF is committed to sustainable weed control BASF Canada is committed to bringing new innovative chemistry for crop protection that aids growers in producing profi table crops. Herbicide sustainability is a key component of this commitment, both through providing herbicides with new and alternative chemistries, and by offering best management practices to maintain the effectiveness of current and new control solutions into the future. The BASF glyphosate top-up portfolio offers two products designed specifi cally to complement the action of Roundup Transorb HC in pre-emergent, chemfallow and post-harvest applications. HEAT herbicide and DISTINCT herbicide add to the effi cacy of a Roundup Transorb HC application, and also provide alternative modes of action to aid in glyphosate-resistance management. HEAT herbicide for pre-seed, pre-emergence, and chemfallow Group 14 chemistry HEAT uses alternative Group 14 chemistry that complements Roundup Transorb HC (Group 9 chemistry) to provide improved, broad-spectrum control of weeds, including glyphosateresistant and Group 2-resistant biotypes. HEAT tank-mixed with Roundup Transorb HC provides multiple modes of action for early weed control making it part of a sound resistance management strategy. Control performance 100 HEAT + Roundup Transorb HC Competitor Control % Dandelion Narrow-leaved hawk s beard Volunteer canola (all types) Kochia (including resistant biotypes) Wild buckwheat Comparison of weed control 4 days to 2 weeks after application. Source: AgSolutions Performance Trials, 2009, N=97 Untreated HEAT Kochia before and 7 days after an application of HEAT plus Roundup Transorb HC.

5 NEW DISTINCT herbicide for chemfallow and post-harvest applications Group 4 and Group 19 chemistry DISTINCT can be tank-mixed with Roundup Transorb HC to provide alternative modes of action for an improved level of control over Roundup Transorb HC alone. The tank-mix delivers exceptional weed control that includes superior perennial weed control as well as control of Group 2-resistant and glyphosate-resistant broadleaf weeds. In addition, an application of DISTINCT + Roundup Transorb HC post-harvest can help eliminate seed set of resistant weeds like Kochia that can often produce seed after harvest. A post-harvest application is also an excellent time to control emerged winter annual weeds like Narrow-leaved hawk s beard, Winter annual cleavers, etc. DISTINCT also provides maximum follow-crop fl exibility the following season. Chemfallow performance DISTINCT plus Roundup Transorb HC provides superior control in chemfallow applications. 100 DISTINCT + Roundup Transorb HC Dicamba at 2.5 oz/acre Glyphosate Control % Kochia n=8 Buckwheat n=7 Mallow (n=3) Comparison of weed control in chemfallow applications. Source: BASF Research Trials, Lamb s Quarters (n=5) Post-harvest performance For post-harvest, DISTINCT plus Roundup Transorb HC provides superior control that includes Kochia, to provide cleaner fi elds in the following season. Canada thistle Dandelion Kochia DISTINCT plus Roundup Transorb HC provides broad-spectrum weed control. Source: AgSolutions Performance Trials, 2011 Untreated DISTINCT + Roundup Transorb HC + MERGE Weed control in spring following previous September application. Source: BASF Research Trials Monsanto along with Agriculture and Agri-Food Canada announced the fi ndings of glyphosate resistant Kochia in Southern Alberta in early Now that this resistant Kochia has been found, relying on Group 2 plus glyphosate tank-mixes to control these Kochia populations will not work. To be successful you will need to utilize an alternate mode of action with your glyphosate and HEAT or DISTINCT plus Roundup Transorb HC are great choices. Utilizing this tank-mix in your operation will help to control those resistant weeds and set your fi elds up for success. Sean Dilk, Technology Development Manager with Monsanto Canada

6 Learn more about HEAT and DISTINCT herbicides and their advantages in resistance management by visiting agsolutions.ca, contacting your BASF retailer, or calling AgSolutions Customer Care at BASF (2273). Always read and follow label directions. AgSolutions, and DISTINCT are registered trade-marks of BASF Corporation; HEAT and KIXOR are registered trade-marks, and the unique KIXOR X symbol is a trade-mark of BASF SE, all used with permission by BASF Canada Inc. MERGE is a registered trade-mark of BASF Canada Inc. Roundup Transorb is a registered trade-mark of Monsanto Technology LLC BASF Canada Inc

7 HEAT herbicide for pre-seed, pre-emergence, and chemfallow HEAT delivers: Fast, complete control of all broadleaf weeds. Consistent control of weeds up to the 8-leaf stage. Weed resistance management. Weeds controlled Canada fl eabane* Narrow-leaved hawk s beard*** Stinkweed Dandelion** Redroot pigweed Volunteer canola (all types)*^ Timing and rates Pre-seed, pre-emergence, or chemfallow HEAT herbicide + Roundup Transorb HC + MERGE adjuvant 10 g/ac (26 g/ha) (80 ac/jug) or 27g/ac (71 g/ha) (30 ac/jug) + (see label for rates) L/ac (0.5 L/ha) All applications Water 5 10 gal/ac ( L/ha) Flixweed Round-leaf mallow Wild buckwheat Kochia* (to 15 cm) Winter and Spring annual cleavers****^ Wild mustard*^ Lamb s quarters See the Roundup label for a full description of additional weeds controlled. *Includes glyphosate-resistant and Group 2-resistant biotypes. When combined with Roundup Transorb HC: **Rapid control of spring emerged seedlings and rapid top growth control of perennials (<15cm); ***Rapid control of (<8cm) Narrow-leaved hawk s beard; ****Rapid control of (up to 4 whorls) Winter and Spring annual cleavers. ^Flushing suppression at the high rate. Always read and follow label directions. AgSolutions is a registered trade-mark of BASF Corporation; HEAT and KIXOR are registered trade-marks, and the unique KIXOR X symbol is a trade-mark of BASF SE, all used with permission by BASF Canada Inc. MERGE is a registered trade-mark of BASF Canada Inc. Roundup Transorb HC is a registered trade-mark of Monsanto Technology LLC BASF Canada Inc. Crops for pre-seed, pre-emergence applications Cereals Barley Tame Oats Canary seed Wheat (spring, winter, durum) Corn Pulses Chick peas Lentil Field peas Soybean The 80 acre/jug rate should be applied in front of lentils and soybeans Tear here

8 DISTINCT herbicide for chemfallow and post-harvest applications DISTINCT delivers: Broader weed spectrum than Roundup Transorb HC alone, with a higher level of control on larger weeds. An effective part of a weed resistance management plan. Non-Group 2 chemistry with unmatched follow-crop options for maximum rotational fl exibility. Weeds controlled Tank-mixed with Roundup Transorb HC, DISTINCT complements control of all weeds on the Roundup Transorb HC label, plus the following problem weeds: Timing and rates Chemfallow or post-harvest All applications Water DISTINCT herbicide + RoundupTransorb HC + MERGE adjuvant 58 g/ac (143 g/ha) + (see label for rates) L/ac (0.5 L/ha) 5 10 gal/ac ( L/ha) ground application only Dandelion Sow thistle Wild buckwheat Canada thistle Winter annuals Round leaved mallow Kochia* Narrow leaved hawks beard Cleavers Russian thistle Flixweed Volunteer Canola (suppression) * Includes glyphosate-resistant and Group 2-resistant biotypes. Control with fall applications (Sept-Oct), suppression in spring/summer applications (May-Aug). For control of Volunteer RR Canola, add 200 ml/ac of 2,4-D. Follow crops Wheat Soybeans Field peas Oats Flax Chickpea Canary seed Barley Canola Lentils Corn Sunflower Always read and follow label directions. AgSolutions, and DISTINCT are registered trade-marks of BASF Corporation; MERGE is a registered trade-mark of BASF Canada Inc. Roundup Transorb HC is a registered trade-mark of Monsanto Technology LLC BASF Canada Inc. For crops in bold above, DISTINCT must be applied before October 1st to safely rotate into these crops the following year. Tear here