WHAT'S NEW WITH BAYER CROPSCIENCE PRODUCTS
the non-negotiables of weed management
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n addition to his Bachelors Degree in Agronomy, Jeff Stachler has both a Masters and PhD in Weed Science, making him one of the most prominent weed specialists in the U.S. As an advocate for practicing solid resistance management strategies, Dr. Stachler has been preaching the dangers of herbicide
resistance in his home country for over a decade and now believes that Canada has the unique opportunity to show the rest of the world how to avoid what he calls the current “U.S. resistance disaster.” “Canada has the chance to show the rest of the world how it has to be done. So
far we’ve failed in the U.S., but Canada can succeed.” Stachler reports. Stachler outlines best agronomic practices in what could be considered his manifesto, Stachler’s Non-Negotiables of Weed Management. In eight easy-to-follow points, he provides the framework for effective weed control and resistance management.
STACHLER’S Non-Negotiables of Weed Management Practice perimeter weed management
• Leave a 1m weed-free zone around all crop edges, including wet spots (i.e. mow down weeds along field boundaries) Practice ZERO tolerance
• Allow NO weed(s) to reproduce (no seed production) • Remove/destroy surviving plants by hand (cheaper and more effective vs. the cost of additional herbicides and applications, and the price of resistance) Scout fields
• Before planting • Before crop emergence • Before 1st post-emergence application • 5-14 days after each post emergence application • Observe response of individual plants • Scout field whenever weeds start to flower Diversify weed management strategies • Cultural practices - Crop rotation - Delay planting in weediest fields - Maximize crop density and minimize the time to canopy closure - Maintain soil health/fertility for your crop • Rotate herbicide sites (modes) of action - As often as possible (at least once every two years) • Rotate herbicide-resistant/tolerant crops - At least once every two years • Where possible, apply soil-applied herbicides to all crops - Allows flexibility for timing post application - Adjust rates for soil types
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FARM FORUM / SPRING 2013
Start clean
• No-tillage – Apply a non-selective herbicide in a pre-burn application or utilize a cover crop • Conventional/reduced tillage – Till early/ deep enough to remove annual weeds, if not, apply non-selective herbicide prior to crop emergence Understand weed biology
• Take advantage of the key vulnerabilities of each species - Target specific problem weeds and resistant species • The impact of leaving one weed behind - 1 year seeding = 7 years weeding • Understand weed seed dispersal/movement - Based on a 25% emergence rate, a 10% chance of inheriting the same resistance mutation and the same MOA used year over year – one wild oat plant produces the following: (Year/Resistant wild oat plants), Y1=1, Y2=5, Y3=125, Y4=625, Y5=Over 3,000 - Means of weed seed dispersal include water, machinery, wind or other carrier (human, animals, birds) Respond quickly to a changing weed
population • When just a few weeds escape a herbicide application, consider that the herbicide program is broken and needs to be fixed to prevent a disaster • Don’t always blame the weather as the main cause of herbicide misses (genetics can account for up to 50% of the problem)
Maximize herbicide activity • Choose the most effective herbicide(s) for the most difficult weeds (know the mode of action/herbicide group numbers and understand how herbicides work) • Combine multiple modes of action that target the same weed whenever possible - Each individual active ingredient within the mix must provide effective control of the target species • Apply post-emergence herbicides to small <3” annual weeds • Use full labelled rates of herbicides - Must follow when using post-emergence herbicides • Include the most effective adjuvant(s) for ALL herbicides - Follow recommended rates for adjuvants as specified on product labels. • Use correct spray volume (follow label directions) • Use correct droplet size - Droplet size can vary between contact herbicides and translocating herbicides, always consult product label for correct droplet size • Use 15” nozzle spacing • Reduce sprayer travel speeds to10km/hr • Apply during the best weather conditions - Warm, humid, and sunny conditions - Avoid spraying in cool conditions (<3°C) - Maximize rain-fastness interval • Time of day (several herbicides are less effective when sprayed after 9:00 PM and until 8:00 AM)