Seed & Chemical
By Donna Fleury
DuPont has developed a herbicide technology that provides growers and agronomists with more flexibility for customized weed control. Dupont PrecisionPac herbicides can be customized to target specific weeds present in a field with a specific herbicide blend. This technology is based on a numbering system similar to how fertilizer products are numbered.
“In 2011, PrecisionPac herbicides were made available in three main categories, each blend identified by specific numbers,” explains Kirk Dammann, Product Manager PrecisionPac Herbicides in Weyburn, Saskatchewan. “The numbers represent the key active ingredients they contain, which is much like the way fertilizer blends are numbered.” The numbers are preceded by three designations describing their primary usage. A total of 12 PrecisionPac herbicides are now registered for use.
The three categories are: NC for non-crop or out of crop, PP for post-emergent products in the black, grey-wooded and brown soil zones and DB is a dicamba blend suited for the brown and dark brown soil zones. The letters designate the herbicide category, while the numbers indicate which active ingredients make up each blend. Retailer locations that have the new delivery system can blend up to six different herbicide active ingredients in various ratios. (See chart. NOTE: The actual names of the PrecisionPac products, as registered with the PMRA, don’t have dashes between the numbers, but dashes are included here for clarity in this article.)
“The numbering system is used instead of names because each blend is a customized offering targeting certain weed spectrums,” says Dammann. “Using a post-emergent numbering example, PP 25-25 is a post-emergent product blend of equal amounts of thifensulfuron and tribenuron active ingredients. Another example, PP 23-23-5 is a similar post-emergent blend with a percentage of the active ingredient metsulfuron included. The blends can be customized to provide anywhere from extended weed control to non-residual control.”
For growers and agronomists, the key is field scouting and identifying the target weeds for a particular field. Then the retailer can develop a blend to match that weed spectrum. “The customized blend is dispensed directly into a grower bag, with sizes ranging from 20 acres to 320 acres or matched to a sprayer tank size,” says Dammann. “Therefore, growers are applying the exact amount of product they need for a particular field, with no left over product to manage. The grower bags make for easier handling because it replaces several cases of product.”
One of the biggest benefits is the ease of handling and mixing because there is no measuring and no confusion. “For example, if you are working with a custom applicator, the grower bag comes with a sticker that identifies the field and acres to be treated with that bag, with the exact amount to put into the sprayer,” adds Dammann. “The final product is simple and easy to use, even if the numbering system doesn’t seem that simple at first.”
Dammann notes that another benefit to the system is the ability to quickly react to new weed problems, such as night flowering catchfly or white cockle. Retailers can blend the actives to address specific weeds problems in a timely manner. Along with support from agronomists and retailers, DuPont has also developed an online PrecisionPac Solution Finder to help growers identify the PrecisionPac herbicides best suited to their individual farm and weed spectrum.
“Crop and herbicide rotations are important and we’ve developed the system based on sound management practices,” explains Dammann. “For products that include the active metsulfuron for extended control, growers will need to pay attention to any cropping restrictions. However, none of the other blends are a concern. The system also has options to blend multiple herbicide groups, along with the many Group 2 product actives available.” The Group 2 actives can be paired with Group 4 products such as Perimeter Mega PrecisionPac herbicide or MCPA or 2,4-D to help with herbicide rotation and resistance management.
“I think this is a pretty innovative approach to help growers and is a great option over only cased goods,” says Dammann. “The system is easy to use and applicable to both smaller and larger acreage growers in western Canada for a wide range of crops. For 2012 there will be 124 retailer locations in western Canada with the dispensing technology for multiple actives. The delivery systems are placed with leading retailers that want to drive value and differentiate themselves and to offer customized solutions for their clients.
Herbicide management: Know your active ingredients and modes of action
Identifying the active ingredients and their mode of action in herbicide products will help growers know if they have the right combination to address their weed spectrum and for managing weed resistance. “We are working with growers to help them learn to recognize the active ingredients in the herbicides they use,” explains Ken Sapsford, Research Assistant with the Department of Plant Sciences at the University of Saskatchewan. “As new products come on the market, such as numbered products like PrecisionPac herbicides, growers are able to determine the percentage of active ingredients in the blend.”
Understanding the active ingredients and modes of action is particularly important for managing herbicide resistance.
There is research data showing that a mixture of modes of action in the same year is better than just a straight rotation of modes of action for managing herbicide resistance. Identifying which mode of action is in each product blend helps growers know if they need to add something else to control their weed spectrum.
“For example, if growers have a Group 2 resistant kochia or cleavers problem, then they can’t use a Group 2 product alone. They should use a combination product of a Group 2 with a Group 4, such as dicamba or fluroxypyr like Perimeter Mega PrecisionPac, to control resistant weeds,” says Sapsford. “Another advantage of putting a dicamba or fluroxypry Group 4 product with a Group 2 is the combination controls some of the tougher to control broadleaf weeds with two modes of action.” Even if you don’t have resistant weed biotypes in your field right now, using two modes of action will help prevent developing resistance while managing tough to control weeds like cleavers, wild buckwheat and others.
“Records should be kept for each active ingredient and each product applied to individual fields throughout the entire year to ensure the right products and combinations are being applied,” says Sapsford. “This is very important when applying certain active ingredients.” For example, metsulfuron should not be applied more than once per year on a field. Therefore, if a product such as Express Pro is used for a preseed burnoff, then incrop products such as PP 23-23-5 can’t be used in the same year because they both contain metsulfuron, and could result in recropping restrictions.
“The best management strategy is to know your weeds, select the right active ingredients and modes of action in products or product blends and follow label directions,” says Sapsford. With the right information, growers can select the best product and combinations to meet their herbicide management and resistance prevention strategies.