Why glyphosate alone is not enough

…to control key weeds.

Pre-seed application offers real advantages, but glyphosate alone does not provide full control of some winter and spring emerging annuals. “Cleavers, dandelion, narrow-leaved hawk’s beard and flixweed are all weeds to control early,” explains Brian Wintonyk, agronomist with Dow AgroSciences. “In areas where spring moisture levels are high, they will regrow quickly as the soil warms up, so controlling these prior to seeding is very important.”

…for tough winter annuals.

Winter annuals like narrow-leaved hawk’s beard, cleavers, chickweed and stinkweed emerge in late fall and overwinter as rosettes or 3- to 4-leaved seedlings. Come spring, they set seed and flourish ahead of crops, outcompeting for moisture and nutrients.

…for weeds that flush.

Flushing weeds like wild buckwheat, cleavers, dandelion, scentless chamomile, shepherd’s purse and stinkweed outcompete crops for valuable nutrients and moisture, spring and fall. Glyphosate alone controls only those weeds actively growing at the time of application, leaving flushing weeds to keep coming back.

…for volunteer canola.

Glyphosate alone will not control Roundup® Ready volunteer canola – a growing problem. “This will continue to be an emerging issue due to the 10 million acres of Roundup Ready canola grown annually in western Canada,” Wintonyk says. “Glyphosate alone onlys control emerged InVigor® and Clearfield® canola volunteers.”

All types of volunteer canola:
• Decrease yields by outcompeting crops for nutrients.
• Decrease grain quality with increased dockage.
• Can act as a host for blackleg and increase flea beetle pressure (because the seed is untreated).
• Can act as a host for clubroot and, if not controlled, help it spread.

…to manage glyphosate resistance.

Glyphosate resistance is a growing concern due to its frequent and repeated use. Glyphosate contains just one active ingredient and works through one mode of action. Effective herbicide resistance management requires the use of products with multiple modes of action that deliver overlapping activity on the same weeds.

Suspect herbicide resistance when:
• Weeds escape in odd shaped patches.
• Some labeled weeds are controlled while others are not.
• Records show repeat use of the same herbicide or herbicide group.
• Escapes aren’t attributable to environmental conditions or emergence after application.
• The same herbicide or group fails in the same area of a field the previous year.

“Growers are better off getting superior control with one application of PrePass™ XC than hoping for the best with an application of glyphosate alone or, worse, with multiple glyphosate applications,” Wintonyk says.

As a multi-mode of action product, PrePass XC is an effective resistance management tool that can help slow the development of glyphosate resistant weed populations.

…for weeds that have not yet emerged.

Glyphosate alone only controls weeds that are actively growing at the time of application. “Many weeds germinate or regrow afterward, resulting in early weed competition for the emerging crop,” says Wintonyk.

To control weeds that have not yet emerged, PrePass XC delivers 21-days SoilActive™ technology, controlling both actively growing weeds and those that emerge following application. It allows growers to spray earlier and trust the technology to control weeds until their crop is in the ground. Susceptible weeds include: volunteer canola, wild buckwheat, flixweed, cleavers, stinkweed, chickweed and more.

“Growers can easily spray PrePass two weeks ahead of seeding. As susceptible weeds emerge in treated fields, they take up the active ingredient through the root system and it stops plant growth,” Wintonyk says.

…to support early seeding.

Research suggests yields increase with early seeding*. Seeding early, in mid to late April or early May, allows the crop to make good use of available moisture, get a head start on weeds, and flower earlier, resulting in less heat stress. Early-seeded cereals produce higher grain quality and increased yields when seeded into clean fields. To produce top yields, early weed control is essential.

“PrePass™ XC allows growers to seed early into a clean field that will stay clean while the crop is established,” says Wintonyk. “With PrePass providing 21 days of SoilActive control, growers can focus on getting their seed into the ground as early as possible.”

*According to Manitoba Agriculture, Food and Rural Development (MAFRD)