Volume 37, Number 18 | December 5, 2011
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PRACTICAL PRODUCTION TIPS FOR THE PRAIRIE FARMER
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A plan of attack for cleavers Cleavers infestations can lower yields and result in a quality downgrade, especially in canola. Best control is achieved through early control with the right product and ample water volume BY MEGAN OLEKSYN
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h a t ’s n o x i o u s , competitive and sticks to your shirt? Cleavers. Cleavers are aggressive broadleaf climbing weeds that can have a big impact on the bottom line. These highly competitive annuals are especially bad news when it comes to canola. Agronomists estimate that a heavy infestation of cleavers (100 plants per square metre) can cut canola yields by 20 per cent. That’s a major financial loss in a year where we’re looking at canola prices around $12 a bushel, but that’s not the end of the story. “Because its seed is similar both in shape and size to a canola seed, cleavers is termed as an ‘inseparable’ weed seed,” says Dave Dubuc, grain marketing coach with Providence Grain Solutions at Fort Saskatchewan, Alta. “Contamination of canola by anything over one per cent by weight of cleavers can result in a downgrade from No. 1 to No. 2, and you can even see cleavers bring your grade right down to sample.” And since one individual cleavers plant can produce 3,500 seeds, and herbicide resistance in cleavers has recently been reported in Alberta, Western Canada is potentially looking at a lot of downgraded canola if this awful weed isn’t controlled early and often.
THE LIMITS OF GLYPHOSATE “When Roundup Ready canola came to market, we saw a decrease in cleavers in canola samples,” says Dubuc. “And really, we don’t see a lot of this significant downgrading happening anymore.” But glyphosate is not a silver bullet for cleavers, according to Clark Brenzil, provincial weed control specialist with the Saskatchewan Ministry of Agriculture. “With the popularity and effi-
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cacy of glyphosate, we are seeing that growers have become overconfident in their expectations from glyphosate, because they have always seen positive results. Now, more and more growers go in too late, reduce their water volumes and still expect miracles.” The Canada Seeds Act lists cleavers as a Class 2 primary noxious weed, which has a significant meaning to pedigreed seed growers — control is mandatory for them. Hugh J. Beckie with Agriculture and Agri-Food Canada at the Saskatoon Research Centre developed a model that projects the first weeds to develop resistance to glyphosate in Canada. The model ranks cleavers third in the Parkland region (black or grey soils). Glyphosate, however, is not farmers’ biggest worry when it comes to cleavers and herbicide resistance. Since 1996, there have been many recorded cases of Group 2 (ALS inhibitors) resistance across the Prairies. Brenzil notes that in recent Alberta surveys, 40 per cent of cleavers were found to be resistant to Group 2s, which poses a significant dilemma for farmers — particularly those growing peas. Currently, the University of Saskatchewan is looking at alternative chemistries to control cleavers in non-cereal products, but early management is still the key to cleavers control in all crops.
TIPS FOR CONTROL “Scout, and scout early,” says Leighton Blashko, market development specialist with Bayer CropScience. “Controlling or suppressing cleavers in the early stages is the only way to manage them. They are known for their ability to germinate throughout the growing season, so growers must get in early but then manage the ones that come up later as well.” Early control really does mean early — the best control is achieved when the weed is really nothing more than a tiny seedling.
PHOTO: LYNDSEY SMITH
Adult cleavers’ leaves whorl around a square stem. The white flowers produce pairs of seeds covered in hooked hairs. The leaves, stems and seeds will all attach to clothing or animals aiding in the weed’s spread. Adult cleavers are easily identified as their leaves are arranged in a whorl pattern around a square stem. Once in the adult stage, cleavers produce numerous tiny white flowers, which then produce pairs of seeds covered in hooked hairs. Not only
are the leaves sticky, but the seeds are too, attaching themselves to clothing, animals and anything else within reach. This ability helps to spread seeds far and wide. “It is very important to control cleavers before they go to seed,”
In This Issue
says Gregory Sekulic, Canola Council agronomist in the Peace Region. “Young cleavers under three whorls are far easier to control than the ones that look like Christmas trees.”
» CONTINUED ON PAGE 4
Wheat & Chaff ..................
2
Features ............................
5
Crop Advisor’s Casebook ..
8
Columns ........................... 20 Machinery & Shop ............ 26 Cattleman’s Corner .......... 33
Soybeans a fit on lentil and canola acres
Three must-have gifts for farmers
BOBBIE BRATRUD PAGE 14
RON SETTLER PAGE 29
FarmLife ............................ 40