Common tansy prompted direct seeder Wayne Nontell to build a ditch sprayer in his search for solutions to this potentially problematic weed.
Wayne has just 2 years of direct seeding experience but is already seeing common tansy in his fields. He farms south of Tisdale in an area, which certainly has a lot of this weed present in the roadside right-of-ways and uncultivated pieces of land. He says he is already seeing common tansy moving out 50 yards from the road ditches. He was advised by his local Westco Ace that the time to control the weed was now and he is in total agreement. The bulk of the stands of common tansy are still in the ditches. It is certainly obvious that these stands are spreading in untilled areas such as roadside ditches. They are especially obvious at this time of year as the stocks are quite tough and tall and can be seen sticking out of the snow.
The sprayer Wayne built is really a conversion of an older model field sprayer. He cut the right hand boom down to about 20¢ and suspended it about 5¢ off the ground. It is hinged so it can swing out to the side in spraying position or back to trail behind the sprayer in transport position. Wayne has made the sprayer more versatile by allowing the spray solution to be directed to a length of hose with a handgun attached. For spraying fence lines the solution can also be directed to a section of vertical boom on the other side of the sprayer.
When spraying roadside ditches, it is imperative to realize that someone owns this land. In most instances this will be the rural municipality. Permission must be obtained before spraying on their property. Contact with the 2 RM's that Wayne farms in indicates that they recognize the problems that are developing and will be quite receptive to producers making an effort to find solutions. One of the issues to keep in mind is that these are not agricultural lands and the regulations are therefore different. One of the regulations is that you have to have an industrial pesticide applicator's license to spray roadside ditches. Note that this is different than the agricultural pesticide applicator's license needed to do custom spraying on agricultural cropland. It would also be wise to know your liability requirements for this type of herbicide application.
As a licensed applicator, for liability reasons, you are going to want to adhere to regulations and registrations. There are 2 herbicides that have common tansy on their label. These products are industrial herbicides. Industrial herbicides tend to be the kind of products that are used for roadside, highway and industrial right-of-way spraying.
One of these products is Telar. Its' active ingredient is chlorosulfuron which used to be formulated under the trade name Glean for agricultural production. At 28 g/ac, the rate that gives common tansy control, the cost will be $36/ac. The most effective application time is when growth is about 4² high. According to a company rep this is the time when the plants are the most actively growing and you will get the most product distributed in the plant. He also says that you will get the best coverage at this stage. One of the detrimental effects of this rate of Telar will be on grass species. Smooth bromegrass, which is very common in our ditches, will be set back and yellowing will be evident although well-established plants will survive. A company rep also suggests that this product will cause needle die back and leaf drop if trees get sprayed. Healthy large trees will probably be injured but will survive. Smaller, stressed trees may not survive exposure to Telar. At the rate that you need to kill common tansy there is going to be a lot of residual and you are going to have to be careful to stay away from the rooting areas of trees. The label also says to be cautious applying Telar to areas where the herbicide may be washed to non-target areas.
The other product registered to control common tansy is Escort. Its active ingredient is metsulfuron methyl, which is the active ingredient in Ally. Again a company rep says the best time to apply it is when growth is at the 4² stage. The registration states that biennials and perennials can be treated up to early bud stage. The Escort rate for common tansy is 8g/ac and will cost $12/ac. Ron Standish, out of Calgary with True North Specialty Products, a company that sells industrial herbicides, indicates that Escort will be very active on Common Tansy. He suggests that the 12g/ac rate is better but it is very important to use the recommended surfactant. It also is a product with some residual and will likely have the same effect on trees as Telar. It will also set back grass species but probably not as severely as Telar. If a heavy rainfall occurs shortly after applying Escort the product will be moved into the rooting zone and the grass will be more severely affected.
Except for areas like Wayne has, where the common tansy is heavy enough to be "everywhere" in the ditches, it is probably a wise use of resources to spot spray stands. A comment from Midland Vegetation, a company hired by the Dept of Highways to spray their right-of-ways, was that common tansy was most often observed in difficult-to-spray locations as far as a ditch-spraying rig was concerned. Garry Bowes, a researcher with the Integrated Noxious Weed Management Program, who works mainly with scentless chamomile, also says that he sees common tansy in fence lines and hard-to-control places where it's best to use a hand sprayer. Garry points out that producers need to be very conscious of picking up tansy seed on the edge of their fields and putting it through harvesting equipment and thus carrying on the spreading process. For scentless chamomile, and possibly common tansy, he promotes spraying 6¢ into the ditch edge so that there is less chance of picking up seed and spreading it during harvesting. One of the cautions for blanket application of herbicides in ditches is the potential destruction of a diversity of species that may flourish in ditches. Although we don't know all of the benefits of bio-diversity it seems that even for large-scale agriculture like we have in Saskatchewan, the advantages of maintaining as much bio-diversity as possible may pay off.
There are a lot of things we don't know about common tansy. It would certainly be to our advantage to have some research time put into this weed given the odds that it may spread and become a threat like scentless chamomile.
Fortunately there are some herbicides available to combat common tansy. It looks like a serious enough threat that direct seeders who see it on the edge of their land, need to schedule time into their weed control program to combat it before a seed bank builds up in their fields.