CARRINGTON, N.D. - Saline areas have grown at an astounding rate in this region over the past several years - and so has kocia, which thrives in saline soils. Saline areas are generally not profitable for raising crops so are many times left unattended during the growing season. The problem with that, according to Mike Ostlie, an agronomist at the Carrington Research Extension Center, is kochia thrives in saline soils and many times have free reign in saline spots.
"They are able to grow as they want and produce as many seeds as they are able to in these areas," Ostlie said. "Kochia is drought, salts and heat tolerant, so there are not many environmental factors that are going to take care of this problem on its own.
"Managing these areas is going to be very important for protecting the rest of your productive land," he added.
The case of glyphosate resistant kochia has expanded the last couple years, almost as fast as the saline seep problem. In 2011 there were two locations in North Dakota where resistant populations of kochia were confirmed, Ostlie told a group of farmers and crop consultants at a recent Herbicide Resistance workshop. However, in 2012 the majority of the counties in a band extending from Towner County on the north edge to Dickey County on the south are now infected with resistant kochia, according to Ostlie.
With this background, Ostlie went on to define the "Kochia Konundrum (conundrum)" for controlling this weed in saline areas. Many times growers will resort to tillage to control resistant kochia, but tillage will actually bring more salts to the surface and will disturb the natural flow of trying to get the salts to move lower in the soil profile by leaching, thus making the problem even worse. This presents a conundrum for controlling kochia in saline areas.
In tackling this problem, Ostlie referred to an old saying "the best thing to do is the right thing; the next best thing you can do is the wrong thing; and the worst thing you can do is nothing." That, he said, certainly applies to herbicide resistance.
He then listed some guidelines for helping with the kochia problem in saline areas. The first three are ways of helping control the salt problem while the remainder are methods that can be employed to help reduce the impact of kochia.
*Manage the salts. Try to eliminate the salt problem, because if you are working to eliminate the salt you probably will be providing competition in these areas to the kochia. This ultimately means you will end up with less kochia and that will limit weed seed production. "Anything you can do to eliminate weed seed production potential will help you long term," he said.
*Increase organic matter. This can be accomplished by adding manure to the area, since it will be hard to increase organic matter just from the crop residue, since hardly anything will grow in these areas.
*Find ways to lower the water table. This can be accomplished with tile drainage or by planting salt-tolerant crops in the area to remove soil moisture. Crops such as energy beets, salt tolerant alfalfa, barley and sunflower do have a moderate degree of resistance to salty soils and will remove soil moisture during their growth. "Any kind of production you can get on these areas will help bring them back into production sooner," he said.
*Use a residual herbicide product. A product such as Banvel, at higher rates, will remain as a residue in the soil and provide some control of later emerging kochia.
*Size is everything. Since there is very little translocation of the herbicide in kochia, it is important to spray when the plant is less than four inches tall.
*Tillage. Tillage can work quite well, Ostlie noted, but there are the concerns mentioned above when using tillage in saline areas.
*Mowing. If mowing practices are used, care must be taken to mow very close to the ground. Otherwise, Ostlie noted, the mowing will promote auxiliary branches which will continue to grow and produce seed.
*What not to do. The same thing over and over again. "If something isn't working in regards to weed control, change what you are doing," Ostlie recommended. In 2012 glyphosate-resistant kochia showed up in many areas where it wasn't suspected, he noted. And just because you didn't have a problem in 2012 doesn't mean you aren't going to have a problem in 2013. Based on the 2012 expansion of the problem, glyphosate-resistant kochia could be the fastest growing resistance issue we have seen yet, which Ostlie termed very troubling.
"Any field, even if it wasn't treated with glyphosate last year, could have glyphosate-resistant kochia," he said.
He closed by saying there are rumors of a glyphosate resistance field kit that will allow a grower to go out in their field and sample leaves from plants. Two or three days later a color test will show whether a plant is resistant or not resistant to glyphosate.