Author: jvogel

Noxious and Invasive Weed Update

Plant Protection and Weed Control

Spring 2021

New and Improved Noxious Weed Regulations

Special points of interest:

Thanks to the Noxious Weed Advisory Committee, a whole lot of people in the Kansas Department of Agriculture, and input from the general public, we now have a revised set of noxious weed regulations. Because of language in the new 2018 Noxious Weed Act, we had to make some changes to the regulations and, since we were working on them anyway, we decided to review all of them and update most of them.
The biggest changes to the regulations are the new noxious weed list, which was removed from the law; the revised control programs for each noxious weed species; and the updated cost share list. are covered in detail in the following articles. These changes are all explained in detail in the following articles.
Other changes that were made involve the delivery of legal notices to the landowner by the county weed directors, the hiring of county weed directors, the content and layout of reports submitted by county weed directors, and a list of required contents of the legal notices, which was moved from the law.
Now, with the updated law and regulations, which went into effect on March 19th, we feel we are ready to move forward into a new era of noxious weed control in Kansas.
If you would like, you can view both the law and the regulations at our website at www.agriculture.ks.gov/noxiousweeds.

Noxious Weed List; The Same Only Different

Inside this issue:

New and Improved Noxious Weed Regulations	1
Noxious Weed List; The Same only Different	1
Updated Noxious Weed Species Control Programs	2
Control Corner: Revised Cost Share Chemicals List	2
Invasive Species Spotlight:Black and European Swallowworts	3

Sign up to receive the
Noxious and Invasive Weed Update automatically via email at agriculture.ks.gov

When the Noxious Weed Act was passed in 2018, it included language which would eliminate the noxious weed list. Therefore, it was imperative that we develop a new list and include it in the revised noxious weed regulations. This is where the title of this article comes in. While it is technically a different list, it has the same species on it as the old one.
The big difference with the new list is that we have broken it up into prioritized sections, or tiers. This will allow us to concentrate different levels and types of control on different weeds, which will, hopefully, allow us to eliminate those weeds we can, and manage the others to keep them from spreading.
The new Category A weeds are those that are either found in small, isolated populations that have the potential of being eradicated from the state or that are not currently known to occur here. Because of this, we will take active and aggressive measures against them to prevent them from becoming established or until they no longer grow in Kansas. These weeds are: Hoary cress, Leafy spurge, Quackgrass, Pignut, Kudzu and Russian knapweed,
The Category B weeds are found throughout the state but in discrete populations. We hope to reduce the size of these established populations while still working to prevent or eradicate new populations. Right now, there is only one species in this category, and it is Canada thistle.
Category C species are well established throughout the state. We will still try to eliminate any new populations while established populations will be managed by any approved control method in an effort to keep them from spreading. These weeds are: Field bindweed, Musk thistle, Sericea lespedeza, Johnsongrass and Bur ragweed.

Page #

Updated Noxious Weed Species Control Programs

Another portion of the regulations that was updated were the Control Programs for each weed. If you read through the regulations, you will only find a quick reference to the control programs because these are considered to be “regulations by reference”. That just means that the actual document is not in the regulations themselves but is merely referred to.
You can find the control programs on our website at www.agriculture.ks.gov/noxiousweeds under the heading “Controlling Noxious Weeds. They outline the official methods of control established by the Secretary of Agriculture as is required by law. These methods include the use of as many of the integrated weed management (IWM) techniques as are possible for each weed. These methods include Biological, Chemical, Cultural and Mechanical controls.
The biological controls involve the use of insects to feed on all or parts of the plant. These insects were only allowed to be introduced from the part of the world where the plant originally came from after extensive studies over several years to make sure they will only feed on the target weed.
Chemical controls, of course, involve the use of herbicides to treat the weeds and are discussed in the next article.
Cultural controls largely include those techniques that prevent the weeds from becoming established in the first place, but also include the use of grazing by livestock.
Mechanical controls are those that include pulling, mowing, cultivation, burning, and other similar methods that physically remove the weed.
One new caveat to the control programs is that, if you are using any of the non-chemical controls for perennial noxious weeds, you must use more than one of those methods at the same time. While it is always a good idea to use as many of the IWM techniques as possible, with perennial weeds and their ability to regrow from their roots, it is especially important to take a multiple-pronged approach when using techniques that do not kill those roots.

Control Corner: Revised Cost Share Chemicals List

The Approved Herbicides for Cost Share list, which is also a regulation by reference, was also revised in these new regulations. This list outlines the different herbicides that are available for cost share from your county noxious weed department. In this new version, it also lists the noxious weeds that are best controlled by each herbicide, and the herbicide’s mode of action (MOA). The mode of action is how an herbicide attacks and kills the target weed. The names of the MOAs are rather technical, so we just list the numerical code. Switching between different MOAs as often as possible helps to prevent a weed from becoming resistant to any herbicides, making them easier to control.
In developing this new list, the Noxious Weed Advisory Committee decided to remove two herbicides, Bromacil and Trifluralin, and added one new herbicide, Florpyrauxifen-benzyl. This was to keep the list as up to date as possible with the latest technologies as possible.
Another change to this list is that it does not show combinations of herbicides. This was to make as many combinations available as possible. In other words, you may combine, as a tank mix or a pre-mix, any two or more herbicides listed for your target weed as you like, as long as they are approved by your county Weed Director and are allowed in accordance with the appropriate labels.
Keep in mind that your county noxious weed department does not need to carry all of the available cost share herbicides, they only need to carry one herbicide for each noxious weed in your county. Also, you can use an herbicide that is not on the cost share list, you will just not be able to buy it from your county noxious weed department or at a cost share price.
The discount provided by the county is established in the noxious weed law which allows for counties with a noxious weed tax levy of 1.5 mils or more to sell cost share herbicides at 75–100% of their cost and counties with a tax levy of less than 1.5 mills to sell cost share herbicides at 50–75% of their cost.
As always, the herbicides available for cost share are for noxious weed use only. If you want to use them for non-noxious weeds, contact your local pesticide dealer.

Plant Protection and Weed Control

Any questions comments or article suggestions, please contact:
Scott S. Marsh
State Weeds Specialist
1320 Research Park Drive
Manhattan, KS 66502
Phone: (785) 564-6697
Fax: (785) 564-6779
E-mail: scott.marsh@kda.ks.gov

Visit our website at:
agriculture.ks.gov

Plant Protection and Weed Control staff work to ensure the health of the state’s native and cultivated plants by excluding or controlling destructive pests, diseases and weeds. Staff examine and analyze pest conditions in crop fields, rangelands, greenhouses and nurseries. Action taken to control potential infestations of new pests, whether they are insects, plants diseases or weeds, is beneficial to the economy and the environment.
Our mission is to:
Exclude or control harmful insects, plant diseases, and weeds;
Ensure Kansas plants and plant products entering commerce are free from quarantined pests;
Provide customers with inspection and certification services.

Invasive Species Spotlight
Black and European Swallow-worts (Cynanchum spp.)

In addition to the two vines on the noxious weed list, field bindweed and kudzu, there are also several invasive vines. One of those is the black swallow-wort (Cynanchum louiseae) which is only found in a few counties in east-central Kansas. Another name for this plant is dog-strangling vine, because of its rapid growth and its tendency to grow up and around trees, “strangling” them.
This, and several other, closely related swallow-worts, are members of the milkweed family. They have similar looking oval, pointed leaves and they also produce seed pods. The swallow-wort pods are more narrow than most milkweed pods and look more like large bean pods. The flowers are also different in that they are dark purple and grow in loose clusters wherever the leaves sprout from the vine.
Like most milkweeds, black swallow-wort’s leaves and roots are toxic to mammals, including livestock. Unlike milkweeds, they are also toxic to monarch butterfly larvae, or caterpillars. Studies have shown that, while it is not common, monarch butterflies will lay their eggs on swallow-wort leaves, possibly mistaking them for a preferred species, honey-vine milkweed. Most, if not all, of the caterpillars that emerge and feed on the swallow-wort leaves will die. This is probably due to the fact that swallow-worts are native to southwestern Europe and did not evolve with the butterfly as our native milkweeds did.