CANADIAN THISTLE

Management

                                  

My choices of treatment to eradicate Canada Thistle ... #1. 1st Spring  1.5 qt per acre 2,4-D Amine Between June 1 and July 10th.  ( the 1st application) 1st follow up  Fall (Aug 21st) 1 qt. Amine and 1 pint Tordon 2nd follow up following  Spring (June10th and later) 1.5 qts per acre Amine Check in the fall for any stragglers and then again use 1.5 qt Amine. ( I'll bet you don't find any) If there are no more patches in the area to reinfest, your problem will most likely be gone. No more thistles, no more time and expense. #2 If for some reason you cannot spray in the spring, then replace the first spray option with mowing.  But mow before seed production.Three weeks later or as soon as you have 4-6 inches of new lush growth, Use 1 pt per acre Duracor. Before this chemical came along I used 1 qt per acre of Tordon if its in a location I can use tordon. Check your land every year for new seedlings and hit them with 1pt per acre Duracor. Where do the Canadian thistles get restarted at after you have cleaned up an infection. In the low ground where water stands. Ducks and geese and other water birds must carry the seeds. In the wet years you will find new growth around the edges.Stop them there. Waterways should be checked also.. Note after 25 years in this business it is of my opinion that spring spraying for Canadian thistle is good for stopping seed production and weakening the plant for a fall kill. But it is the fall spraying that gets down into the roots. Best kill time is last week in August to 1st of Oct. 1st frost it diminishes. 20 years ago research changed and 1st frost is no longer the time to wait for. Research has show best kill period is before Sept 15th.  A slow spring or fall kill chemical, not a burn down. You do not want to wreck the plumbing system that goes to the roots. Not all plants seed at the same time. Some late growers seed in late August early Sept. Plants mowed or spring sprayed will go to seed by late August, depending on rainfall. If you wait too long after they seed, you have a re-infestation.; SPRAYING ALFALFA If it is roundup ready and a grass mixture you cannot use Roundup. I use Maestro a generic Buctril at the rate of 1 pint per acre. It does not kill the thistle plant. It might look a little sick, it may still produce a seed head, but the seed is sterile. Check with your county extension service for their circular and other recommended chemicals and rates. Always read and follow label requirements.