Friday, July 25, 2008

Musk Thistle – Favorable rains last fall have created the right conditions for lots of thistles this spring.

The rosette stage of growth is ideal for controlling musk thistle plants this spring. That means you should apply herbicides soon, while the plants are in the rosette stage, prior to bolting.

Several herbicides are effective and recommended for musk thistle control. One of the most effective is Tordon 22K®, but be careful with Tordon since it can also kill woody plants, including trees and shrubs. A new herbicide called Milestone® also does an excellent job of controlling musk thistle. Both Milestone and Tordon will help control other weeds that usually appear later in the season.

2,4-D also works very well, but you will get better thistle control by using a combination of 2,4-D and dicamba (Banvel). Other herbicides labeled for controlling musk thistles in pastures include; Redeem®, Grazon®, Cimarron®, Ally® and Curtail®. Always be sure to read and follow label instructions, and treat at the proper time.

All these herbicides will work for you this spring if you spray before musk thistles bolt and send up flowering stalks. After flowering, the shovel is about the only method remaining to control thistles this year.

Eastern Redcedar Trees – continue to explode in many area pastures. These trees reduce forage production, make animal handling difficult, and encourage pastures to shift from warm-season to cool-season grasses.

           Cedar can be controlled with herbicides, by cutting, or fire. By far the least expensive, when it can be used safely, is fire. The effectiveness of fire declines, however, as trees get large. Herbicides like Tordon 22K® and Velpar® applied directly to the soil beneath the tree work very well, but they’re time consuming to apply and more expensive. While cutting can be cheaper, it is even more time consuming, especially if cut trees need to be removed.

Recent research in Nebraska has shown that a combination of control measures can combine the strengths of each method while overcoming most disadvantages.

For best results, a prescribed fire is needed to kill many smaller trees and to weaken or improve accessibility to larger trees. It also can be used periodically, maybe every four to eight years, to eliminate new infestations.

After the prescribed burn, it usually is best to wait a year before using herbicides or cutting to complete the job because some trees that appear to survive the fire will eventually die.

For more information on cedar control, contact your local extension office or visit the UNL Extension Publications Web site at http://extension.unl.edu/publications.