You are hereThe Landscape Alerts

The Landscape Alerts

LAWN BURWEED - IT’S A STICKY PROBLEM

Original Source: 
Tim R. Murphy, UGA Extension Weed Scientist (Retired)
 
February 2012
 
The warming of spring days brings about a flurry of spring sports activities such as soccer, softball, baseball, and spring training for football. The players are eager to demonstrate their athletic abilities, the coaches are ready to mold their championship team but, all of a sudden, players begin to complain about the field. “There’s some little weed out there that has stickers on it”. The coaches quickly huddle around the “sticky problem” and observe that the field is infested with a spiny, low growing weed that is annoying the players. The question becomes “What is this weed and how the #!*@ do we get rid of it?”
 
The weed in question is most commonly lawn burweed (Soliva pterosperma), a.k.a. spurweed, stickerweed, sandbur, sanbur and sandspur. Lawn burweed is a winter annual member of the Aster family. The weed germinates in the early fall months as temperatures cool and remains small or inconspicuous during the cold winter months. However, as temperatures warm in the early spring, or about the same time as spring sports activities, lawn burweed initiates a period of rapid growth and begins to form spine-tipped burs in the leaf axils. The sharp-tipped spiny burs of this weed can cause minor irritation to the skin.
 
Key identification characteristics of lawn burweed are:
1) Opposite, sparsely hairy leaves that are divided into numerous segments or lobes
2) Small, inconspicuous flowers
3) Spine tipped burs that are found in the leaf axils (junction of leaf and stem)
 
Lawn burweed attains an overall diameter of up to 6 inches and a height of about 3 to 4 inches. It is commonly found in the Coastal Plain and Piedmont regions of Georgia.
 
Lawn burweed can be easily controlled during the winter months of December, January and February. The weed can also be effectively controlled in March in most areas of Georgia. Atrazine (Aatrex is a Restricted Use Herbicide), simazine (Princep, Wynstar, others) and Sencor Turf will effectively control lawn burweed. Carefully read the label to make certain the herbicide you select can be used on your turf-type. This group of herbicides should not be used on bermudagrass fields overseeded with a cool-season turfgrass or on tall fescue fields since they can injure cool-season turfgrasses. Atrazine also should only be used on dormant Bermuda grass since it can damage green Bermuda. Atrazine can damage other turfgrasses when used at higher temperatures so – read and follow all label directions!
 
Other options to control lawn burweed are 2,4-D, dicamba and two-way and three-way mixtures of 2,4-D, 2,4-DP, MCPP and dicamba. Dicamba and the two-way and tree-way mixtures generally provide better lawn burweed control than 2,4-D. These products can be used on tall fescue fields, fall overseeded bermudagrass fields in which the overseeded cool-season grass has been mowed four to five times and non-overseeded bermudagrass fields. This group of products should be applied on a warm (air temperatures at least 55 degrees F.), sunny day. Two to three weeks after the initial application, lawn burweed control should be evaluated. If control is not acceptable, an additional application may be necessary.
 
The key factor to effectively controlling lawn burweed is to apply an appropriate herbicide during the winter months. Lawn burweed is small and easier to control at this time of the year than in April and May. Also, turfgrasses are not actively-growing during the winter months and have better tolerance to some herbicides.
 
Lawn burweed can be controlled in late-March, April and early May. However, two main facts should be considered. Lawn burweed begins to die as late spring temperatures approach 90 o F and the plant is harder to control once the spiny burs or stickers have formed. Multiple herbicide applications are usually necessary, which increases the risk of temporary injury to the turfgrass. Additionally, it takes time for the herbicide to control lawn burweed, and after death, it takes time for the dead lawn burweed plants to decompose. Therein lies one of the main problems with late treatments. Dead lawn burweed plants contain dead, or brown spine-tipped burs. Dead or alive, the spiny burs still present a problem. The only recourse at this point is to allow time for the plant to naturally decompose.
 
For pesticide recommendations see the UGA Pest Management Handbook – www.ent.uga.edu/pmh/
 
For further information contact your local County Extension Office – (800) ASK-UGA1
 
Please share this information with others in the landscape & turf industry.
 
Image credit - Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Tags

Virginia Buttonweed Identification and Control in Turfgrass

Original Source: 
Patrick McCullough and Jialin Yu, UGA Department of Crop and Soil Sciences
This is an exerpt from a longer publication. See the rest of the publication here - http://tinyurl.com/c4r293h
 
Virginia buttonweed (Diodia virginiana L.) is a troublesome broadleaf weed in turfgrass throughout the southeastern United States. Virginia buttonweed is a deep-rooted perennial with prostrate or spreading branches. It usually proliferates in moist to wet areas and can tolerate mowing heights as low as one-half inch. The species is a member of the Rubiaceae family and is found from New Jersey, west to Missouri and south into the Gulf Coast states.
 
Virginia buttonweed leaves are slightly thickened, opposite without petioles and slightly rough along the margins (Picture 1). Leaves are green on the upper surface, light green on the lower surface and often have a mottled yellow mosaic appearance caused by a virus that commonly infects foliage. Branched stems are occasionally hairy and reproduction occurs via seeds, roots or stem fragments. (see pictures in publication online) Flowers are white with four star-shaped petals, which sometimes have pink streaks in the center and two sepals. Fruit are green, elliptically shaped, hairy and ridged.
 
Tags

Search Content