South Dakota State University Extension encourages landowners to keep an eye out for leafy spurge. The noxious weed has been spotted in areas of north-central South Dakota that have not traditionally had problems with it in the past.
"Since these new patches are developing landowners need to scout their pastures, hay lands, ditches and shelterbelts for this aggressive noxious weed," said Mark Rosenberg, SDSU Extension agronomy and weeds field specialist.
The South Dakota Department of Agriculture reports that leafy spurge infests 309,420 acres of land in the state. Noxious weeds are non-native plant species that are a concern to land owners and managers. They replace and impede agriculture, recreation and wildlife.
Leafy spurge 101
Leafy spurge is difficult to control weed that is considered noxious throughout South Dakota; below are some quick facts.
Life cycle: A creeping perennial.
Leaves: Alternate, long, narrow, drooping, dark green.
Stems: 2 to 3 feet tall. Plant contains milky sap.
Flowers: Small green flowers surrounded by yellow-green bracts. Seed explodes from a three-celled capsule.
Roots: Dark brown with pink buds. They may reach 20 feet deep.
To manage leafy spurge because it is a perennial species that develops extensive root systems, Rosenberg, said, it is very difficult to control. "Management programs typically require several years and can be very costly. Therefore, it is strongly recommended to watch for new patches and control infestations while they are small," he said.
Standard herbicide programs include; Tordon (spot treatment rate 1-2 qt.), Tordon (1.5pt.)+2,4-D ester (1 lb. AE), or Plateau (8-12 oz.) All rates are per acre.
Rosenberg said that herbicides should be applied early in June at flowering or to wait until regrowth in the fall (September-October or while the white sap is still flowing). He added that although Plateau may be used around some tree species, as always landowners need to read and follow label precautions.
Perspective (4.75- 8 oz.) is also labeled for control. However Rosenberg said it cannot be applied to grass that will be grazed or hayed.
For large infestations or sensitive areas, Rosenberg encouraged landowners to consider introducing bio-control agents such as leafy spurge flea beetles (Aphthona lacertosa or Aphthona nigriscutis).