Weed Identification and Control Jim Wanstall NMDA State Noxious Weed Coordinator
What Is A Weed? A weed is any plant that interferes with the management objectives for a particular site. An invasive weed is a plant that has the ability or tendency to spread and invade a variety of habitat types.
The Term NOXIOUS WEED Is A Legal Term Indicating... A plant species that is not indigenous to New Mexico and that has been targeted pursuant to New Mexico s Noxious Weed Management Act of 1998 for management or control because of its negative impact on the economy or the environment.
New Mexico s Noxious Weed List Class A Weeds: Not currently in NM or limited distribution. Class B Weeds: Limited to a particular area in NM. Class C Weeds: Widespread throughout NM. Watch List: Species of concern, that have the potential to become problematic. More data is needed.
State Noxious Weed List Contains 45 species Updated April 2009
Management and Control. What s The Answer?
What is Your Objective? Obviously You Want to Kill the Weed
Short Term vs Long term Objectives
Short Term vs Long term Objectives
Short Term vs Long Term Considerations Vary with the size and severity of the problem Small patches and individual plants can be as simple as kill the plants It may only require a short term view Larger infestations are much different
Plants out compete other plants for available sites. The system is dynamic, not static.
Long Term Objectives Require an Understanding of Vegetation Dynamics
Succession
Noxious weeds are so aggressive they throw this successional system into disorder. The only component in this model that can shift the plant community in a desirable direction is successional tendency
Noxious weeds are early successional species within an available site. But because of their tenacious character, they can stop succession to a more desirable site plant community.
Moving Succession Along Designed Disturbance = Create available sites Controlled Colonization = Create conditions that favor the plants you want Controlled Performance = Encourage the growth of desired plants
Beginning Plant Community 98% Russian knapweed 2% Cheatgrass Designed Disturbance Broadleaf Herbicide Controlled Colonization Biological Control Controlled Performnce Mowing Cultivation Mowing Fertilization Irrigation Seeding Herbicide Grazing Fertlization Irrigation Burning Grazing Reducing soil Fertitility Non- Selective Herbicide Flooding and Draining Herbicide irrigation Burning Early Spring Grazing Biological Control Ending Plant Community 70% seeded species 20% cheatgrass 10% Russian knapweed
Integrated Pest Management Control Options 1. Cultural planting desirable competitive plants, keeping country in good shape, etc. 2. Mechanical mowing, burning, hoeing, hand pulling, etc. 3. Biological the use of livestock, insects, or pathogens 4. Chemical the use of herbicides
Feral Hogs and Native Plants and Wildlife
Feral Hog Facts Feral Hogs in the US cause more than $1billion in damages and control costs each year Damage due to rooting and wallowing activities Negative impacts on native wildlife such as ground nesting birds New Mexico Populations carry Pseudorabies, Swine Brucellosis, and Hepatitis E Virus Two litters per year with up to 10 per litter
Main Populations in New Mexico Middle Rio Grande N. of Elephant Butte Pecos River Watershed from Texas to DeBaca County Canadian River from Texas to San Miguel County Lincoln National Forest 17 Counties in NM Expanded range from 2 to 17 counties since 2006
Rooting Behavior Creates Available Sites
Available Sites = Opportunity
Identifying Plant Biology The key to successful control
Types of Weed Species Grassy has a fibrous root system Example: Johnson grass Broadleaf any weed that is not a grass. Woody plants can be considered broadleaf. Example: Cocklebur Woody - A. Brush/shrub multi-stem Example: mesquite, scrub oak B. Trees single stem (trunk) Example: salt cedar, elm
Classification of Weeds Based on Their Life Cycle Annual Weeds complete their life cycle in one growing season. The plants come up from seed, grow, flower, produce seed, then die all in one growing season. Means of reproduction: Seed production The KEY To Control: DO NOT ALLOW THE PLANT TO SET SEED!
Annuals Summer annuals: Annuals that germinate in spring and flower in summer to fall. Examples: Puncture vine, Foxtail Winter annuals: Annuals that germinate in the fall/early winter and flower in spring. Examples: Cheatgrass, London rocket
Classification of Weeds Based on Their Life Cycle Biennial Weeds complete their life cycle in two years. These plants come up from seed, produce a rosette the first year, go through the winter (overwinter) as a rosette. During the second growing season, the plant produces a stem, flowers, seed, then dies. The KEY to control: DO NOT ALLOW THE PLANT TO SET SEED!
Scotch, musk and bull thistles
Classification of Weeds Based on Their Life Cycle Perennial Weeds come back year after year from the same vegetative reproductive root systems or stolons (runners). 1. Simple perennial non-branching root system. Example: dandelion 2. Creeping perennial branching root system. Example: field bindweed Management must strive to kill the root system while not allowing the plant to produce seed.
Weed Identification is Important! Management techniques are specific for specific species. Identify both seedlings and mature plants. Note characteristics to consider management techniques. Utilize weed identification books if needed. Weeds of the West, Troublesome Weeds of N.M.
Interactive Weed ID Tool http://weeds.nmsu.edu Simple tool for common weeds of New Mexico and the southwest. Asks a series of questions about plants. Fill in what you know Results will be a list of potential plants with thumbnail pictures of plants.
Noxious Weeds in Southern New Mexico
Russian Knapweed Perennial with widely spreading root system. Emits an allelopathic substance. Toxic to horses. Management plan should include a combination of control methods to stress the plant.
Rounded and papery bracts.
Roots have been observed to grow 6 to 8 feet deep in one season, and a single plant can expand radially up to 14 yards in two seasons
Hoary Cress A perennial. Leaves are clasping Produces by seed and creeping roots. Apply herbicides before flowering.
Hoary Cress-- The problem with treating this plant is that comes out and blooms very early in the spring!
Perennial Pepperweed
Perennial Pepperweed Creeping herbaceous perennial Found mostly in riparian areas, irrigation ditches, floodplains, and wetlands. Perennial roots, root fragments, and seed reproduction New shoots can spread more than 10 feet from the parent plant each year.
Perennial pepperweed Height of up to 6 feet tall. Non-clasping leaves that are lance-shaped. Small, white-petaled flowers in dense, rounded clusters at the end of the branches.
Malta starthistle Winter Annual Stiff, wiry stems, 1 to 3 feet tall. Leaves are green to blue-green, covered with fine hairs. Basal leaves are oval to linear, entire to lobed margins. Stem leaves are narrow, with bases that extend down the stem creating wings. Oval yellow flower heads are single or in groups of 2 to 3 at the ends of stems with stiff purple or brown bracts. 2005 James M. Andre
Yellow vs Malta
African rue Small, bright green succulent perennial herb. Flowers have five white petals and produce a cylindrical 2-4 celled fruit with many seeds. Toxic to cattle, sheep, and horses. Seeds are the most toxic part of the plant. 2001 CDFA
2001 CDFA 2001 CDFA 2001 CDFA
Scotch Musk and Bull thistles
Musk Thistle A biennial. Reproduces only from seed. Produces up to 20,000 seeds per plant. Seeds viable in the soil 8 to 10 years. Will not tolerate tillage. Apply chemical to rosettes in the spring or fall. Key to management success: Prevent seed formation!
Musk Thistle Biological Control
Bull Thistle - Scotch Thistle Both are biennials. Both plants are highly competitive. Can sever roots below ground to kill plants. Chemical control works best at rosette stage. Prevent seed set!
Scotch Thistle
Bi-annual Thistles What Kills Them Mechanical Control Easily outcompeted Chemical Control before plant bolts Aminopyralid (Milestone) 3-5oz/Ac Clopyralid (Transline).67-1.33pts/Ac Dicamba (Banvel,Vanquish,Clarity) 1-2pts/Ac
Dodder (Cuscata spp.)
Over 150 species worldwide Annual Parasitic Plant on broadleaves No leaves or chlorophyll Obtain all of their growth requirements (water, minerals, carbohydrates) by attaching themselves to other living green plants (host plants).
In spring, dodder seeds germinate near the soil surface and send up slender, thread-like twining stems Stem sways or rotates slowly until it touches the stem or leaf of another plant and begins to wind around it. Stem immediately forms small tiny suckerlike roots, which penetrate the stems or leaves of a host plant.
After attaching to a susceptible plant, the lower end of the dodder withers and breaks its connection with the ground Dodder flowers are numerous, tiny whitish to pinkish, and form in small clusters along the stems Each flower forms a small, globular seedpod with 2 to 4 seeds. May be able to survive for 20 years in the soil
Non Herbicidal Methods Planting non-host grass crops, winter crops, trees Active broadleaf weed control Hand-pulling, burning, cutting, or close mowing
. Herbicidal Control Herbicide Alfalfa Clover Tomato Potato Kerb PRE PRE NR b NR Treflan PRE NR PRE c PRE c Prowl PRE NR PRE PRE Roundup POST a NR NR NR Dacthal NR NR POST POST Raptor d POST POST NR NR Pursuit d POST POST NR NR Gramoxone e POST POST NR NR Scythe e POST POST NR NR
Contact Me Jim Wanstall NMDA State Noxious Weed Coordinator P.O Box 464 Tome, N.M. 87060 jwanstall@nmda.nmsu.edu (505)269-7761