From Dr. Pennings

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From Dr. Pennings

• This was a nice study looking at the incidence of
  two invasive species in 3 neighborhoods.

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Introduced and Invasive Weeds

• Biodiversity Project Fall 2006

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Introduced and Invasive Weeds

• Cuscuta japonica Giant Asian Dodder
• Native to Asia (China, Korea, Japan)
• first Houston sighting in 2001 near Hobby airport
• Lysianthes asarifolia - South American Gingerleaf
  
• Native to S. America (Bolivia, Argentina,
  Venezuala)
• First Houston sighting approx. 1999 in Hunter
  Creek Village

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Purpose of Study

• Compare prevalence of species within three
  Houston neighborhoods
• Newer Homes constructed in 1970
• Older Homes constructed in 1920
• Adjacent Homes proximity to neighborhood with
  Lysianthes identified by Texas Forest Service
  (Hunter Creek Village)
• Survey includes 685 homes
• www.zillow.com to find area information

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Hypothesis

• A) Cuscuta is effectively controlled in Houston
  by evidence of occurrence
• B) Lysianthes will be more prevalent in specific
  regions
• Older homes will have a higher prevalence of
  gingerleaf than new homes because mature trees
  provide a shady environment. Also, planned
  communities in new neighborhoods will have strict
  deed requirements and more weed control in public
  areas surrounding homes.
• Homes located close to Hunter Creek Village will
  have a higher number of incidents than new homes
  because they have had more exposure to the weed.

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Map of Hunters Creek Village, Piney Point, and
Hedwig Village
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Cuscuta japonica Giant Asian Dodder
Devils vine, Strangleweed, Witchs hair
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• Taxonomy
• Kingdom  Plantae -- Plants
• Subkingdom  Tracheobionta -- Vascular plants
• Superdivision  Spermatophyta -- Seed
  plants
• Division  Magnoliophyta -- Flowering
  plants
• Class  Magnoliopsida -- Dicotyledons
• Subclass  Asteridae
• Order  Solanales
• Family  Cuscutaceae -- Dodder
  family
• Genus  Cuscuta L. -- dodder
• Species  Cuscuta
  japonica Choisy -- Japanese dodder
• Distribution
• Greenhouses in California, South Carolina all
  eradicated
• Texas Forest Service has found four sites of
  Cuscuta within Houston (2002 article date)

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Characteristics

• Highly parasitic, lacks chlorophyll
• Can grow 6 inches per day
• Spreads through haustoria and seed production
• Threatens live oak and crape myrtle
• Seeds can survive for years
• Host species cannot be salvaged
• Soil must be sterilized for effective control
• May have been introduced and grown for medicinal
  properties

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South American Ginger Leaf Lycianthes asarifolia
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• found in Memorial Park

• prefers wet, shady areas
• competitive with St. Augustine Grass
• reproduces vegetatively and sexually
• seeds are slow to germinate

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• Taxonomy
• Kingdom  Plantae -- Plants
• Subkingdom  Tracheobionta -- Vascular plants
• Superdivision  Spermatophyta -- Seed plants
• Division  Magnoliophyta -- Flowering plants
• Class  Magnoliopsida --
  Dicotyledons
• Subclass  Asteridae
• Order  Solanales
• Family  Solanaceae -- Potato
  family
• Genus  Lycianthes (Dunal)
  Hassler -- lycianthes P
• Species  Lycianthes
  asarifolia (Kunth Bouché) Bitter gingerleaf
• Distribution
• Documented in City Park New Orleans, Lousiana
• First reported in Hunter Creek Village in 1999
• Several sweeps of herbicide have been ineffective
• May have spread through seeds or fruit
• Possibly spread through construction and/or lawn
  service companies
• Fruit is edible can be consumed raw, made into
  candy (tablila), or into preserves

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Found only in Harris County
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Lycianthes - New Homes

• Jersey Village neighborhood
• Approx. 200 homes surveyed
• Built within last 30 years
• Located 30 miles from Hunter Creek Village (site
  of first incidence)
• Greatest occurrence of Lycianthes

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Lycianthes Old homes

• Montrose/University of St. Thomas area
• Constructed in 1920
• Approx. 200 homes surveyed
• Less prevalence of Lycianthes
• One incident of Cuscuta

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Cuscuta japonica - 1424 Kipling Dr
?Cuscuta
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Lycianthes Adjacent Homes

• Piney Point Village and Hedwig Village
• Located close to Hunter Creek Village
• Similar to results from New Home data

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Results for Lycianthes

• Old Homes had the fewest occurrence
• New Homes had highest occurrence

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Conclusion

• Hypothesis a) Cuscuta
• Rejected one occurrence of Cuscuta beyond
  Hobby airport
• Hypothesis b) Lycianthes
• Rejected New homes had the highest occurrence,
  followed by adjacent homes and older homes

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Discussion

• Homes in Montrose/Univ. St. Thomas area, while
  having mature trees, also had more landscaping
  and less grass. This reduces possible
  environments for growth of Lycianthes

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• Construction may have led to spread of Lycianthes
  in new neighborhoods.
• Similarity of occurrence between adjacent
  neighborhoods (Hedwig, Piney Point) and new
  neighborhoods (Jersey Village) indicates that
  invasion of Lycianthes may be widespread in
  Houston
• Most homes with Lycianthes had adjacent neighbors
  who were also affected.
• Higher incidence of Lycianthes may result in
  increased herbicide usage, which is damaging to
  the environment.
• While eradication of Cuscuta in known areas has
  been diligent, continual monitoring is crucial

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Even a well-maintained lawn
can have this invasive weed
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References

• USDA plant database http//plants.usda.gov/java/pr
  ofile?symbolLYAS4
• Texas Invasives website http//www.texasinvasives.
  org/Invasives_Database/Results/Detail.asp?SymbolC
  UJA
• TFS article - Lycianthes http//txforestservice.ta
  mu.edu/shared/article.asp?DocumentID370mcurban
• Cuscuta article http//www.invasive.org/eastern/ot
  her/DicCusCjO01.pdf
• Biology Department at Texas AM - Dodder
• http//www-aes.tamu.edu/mary/dodder/dodderMR.ppt
• http//dodder.tamu.edu/dist.asp
• Lycianthes article from Texas AM
• http//www-aes.tamu.edu/mary/Lastuff/La.htm