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Enue E. Sicairos RuelasOctober 6th 2005
University of ArizonaSWES
A quiet enemy: Salvinia molesta
October 6th 2005 A quiet enemy: Salvinia molesta 2
Overview
• Salvinia molesta (Giant Salvinia, Kariba weed, African pyle) is a free floating fern native to southeastern Brazil.
• Dense mats affect the growth of native vegetation, wildlife and degrade water quality.
• Over the past 70 years, S. molesta has spread to tropical and subtropical regions
The Nature Conservancy, 2000
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 3
Taxonomic classification
Salvinia molesta belongs to a monogeneric family
Salviniaceae
S. auriculata
S. herzogii
S. biloba
S. molesta
S. auriculata complex
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 4
Morphology and reproduction
Weed management ,2003
Hairy floating leaves
Root like submerged leaf
• Great morphological variation depending on the conditions of habitat
• Vegetative Reproduction
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 5
Geographical distribution
Native from Southeastern
Brazil
Sri Lanka
Australia
India
Philippines
South America
Cuba Malaysia
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 6
Presence in the United States
1990 - S. molestawas introduced asan ornamentalplant
1995 - Outside of cultivation in private pond in South Carolina
1998 - New outbreaks were registered in Texas
1999 - Invaded over 50 localities in southern tier states
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 7
Presence in Mexico
ag.arizona.edu/OALS/ ALN/aln44/milich11.html
Entered for first time in 2003 through the
Colorado river
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 8
Ecological impacts
Detrimental
• Salvinia mats depress oxygen concentrations.
• Mats blocks the access to drinking water by humans, domestic stock and wild life.
• Clog irrigation and drainage canals.
• Prevents water use for recreational activities, such as swimming, boating, water skiing, and fishing
USGS,2005
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 9
Ecological impacts
Beneficial
• S. Molesta has been used as a compost and mulch
• As a supplement to food for livestock in some Asian countries
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 10
Management options
A) Chemical control
– 1940’s emulsifiable oils containing pentachlorophenol was used in Sri Lanka.
– Paraquat and sodium arsenite have been used to but only provide short term control.
B) Physical control
– Manual removal has been successful in controlling S. molesta in the initial, uncrowded stage of population development.
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 11
Management options
C) Biological control Use of the weevil Cyrtobagous salviniae Biology• Adults typically reside on or beneath the fronds
• Eggs are laid individually in cavities formed by thefemale’s feeding activity
Damage
• Adults will feed on the fronds, leaving small irregularly shaped holes
• The plants initially turn brown in small patches until entire mat appears brown and begins to sink Weevil Cyrtobagous salviniae
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 12
Conclusion
• Invasive alien plant and animal species increasingly
threaten biodiversity and bring economic losses
• Maybe, one day, we will learn how to respect Mother
Nature, but in the mean time, we have to find a way to
bring equilibrium again
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 13
Questions?
Overview
Distribution
Impact
Control
Conclusion
Questions
October 6th 2005 A quiet enemy: Salvinia molesta 14
Overview
Distribution
Impact
Control
Conclusion
Questions
Yummy!
