Water Hyacinth

Lori Moshman Department of Entomology, LSU AgCenter

ASWM Invasive Species Webinar November 30, 2017

Agriculture Victoria

Overview

• Water hyacinth biology and identification • History and spread • Current impacts • Effective control methods • Biological control • Case studies • Future outlook and recommendations

ELAW

Water hyacinth (Eichornia crassipes)

NCSU TurfCenter L.J. Mehrhoff

J.H. Kirkbride, GoBotany

Water hyacinth may be confused with natives

Center et al. 2002. In Van Driesche, R., et al., 2002. Biological Control of Invasive Plants in the Eastern United States

Frogbit, Limnobium spongia

S.L. Winterton

Pickerelweed, Pontederia cordata

K. Yatskievych

Heteranthera reniformis

Identification

Look for: • Bulbous base • Fleshy stems • Dark roots • Leaf shape

• Mat-forming • History of known infestation

P. Chadwick/DK Images

Landcare SJ

Water hyacinth has high phenotypic plasticity

Brisbane City Council IUCN/Geoffrey Howard

Source: UNEP/DEWA 2013

1884

Current U.S. distribution

Source: EDDMapS 2017

AsiaNews

DRBC

Ecological and environmental impacts

Management strategies

• Mechanical • Chemical • Biological

G. Lovell/Outdoor Alabama

Management strategies: Mechanical

Pros: • Immediate gratification

Cons: • Hard to dispose of material • Increases plant fragmentation • Heavy use of labor and fuel • Can’t keep up with growth rate • Can’t reach areas with limited

access

May be appropriate for small infestations

Management strategies: Chemical

Pros: • Immediate gratification • Easier than mechanical removal

Cons: • Negative environmental effects • Can’t reach areas with limited

access • Expensive

California State Parks

Appropriate where immediate results are needed or as an integrated approach

Management strategies: Biological Pros: • Works passively • Host-specific • Suppresses plant vigor

Cons: • Control can take years • Monitoring and re-releases

required • Success limited in temperate

climates Katherine Parys

Appropriate for large and recurrent infestations

Biological control agents in the U.S.

G. Strickland

Neochetina eichorniae Neochetina bruchi

S. Marcus

Niphograpta albiguttalis Megamelus scutellaris

Waterhyacinth weevils (Neochetina spp.)

• First released in Florida in 1972

• N. bruchi prefer older leaves and N. eichhorniae prefer younger leaves

• Feeding activity is complementary: better with both species present

• Control possible in 3-5 years

Coetzee et al. 2009. In Muniappan, R., et al., 2009. Biological Control of Tropical Weeds using Arthropods.

Waterhyacinth moth (Niphograpta albiguttalis)

• First released in Florida in 1976

• Established throughout gulf coast states

• Feeding does not directly kill plants, but slows growth and encourages secondary pathogens

• Larvae prefer smaller, bulbous plants

Coetzee et al. 2009. In Muniappan, R., et al., 2009. Biological Control of Tropical Weeds using Arthropods.

Waterhyacinth planthopper (Megamelus scutellaris)

• First released in Florida in 2010

• Nymphs and adults feed on all leaf surfaces

• Winged and wingless forms exist

• Impact on infestations is still being studied

UF/IFAS Featured Creatures http://entnemdept.ufl.edu/creatures/beneficial/bugs/Megamelus_scutellaris.htm

P. Tipping

P. Tipping

Case study: LSU Crest Lake, Baton Rouge

S. Moshman

Case study: LSU Crest Lake, Baton Rouge

Case study: LSU Crest Lake, Baton Rouge

Outcome: • Several mechanical and chemical

control efforts were made to reduce the spread of water hyacinth in the lake

• Regular monitoring and early action are the best ways to prevent excessive growth

Control programs are best tailored to fit specific needs

Factors to consider: • Prevention and early action • Climate/ecoregion • Severity of the infestation • Available personnel • Land use restrictions

Despite invasiveness, water hyacinth is still valued…

Aquatic plant product trade

Aquaria, ponds, koi gardens

…and continues to spread

John Pontier NYSDEQ walmart.com

Water hyacinth is part of a complex of invasive floating aquatic plants

Water lettuce, Pistia stratiotes Giant salvinia, Salvinia molesta Water hyacinth, Eichornia crassipes

Future outlook

• Integrated strategies may be needed for long-term control

• Climate change will affect the rate of spread and efficacy of control

• Monitoring is essential; early spring action is most effective

• Mass rearing operations can help fill the need for biocontrol agents