combining different control tactics to reduce hydrilla...
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Combining Different Control Tactics to Reduce Hydrilla Biomass
James Cuda, Jennifer Gillett-Kaufman, William Overholt, Karen Stratman, Raymond Hix, Eutychus Kariuki, Judy Shearer, Emma Weeks,
Joan Bradshaw, Ken Gioeli, Verena-Ulrike Lietze, Elroy Timmer
University of Florida, Florida A&M University, COE-ERDC, Citrus & St. Lucie Co. Extension, Aquatic Vegetation Control
USDA NIFA RAMP Grant 2010-02825
2014 Aquatic Weed Control Shortcourse, Coral Springs, FL, 5-8 May 2014
Outline
• Background on hydrilla
• Options for hydrilla management
• Overview of Hydrilla IPM RAMP
• Introducing the new IPM model
• Current status of research
• Summary and resources
USDA NIFA RAMP Grant 2010-02825
Outline
• Background on hydrilla
USDA NIFA RAMP Grant 2010-02825
Hydrilla, Hydrilla verticillata
• Leaves – small (max. 4/5 inch long, 1/6 inch wide), lanceolate, in whorls of 3-8
• Midrib – distinct and can bear small spines
• Submersed, rooted aquatic plant, propagates tubers, turions, fragments
• Monoecious or dioecious forms
• Stems – long and slender with some branching
Worldwide Distribution of Hydrilla
http://www.discoverlife.org/mp/20m?kind=Hydrilla+verticillata&guide=Aquatic_Invasives
• Introduced in the 1950s
• Occurs in Florida, along southern and eastern coasts, and in California
Hydrilla Distribution
(U.S.A.)
• Continues to spread (top map = records 2002, bottom map = records 2011)
cpDNA haplotypes
China F
China G
China H
Japan
Indonesia
Taiwan
12
19
1 China E 6
5
3
4
2
7
10 19
China A
China C
Korea,
NE U.S.A
Australia,
New Zealand
11
1
11
1
China B,
India
China J China I
Poland
China D
Florida, Texas,
California, Louisiana,
Africa, India,
Panama, Pakistan
22
11
Hydrilla Genetic Studies
Williams et al., unpubl.
Why is hydrilla such a problem? • Non-native plant, introduced without its natural
enemies, outcompetes native vegetation
• Forms dense vegetation mats
• Resistance development to certain herbicides
Withlacoochee River, FL, 1997 Lake Tohopekaliga, FL, 2008
Hydrilla’s Impact on Wildlife
Algae-Harboring Hydrilla Causing Bald Eagle Deaths in
the Southeast
http://animal.discovery.com/guides/wild-birds/a-c/american-coot.html
http://ihunt.com/game/waterfowl/ring-necked-duck
Who Cares? We Do!
USDA NIFA RAMP Grant 2010-02825
Lakefront Homeowners
Elected Officials
Residents
Boaters & Airboaters
Anglers
Duck Hunters
Local Businesses
Federal Government State and
County Agencies
Aquatic Plant Managers
Outline
• Background on hydrilla
• Options for hydrilla management
USDA NIFA RAMP Grant 2010-02825
What are the Options for Hydrilla Management?
• Physical control (drawdowns, barriers)
USDA NIFA RAMP Grant 2010-02825
• Mechanical removal (harvesting)
• Chemical control (herbicides)
• Biological control (herbivores, pathogens)
Chemical Control - Advantages
• Applicable for both small and large areas
• Relatively fast action
• Useful for initial removal of large amounts of biomass
• Selectivity possible through proper choice and rate
• Newer products have good toxicology profiles
• Compatible with other control methods
USDA NIFA RAMP Grant 2010-02825
• Researched since the 1970s
• Foreign exploration in Asia, Africa, and Australia
• Four insect species approved for release – only one established persistent populations with some impact
• Sterile grass carp – successful in closed systems
Bagous
hydrillae
Bagous affinis Asian grass carp
Importation BioControl
Hydrellia balciunasi
Hydrellia pakistanae
Insect images copyright USDA-ARS
• One insect species (native range unknown)
- 1957: First record in the U.S. (Louisiana)
- 1976: First record in Florida (SW, specific location unknown)
- 1992: Detected in Crystal River, Florida
• A fungal pathogen discovered in 1970s; isolated from several U.S. hydrilla populations in 1990s
Augmentative BioControl
Cricotopus lebetis
Mycoleptodiscus terrestris
Hydrilla Miner
• Tip- mining midge
- Larvae feed on living plant tissue
- Rare occurrence
• Prevents “topping out”
• Naturalized in Florida
- No swarms
- Low dispersal distance
- Easily mass reared
Female
Larva
Hydrilla Miner Life Cycle
Female
Larva
Pupa
Egg mass
Cuda et al. (1999, 2002)
Male
Larva and Associated Tip Damage
Credit: D. Denson, RCID
Block 1: Control Block 1: Midge
Cuda et al. (2011)
Lake Rowell, Bradford Co., FL September 2010
Outline
• Background on hydrilla
• Options for hydrilla management
• Overview of Hydrilla IPM RAMP
USDA NIFA RAMP Grant 2010-02825
Hydrilla IPM RAMP • Hydrilla Integrated Pest Management (IPM) Risk
Avoidance and Mitigation Project (RAMP)
• USDA-funded
• Collaboration between research and extension experts
• Innovative methods for managing hydrilla in Florida freshwater bodies
USDA NIFA RAMP Grant 2010-02825
Hydrilla IPM RAMP Objectives
• Evaluate compatibility of new hydrilla control technologies
– Insect, pathogen, herbicide
• Demonstrate a novel integrated strategy for controlling hydrilla
USDA NIFA RAMP Grant 2010-02825
Hydrilla IPM RAMP Collaborators
USDA NIFA RAMP Grant 2010-02825
http://entomology.ifas.ufl.edu/hydrilla
Educational Materials & More
• Campaigns with local newspapers & television stations
• Signs for boat ramps are being developed
Why IPM? Potential benefits
• Increased efficacy
• Decreased herbicide use rates & contact times
• Long term control
• Reduced reliance on herbicides alone
• Resistance management
USDA NIFA RAMP Grant 2010-02825
Integrating BioControls & Herbicides
Messersmith and Adkins. 1995. Weed Technol. 9:199-208.
Outline
• Background on hydrilla
• Options for hydrilla management
• Overview of Hydrilla IPM RAMP
• Introducing the new IPM model
USDA NIFA RAMP Grant 2010-02825
Players in the New Hydrilla IPM Model
Target weed: Hydrilla verticillata (hydrilla) Herbivorous
insect: Cricotopus lebetis
(hydrilla tip miner)
Plant-pathogenic fungus: Mycoleptodiscus terrestris (Mt)
New chemical herbicide: imazamox
(inhibits acetolactate synthase, ALS)
Expected Interactions
• Imazamox branching
• Larvae develop within plant tissue (mining)
• New shoot tips breeding sites for hydrilla tip miner
• Damage kills growing tips & increases susceptibility to infection by Mt
Integrating BioControl Agents with Herbicides
• Must confirm that herbicide does NOT negatively impact biocontrol agents – Directly- Causes mortality – Indirectly- Herbicide reduces plant density (= food
source) below critical level
• Consider applying herbicides to maximize impact of biocontrol agents (tip miner & Mt) – Location – Timing
Outline
• Background on hydrilla
• Options for hydrilla management
• Overview of Hydrilla IPM RAMP
• Introducing the new IPM model
• Current status of research
USDA NIFA RAMP Grant 2010-02825
Compatibility Studies
Replicated Tank Tests Conducted in Lewisville, TX & Vicksburg, MS
• Miner/Mt- Jan to Feb 2013
• Miner/Imazamox- Apr to Jun 2013
USDA NIFA RAMP Grant 2010-02825
Compatibility Tests
•Mt and Tip Miner
USDA NIFA RAMP Grant 2010-02825
Courtesy of L. Nelson & J. Shearer, US ACE ERDC
Tank Test Methods
• Untreated Controls
• Low & High Treatments
– Imazamox (Herbicide)
– Mt (Pathogen)
– Tip Miner (Insect)
Tank Test Results
Compatibility Tests
• Tip Miner and Imazamox
USDA NIFA RAMP Grant 2010-02825
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
Mid
ge A
du
lts
Midge Larvae
Midge Larvae + Imazamox
+
Tank Tests- Compatibility
Tip Miner and Imazamox (30 DAT)
0
100
200
300
400
500
Control Tip miner Imazamox Tip miner +Imazamox
Nu
mb
er
of
hyd
rilla
sh
oo
t ti
ps
Treatment
a a a b
Compatibility Tests
•Mechanical Control and Tip Miner
USDA NIFA RAMP Grant 2010-02825
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
USDA NIFA RAMP Grant 2010-02825
Tank Tests- Compatibility
Outline
• Background on hydrilla
• Options for hydrilla management
• Overview of Hydrilla IPM RAMP
• Introducing the new IPM model
• Current status of research
• Summary and resources
USDA NIFA RAMP Grant 2010-02825
• Research
- Laboratory compatibility studies completed
• Mt and tip miner (2013)
• Tip miner and imazamox (2013)
Mesocosm tests
• Tip miner and mechanical control (2014)
• Extension and Outreach
- Field demonstration sites (2014)
USDA NIFA RAMP Grant 2010-02825
Summary
-
Management Goals
• Integrate Different Control Tactics = IPM
• Eliminate Adverse Effects of Surface Mats
• Reduce Reliance on Herbicides
• Create More Favorable Habitat
Hydrilla IPM RAMP Expected Impacts
• Demonstrate compatibility of different low-risk control tactics
• IPM=> safe, sustainable & cost-effective control of both susceptible and fluridone-resistant hydrilla
• Develop Hydrilla IPM Guide for Florida & other states with hydrilla problems
USDA NIFA RAMP Grant 2010-02825
Resources
• Hydrilla IPM Risk Avoidance and Mitigation Project, http://entomology.ifas.ufl.edu/hydrilla
• Osceola County Hydrilla and Hygrophila Demonstration Project (link available)
• UF/IFAS Center for Aquatic and Invasive Plants (link available)
• Featured Creatures of the UF/IFAS Entomology and Nematology Department (link available)
• Cooperative Extension System (eXtension)
USDA NIFA RAMP Grant 2010-02825
Food for Thought*
• “Are we as a weed science discipline choosing to ignore true integrated solutions to the herbicide resistance problem?”
• “More research on herbicide alternatives is required.”
• “Combinations of a diversity of tactics in [ IPM ] systems augment herbicide-based weed control . . . and lengthen the useful life of valuable herbicide tools.”
*Harker et al. 2012. Our view. Editorial, Weed Sci. 60: 143.
Thanx!
USDA NIFA RAMP Grant 2010-02825