Biological control of Chinese tallow Triadica sebifera,

Euphorbiaceae

• Greg Wheeler, USDA/ARS/IPRL Ft Lauderdale, FL • S. Steininger, C. Nguyen, K. Dyer, S. Wright, USDA/ARS • Jianqing Ding, Yi Wang, Wei Huang, Jialiang Zhang – Chinese

Academy of Sciences, Wuhan China • Matt Purcell, CSIRO, Australia

Biological control of Chinese tallow

• Overseas surveys • Quarantine host testing • Preparation for field

release of agents

Triadica sebifera (Chinese Tallow, Popcorn Tree, Tallowtree, Florida Aspen)

Tallow distribution in China • Distributed in

China south of the Yellow river to Hong Kong

• Cultivated sp. • Possibly 200 spp

of herbivore pests that are potential biological control agents

Tallow’s distribution US • The dominant woody sp

in many forests & wetlands

• Infestations impact endangered Whooping crane and Attwater’s prairie chicken populations

• Expanding range, $200-$400 million to control over next 20 yrs

• biological control is a sustainable, cost-effective alternative

EDDMapS 2012

Tallow biological control agents

Heterapoderopsis bicallosicollis

Bikasha collaris

Gadirtha fusca

Caloptilia triadicae

Heterapoderopsis bicallosicollis

Bikasha collaris flea beetle

Bikasha collaris

Larval Feeding Adult Feeding

Damaged roots

Bikasha collaris

Results (Larvae) • 68 & 78 non-target species tested by Chinese &

USDA/ARS/IPRL • All larvae quickly died on non-targets, except:

– Hippomane mancinella (manchineel) (3 of 80 larvae ate roots - died)

– Ricinus communis (castorbean) (2 of 50 larva matured to adult - died)

• Choice tests of 10 spp completed with little damage to non-targets

Results (Adults) • 78 non-target species have been tested no-

choice starvation tests – Feeding (nibbling) occurred on three species

• Ditrysinia (=Sebastiania) fruticosa (Gulf Sebastian bush)

• Gymnanthes lucida (Oysterwood) S. Fla sp

• Hippomane mancinella (manchineel) S. Fla sp

• Eggs only produced when adults fed tallow – – no reproduction on other spp

• Choice tests with non-targets indicates < 1% feeding compared with control on H. mancinella,

Euphorbia hypericifolia (sandmat), and Manihot esculenta (cassava)

Bikasha impact

• Larvae 0, 5,10/plt • Adults 0, 5, 10/plt • Both larvae &

adults decrease biomass

• Greatest impact from both larval & adult feeding

Number of larvae | Number of adults

New Insects on Tallow Gadirtha inexacta

larvae •Gadirtha fusca (Nolidae) •Narrow host range from Chinese field surveys and lab tests •Quarantine 2012 and being tested now (Jan 2015) •Larvae safe (38 spp tested) •Very damaging

Leaves fed to one late instar larva

Leaf damage of one larva after 2 days (135 cm2)

New Insects on Tallow - insects being developed

•Unidentified stem galling midge

•Abundant in many areas of China

•Work continues in China

Midge stem gall

The Adventive Biological Control Agent

• Appeared nr Tampa & Gainesville in 2008

• From China (Caloptilia triadicae)

• Heavy damage to Tallow plants

Tallow biological control release study

•Sites in North Florida •Pre-release description of the plant population

•Population recruitment, growth and mortality (~100 plants/site)

•Plant biomass allocation (~30 plants/site)

•Monitor each year & compare impact of biological control pre-release vs post-release

Tallow demographics in North Florida sites

• Factors influence demography (mortality, growth, reproduction)?

• Possible factors: – Water depth and duration of

flooding • data suggests increased mortality and

decreased growth. Reproduction? – Herbivory

• Survival greatest for large trees

• Seedlings had highest mortality

Tallow demographics in North Florida sites

Years2012 2013 2014

Surv

ival

(%)

0

20

40

60

80

100

SeedlingsSaplingsReproductive trees

Could flood influence tree mortality?

Response to flooding • hypertrophy of lenticels • adventitious roots

Caloptilia Impact on tallow • What is the effect of

Caloptilia on tallow demographics?

• Our studies show complete defoliation, suggesting more herbivores needed

Tallow biological control

Priorities 2015: China

•Gall midge rearing & specificity

Florida •Continue:

• flea beetle TAG • moth Gadirtha fusca - TAG •Gall midge specificity

• Pre-release demographics

Gadirtha fusca larvae

Bikasha collaris

Acknowledgements • Funding:

Florida Fish Wildlife Conservation Commission (D. Schmitz, D. Leslie, G. Jubinsky)

National Park Service (T. Pernas) USDA/ARS

• Work: S. Steininger, C. Nguyen, S. Wright, K. Dyer

USDA/ARS Jianqing Ding, Yi Wang, Wei Huang, Jialiang Zhang,

Chinese Academy of Science Purcell, M. CSIRO A. Christman, Paynes Prairie Preserve, DEP M. Cole, G. Nichols, SJRWMD