Controlo Biológico em Portugal: Proposta do INVADER-B em Bruxelas

December 18th | Brussels

Use of Trichilogaster acaciaelongifoliae for biological control of the invasive plant Acacia longifolia – a safe and cost-effective method

Hélia Marchante(1,2), Elizabete Marchante(1) & Helena Freitas(1)

technical-scientific consultation of John Hoffmann(3)

(1) Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Portugal(2)Department of Environment, Agrarian School, Polytechnic Institute of Coimbra, Portugal(3)University of Cape Town, South Africa


The problem (1)

Invasion by Acacia longifolia

- Exotic tree, from Australia

- Introduced in the early 20th century for sand stabilisation

- At present: invades extensive areas of coastal dunes and other habitats in Portugal and other MS: Spain, France, Italy




The problem (1)


- Exotic tree, from Australia

- Introduced in the early 20th century for sand stabilisation

- At present: invades extensive areas of coastal dunes and other habitats in Portugal and other MS: Spain, France, Italy

- Key point: massive seed production – large long-lived seed bank fast re-invasion potential







The problem (2)


- Major Impacts:

- Decreases biodiversity; threatens protected species & habitats, e.g., Natura 2000 sites and Nature Reserves






The problem (2)


- Major Impacts:


- Changes soil biology and chemistry;

- Decreases forest productivity



The problem (2)


- Major Impacts:




- Increases fire hazard



The problem (2)


- Major Impacts:




- Increases fire hazard

Economic impacts: >> 1M€ + non-available data



• prohibitively expensive • fails to succeed due to copious seed banks

mechanical and chemical control available

The solution?





• prohibitively expensive

Biological control

Sustainable alternatives needed!

• fails to succeed due to copious seed banks

mechanical and chemical control available

The solution?


• Based on scientifically sound principles and protocols• Cost effective, sustainable & environmentally benign• Key tool for Invasive Alien Species management worldwide (CBD;

EPPO; European Strategy Invasive Alien Species)• Good safety record

Worldwide (for plants)• Since late 1800s, > 400 agents against ca. 150 target plants/

weeds• Many target weeds significantly or permanently controlled

Can biological control be the solution?



Can biological control be the solution?Europe:• Over 300 releases of 176 predators/ parasitoids against insects;

e.g., Anaphes inexpectatus against Gonipterus platensis (Eucalyptus globulus) in Portugal

• Only 1 agent against an invasive plant – released in 2010 in the UK: Aphalara itadori to control Fallopia japonica

http://news.bbc.co.uk/2/hi/8555378.stm http://www.guardian.co.uk/environment/2009/jul/23/japanese-knotweed-bug-control


and Trichilogaster acaciaelongifoliae?

1mm


• Australian bud-galling wasp (Hymenoptera: Pteromalidae), 3mm

Trichilogaster acaciaelongifoliae

1mm



• Mono-specific – affects exclusively A. longifolia

• Annual life cycle:

• 362 days inside galls;

• Emergence of , search for flower (vegetative) buds; ♀

• oviposition and death after 2-3 days





• Mono-specific – affects exclusively A. longifolia

• Annual life cycle:

• 362 days inside galls;

• Emergence of , search for flower (vegetative) buds; ♀

• oviposition and death after 2-3 days

• galls develop instead of flowers – NO SEEDS produced




Short term effects:

• seed production & dispersal decline;




Short term effects:

• seed production & dispersal decline;

• no addition to the seed bank

Long term effects:

• reduction of germination post-control, fire or other disturbances

• physiological stress - plants die as cannot cope with heavy gall

loads


Host-specificity tests• Conducted from September to December 2005 – 2010• Female wasps obtained from galls (South Africa)• Specificity test

• 40 non-target species tested (different criteria)• Flower & vegetative buds dissected to detect eggs

1 - Non-choice test2 - Paired-choice test3 - Trials on potted plants 4 - Field surveys in South Africa and Australia


Host-specificity tests

Results:• Oviposition in ONLY 3 non-target species in non-choice tests (Acacia melanoxylon, Vitis vinifera, Cytisus striatis) BUT confinement in cages disrupts normal behavior

Trials on potted plants: • Galls ONLY developed on A. longifolia (able to complete the life

cycle)

Field surveys in South Africa and Australia: • Galls ONLY detected on A. longifolia


South Africa: detailed long-term studies• Released in 1982• Non-target species were not affected except for negligible galls in

Acacia melanoxylon and Paraserianthes lophanta (invasives)• Significantly reduced seed production (> 85%) and curtails

vegetative growth and area invaded• 1980: A. longifolia top 10 Invasive plants 2013: trivial

Specificity tests in Portugal (additional list of species) • NO GALLS in any non-target species

YES, T. acaciaelongifoliae can be safely used decreases economic and biological impacts of A. longifolia in a

cost-effective, sustainable way, without undesirable effects

Is it safe?


Future?Ideal conditions to follow up (INVADER-B project - ongoing)• Assess/ follow the distribution of A. longifolia and biocontrol

agent (remote sensing); • Monitoring plan in place to measure T. acaciaelongifoliae

establishment and success;

TO STRESS:• Imported into quarantine facilities; only females that emerge

will be released

Doing nothing is the biggest risk! More species lost, more money spent, more difficult the solution…


Thank you!

Investor Relations

Controlo Biológico em Portugal: Proposta do INVADER-B em Bruxelas