1. Research into the biological control of
Fireweed
Andy Sheppard & Rachel McFadyen
Brian Sindel, Louise Morin, Royce Holtkamp, Kathyn Edmonson & Dept Ag Hawaii
Fireweed Workshop Bega May 08

2. Biocontrol as a part of integrated management Recommendations
Outline
Know your target
Biocontrol history
Biocontrol future?
Biocontrol as a part of integrated management
Recommendations
Fireweed Workshop Bega May 08

3. Know the target: Taxonomy
Fireweed part of a complex of probably 3-6 species in South Africa
Senecio madagascariensis 2N
Kwazulu-Natal
Senecio inaequidens 4N
Lesotho
(Hilliard 1977)
S. burchelli
S. skirrhodon
S. pellucidus
All species hybridise and produce viable seed x
S. harveianus 2N ?
Weed in Australia, South America, Hawaii & Japan
(Lafuma et al. 2003)
Weed in Europe
Fireweed Workshop Bega May 08

4. Phylogeny of Senecio (Pelser et al. 2002)
Australian native group
Fireweed group
Fireweed Workshop Bega May 08

5. Know your target: Origin and Distribution
∆ S. madagascariensis
▲S. harveianus
 S. inequidens
KWZULU-NATAL
Lafuma et al. 2003
Fireweed Workshop Bega May 08

6. Natural enemies on Fireweed in Australia
Survey by Hosking & Holtcamp and in late 1990’s all the common insects attacking S. pinnatifolis group in E Australia also attacked fireweed
further evidence of close taxonomic
Fireweed in Australia systematically attacked by the Australian rust (Puccinia lagenophorae)
also recorded from S. pinnatifolius group.
Fireweed Workshop Bega May 08

7. Know the Target : Variation in Australia
Still spreading - covering only small part of potential distribution (Sindel & Michael 1996, Sindel 2008) and becoming more sympatric with related native species in S. pinnatifolius group.
S. pinnatifolius group spp. also invade pasture systems (e.g. S. brigalowensis in central QLD)
Sterile hybrids with most closely related S. pinnatifolius group
Toxic alkaloids low but variable
Fireweed Workshop Bega May 08

8. Biocontrol as a part of integrated management Recommendations
Outline
Know your target
Biocontrol history
Biocontrol future?
Biocontrol as a part of integrated management
Recommendations
Fireweed Workshop Bega May 08

9. Biocontrol history : Australia
Declared target for biological control in 1991
Surveys for agents in Madagascar prior to fireweed evolutionary origins knowledge led to testing pyralid (Phycitodes sp.) and a tortricid (Lobesia sp.). Both failed to be fireweed specific (McFayden and Sparks 1996)
PPRI scientists in South Africa found a rust fungus on S. madagascariensis.
MLA funded project initiated to assess this fungus in
Dried specimen
Fireweed Workshop Bega May 08

10. Biocontrol history: Search for rust fungi (Morin 2003)
▲ S. madagascariensis populations located without rust fungus
 S. madagascariensis populations located without rust fungus
Morin 2003
Fireweed Workshop Bega May 08

11. Biocontrol history: Assessment of SAf rust in Quarantine (Morin 2003)
Isolates shipped to Quarantine in Canberra
Taxonomic evidence suggested new rust was also P. lagenophorae
could not be confirmed
SAf rust isolates
attacked AU fireweed
failed to penetrate S. lautus subsp. lanceolatus in trials
SAf rust isolates comparable, but sometimes less virulent than Australian P. lagenophorae rust isolates
18 records of P. lagenophorae on S. lautus in Australia suggest at least different pathotypes exist.
Fireweed Workshop Bega May 08

12. Biocontrol history: Overseas activities (Hawaii)
Host specificity testing complete for an Arctiid moth (Secusio extensa) collected from “fireweed” in Madagascar
Development completed on 5 plant genera (Senecio, Emilia, Erechtites, Delairea & Crassocephalum) in the tribe Senecioneae
Not nearly specific enough for release in Australia with many native Senecio’s
Fireweed Workshop Bega May 08

13. Biocontrol history: Overseas activities (Hawaii)
Other potential agents
Nyctemera apicalis (Arctiid tiger moth) appears restricted to tribe Senecioneae
Hawaii planning further agent selection activities in Africa in June-August 2008
Fireweed Workshop Bega May 08

14. Biocontrol as a part of integrated management Recommendations
Outline
Know your target
Biocontrol history
Biocontrol future?
Biocontrol as a part of integrated management
Recommendations
Fireweed Workshop Bega May 08

15. Biocontrol future : For v against
Biocontrol only continent- wide control option
Fireweed still spreading
Existing grazing management options have not provided a widespread solution
Weed is exotic
Biocontrol of other Senecio sp. has been successful in Australia
Weed biocontrol historically good investment B/C 23:1
Weed of international relevance
Against
Fireweed hybridises with native Senecio’s – minimal taxonomic isolation
Mono-specific biocontrol agents hard to find?
No specific/effective agents have yet been found
Even with specific agents 1 in 3 Biocontrol programs fail
Biocontrol will require nearer a $3-5M budget ($300K < 10% required)
Long time frames (next generation benefits)
Fireweed Workshop Bega May 08

16. Biocontrol future : Analysing “Against”
Fireweed hybridises with native Senecio’s – minimal taxonomic isolation
Targets with congeneric natives are the focus of other programs in Australia Senecio’s, Acacia’s, Sporobolus’s, Nasella’s, Rubus’s, Rumex’s etc.
McFadyen IOBC conference paper Feb 2008 – “Classical Biocontrol: possible even for weeds with congeneric native species”
Fireweed Workshop Bega May 08

17. Biocontrol future : Analysing “Against”
Mono-specific biocontrol agents hard to find?
Availability of monospecific agents – not as hard as expected
species specific agents - most widespread targets have a few.
biotype specific arthropods (e.g. Chromolaena)
biotype specific pathogens (pathotypes) the norm for obligate pathogenic fungi used as biocontrol agents
McFadyen IOBC conference paper Feb 2008 – “Classical Biocontrol: possible even for weeds with congeneric native species”
Fireweed Workshop Bega May 08

18. Biocontrol future : Analysing “Against”
No specific/effective agents have yet been found
Past surveys have focussed outside the native range of S. madagascariensis
Surveys in native range focussed on one rust pathogen – although no others were clearly obvious
Additional searching and screening may reveal more virulent rust pathotypes – no guarantee of success
Manipulating target densities in native range might “trap” effective agents not found by observation
Fireweed Workshop Bega May 08

19. Biocontrol future : Analysing “Against”
Even with specific agents 1 in 3 Biocontrol programs fail
Successful programs exist so such agents can be effective (e.g. Senecio jacobaea, Rumex pulcher)
McFadyen IOBC conference paper Feb 2008 – “Classical Biocontrol: possible even for weeds with congeneric native species”
Fireweed Workshop Bega May 08

20. Biocontrol future : Analysing “Against”
Biocontrol will require nearer a $3-5M budget ($300K < 10% required)
Long time frames (next generation benefits)
Generic issues for all biocontrol programs… history has shown they are usually worth the investment
Fireweed Workshop Bega May 08

21. Biocontrol as a part of integrated management Recommendations
Outline
Know your target
Biocontrol history
Biocontrol future?
Biocontrol as a part of integrated management
Recommendations
Fireweed Workshop Bega May 08

22. Biocontrol as a part of IWM
Practitioners consistently argue biocontrol provides a basis for integrated weed management particularly in grazing systems – key focus of CRC Weed Management Systems
Defeating the Weed Menace proposal ($800K) in 2005 included biocontrol as a component of developing a larger IWM package built around the Fireweed Regional Weed Management Plan – not funded.
Project activities in South Africa can also explore the ecology and status of the plant there and the ecological basis for its lower abundance or how it is managed in the native range.
– strategic directions for both agent selection and IWM.
Fireweed Workshop Bega May 08

23. Biocontrol as a part of integrated management Recommendations
Outline
Know your target
Biocontrol history
Biocontrol future?
Biocontrol as a part of integrated management
Recommendations
Fireweed Workshop Bega May 08

24. Recommendations : past and present
Detailed surveys of potential biocontrol agents… should …be carried out in…the country identified as the origin of fireweed (McFadyen & Sparks 1996)
DNA sequencing to [understand] whether or not the SAf rust fungus is P. lagenophorae [and] Additional screening of rust isolates from SAf .. in the hope of finding isolates that are more virulent to those in Australia (no guarantee of success) (Morin 2003).
There is a sound case for further investigation of the potential for biological control of fireweed in Australia (Sindel 2008)
Fireweed Workshop Bega May 08

25. Recommendations : Agent specificity and IWM
If no fireweed-specific agents are found a test case could be initiated for release of an agent known to attack a native plant species or group of species (McFadyen & Sparks 1996).
economic study of the impact of fireweed on grazing [and]
environmental impact study on the impacts of fireweed and any biocontrol agents on native Senecios
For biological control agents that are not absolutely specific to fireweed a cost benefit analysis is required to weigh up the case for release of such organisms (Sindel 2008)
Search for biocontrol based integrated weed management systems to tackle the increasing fireweed problem in eastern Australia (Morin 2002)
Fireweed Workshop Bega May 08

26. Not much has changed
Fireweed Workshop Bega May 08