1 / 20

Andrew McConnachie* & Lorraine Strathie

The Epiblema “Dilemma” : Challenges for its use as a biological control agent for parthenium in Africa. Andrew McConnachie* & Lorraine Strathie (ARC-PPRI, Cedara , South Africa) *mcconnachiea@arc.agric.za. Parthenium hysterophorus.

dillan
Download Presentation

Andrew McConnachie* & Lorraine Strathie

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Epiblema“Dilemma”:Challenges for its use as a biological control agent for parthenium in Africa Andrew McConnachie* & Lorraine Strathie (ARC-PPRI, Cedara, South Africa) *mcconnachiea@arc.agric.za

  2. Parthenium hysterophorus • Weed of international significance – introduced to 30 countries throughout the world (Shabbir 2012)

  3. Parthenium hysterophorus • Current global control strategies: • Chemical • Mechanical • Other (containment, competitive species, etc.) • Biological • Strategies in SA: • Chemical • Biological Pucciniaxanthiivar. parthenii-hysterophorae (Summer rust) Pucciniaabruptavar. partheniicola (Winter rust) Epiblemastrenuana Listronotussetosipennis Carmenta sp. nr ithacae Zygogrammabicolorata Smicronyxlutulentus

  4. Epiblemastrenuana(Tortricidae) • Origin: Widely distributed over North & Central America (Canada in north to Mexico in the south; California in west to eastern seaboard of the USA) • Mode of action: Stem-galler (stems & growing points) • Impact: Significant - plant height and flowering (Dhileepan 2003) • Most damaging and widespread agent in Australia at present

  5. Epiblemastrenuana • Field host range (native range): • Canada: Xanthium commune • USA: P. hysterophorus, X. trifida, X. artemisiifolia, X. psilostachya • Mexico & Caribbean: P.hysterophorus • Laboratory host range: • Mexico: P. hysterophorus, P. confertum, Ambrosia psilostachya, Rudbeckia sp., Bidenspilosa • Australia: P. hysterophorus, Ambrosia artemisifolia, X.strumarium • India: P. hysterophorus, Guizotiaabyssinica

  6. Guizotiaabyssinica(noog, niger seed, blackseed)

  7. The “dilemma” • Epiblema is very damaging & widespread in Australia • Epiblema will rapidly disperse northwards in Africa based on Australian evidence • Guizotianot an issue for SA, but of important consideration for Ethiopia • SA legally obliged to only inform SADC members of releases • Polyphagousin native range • Future pressure from SA roleplayers to further test and consider Epiblema

  8. Epiblemastrenuana • Field host range (native range): • Canada: Xanthium commune • USA: P. hysterophorus, X. trifida, X. artemisiifolia, X. psilostachya • Mexico & Caribbean: P.hysterophorus • Laboratory host range: • Mexico: P. hysterophorus, P. confertum, Ambrosia psilostachya, Rudbeckia sp., Bidenspilosa • Australia: P. hysterophorus, Ambrosia artemisifolia, X.strumarium • India: P. hysterophorus, Guizotiaabyssinica • Imported to SA (2010) • Initial strategy: Test host range of agent on the main varieties of G. abyssinicagrown in East Africa

  9. Guizotiaabyssinica • Five main varieties of G. abyssinicagrown in Ethiopia (Kuyu, Shambu, Ginchi-1, Fogera & Esete) • Parthenium hysterophorus • Noog growing areas (mid- to • high altitude)

  10. No-choice trials • Tests conducted in gauze covered cages • 5 pairs of one-day old adults per cage • Duration: 15 days • Plants held in cages for 8 weeks (eclosion ceased) • Dissected & assessed a Tunnellingscores were assessed as follows: 0 – no tunnelling; 1 – 1-30% stem tunnelled; 2 – 31-60% stem tunnelled; 3 – 61-100% stem tunnelled. b Within the same column, asterisks following the mean (±SE) indicate a significant difference (p < 0.05) between the control and the test species; Mann-Whitney U test.

  11. Epiblema damage

  12. Multiple-choice trials • Tests conducted in walk-in cage (5x3x2m) • 10 pairs of one-day old adults • Duration: 15 days (5 day rotation to compensate for effect of light) • Plants held separately in cages for 8 weeks (eclosion ceased) • Dissected & assessed

  13. Multiple-choice trials • Tests conducted in walk-in cage (5x3x2m) • 10 pairs of one-day old adults • Duration: 15 days (5 day rotation to compensate for effect of light) • Plants held separately in cages for 8 weeks (eclosion ceased) • Dissected & assessed a Tunnellingscores were assessed as follows: 0 – no tunnelling; 1 – 1-30% stem tunnelled; 2 – 31-60% stem tunnelled; 3 – 61-100% stem tunnelled. b Within the same column, asterisks following the mean (±SE) indicate a significant difference (p < 0.05) between the control and the test species; Mann-Whitney U test.

  14. Larval development trials • Tests conducted in gauze covered cages • Eggs incubated & placed singly on plants • Plants held separately in cages until adults eclosed Within the same column, asterisks following the mean (±SE) indicate a significant difference (p < 0.05) between the control and the test species; Mann-Whitney U test.

  15. Summary • No-choice: • E. strenuanafeeding damage (larval tunnelling & galling) & larval counts on G. abyssinicanot significantly different to P. hysterophorus • No adults eclosedfrom 4 cultivars of G. abyssinica, possiblydue to insufficient stem tissue to complete development • Multiple choice: • Significantly less E.strenuana feeding damage & larval counts on G. abyssinicacultivars • Lack of adult eclosionon G. abyssinicaagain possibly due to insufficient stem tissue to complete development • Larval development: • Variable gall formation and eclosionof E. strenuanaon G. abyssinicacultivars • Significantly longer developmental times on G. abyssinicacultivars

  16. Conclusions • Decision at SA national weed biocontrolworkshop (2012): • Shelve agent • Compile a risk analysis & publish • Reassess after all other agents have established & been assessed • Further information: • Competitive interactions with other agents? • Conduct open field host range trials (Israel or Australia) • Acceptable levels of damage to noog in Ethiopia? Use of pesticides?

  17. Acknowledgements • Staff: SakhiSambo, MillyGareeb, Derrick Nkala, SamoraMqolombeni, Lynette Khumalo • Funders: DEA (Natural Resource Management Programmes), KZN DAEA

More Related