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German wasp | Vespula germanica

German wasp

Vespula germanica

Coral bush | Ardisia crenata

Coral bush

Ardisia crenata

Purple loosestrife | Lythrum salicaria

Purple loosestrife

Lythrum salicaria

Pom pom weed | Campuloclinium macrocephalum

Pom pom weed

Campuloclinium macrocephalum

Canarybird bush | Crotalaria agatiflora

Canarybird bush

Crotalaria agatiflora

Peanut butter cassia | Senna didymobotrya

Peanut butter cassia

Senna didymobotrya

Rubber vine | Cryptostegia grandiflora

Rubber vine

Cryptostegia grandiflora

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Environmental Programmes

In order to tackle our country’s socio-economic challenges, the government adopted the Outcomes based approach to improve government performance and providing focus on service delivery. find out more

Host specificity testing of congeneric species of leaf-mining flies, Hydrellia pakistanae (Diptera: Ephydridae) and Hydrellia sp. – two candidate biocontrol agents for Hydrilla verticillata (Hydrocharitaceae) in South Africa.

Host specificity testing of congeneric species of leaf-mining flies, Hydrellia pakistanae (Diptera: Ephydridae) and Hydrellia sp. – two candidate biocontrol agents for Hydrilla verticillata (Hydrocharitaceae) in South Africa.          Angela Bownes
Agricultural Research Council – Plant Protection Research Institute (ARC-PPRI), Private Bag X6006, Hilton, 3245, South Africa

Hydrilla, Hydrilla verticillata is a submerged aquatic macrophyte, native to Asia and Australia that has invaded South Africa, and which is a serious economic and environmental aquatic weed. Hydrilla is genetically diverse, with a wide distribution in its native range hence biotype matching was an important consideration for the biological control programme. Two leaf-mining flies, Hydrellia pakistanae and Hydrellia sp. of different origins have been under consideration for release against South African hydrilla, a monoecious biotype of Malaysian/Indonesian origin.   Hydrellia sp., was considered the better match for S.A. hydrilla due to its origin on monoecious hydrilla from Singapore and was therefore the focus of host specificity testing. Additionally, comparative studies showed that Hydrellia sp. performs better on S.A. hydrilla compared to H. pakistanae, which originates on Indian dioecious hydrilla. Host range testing focused on ecologically similar and closely related species to hydrilla within the order Alismatales. Hydrellia sp.’s host range was also compared to H. pakistanae, on ‘susceptible’ non-target species to supplement the performance data which led to a decision reject H. pakistanae as a biocontrol agent for hydrilla in South Africa. Test plant species within a closely related genus, Lagarosiphon proved to be the most susceptible to both fly species, supporting complete larval development to varying degrees. However, choice tests and host suitability trials with Hydrellia sp. demonstrated a distinct preference for its host plant as well as limited potential to establish viable populations on the non-target species. Overall, there were minor differences in non-target host use between the two fly species, further supporting the decision to reject H. pakistanae. Hydrellia sp. is considered to pose no risk to native aquatic plant species in South Africa and is thus a promising candidate for biological control of H. verticillata.

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General News Updates

2019 National Symposium on Biological Invasio…


This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more

2019 Invasive Species Training


During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa.  ... Read more

Alien Grass Working Group


Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more

Permits for planting indigenous Cynodon?


On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species.  Updates to the draft&n... Read more

Invasive species training 2018 dates released


Interested in invasive species?  How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more

Communications post for Africa advertised


The Nature Conservancy has advertised a brand new post:  Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below:    Job Titl... Read more