×

Warning

JUser: :_load: Unable to load user with ID: 504

Notice

Thank you for visiting our website.

Please note that the site is not fully functional at the moment as we are in the process of re-developing. We hope that you will find the available resources helpful in the meantime.

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

1 2 3 4 5 6 7

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

The potential of Hydrellia egeriae sp. nov. (Diptera: Ephydridae) as a biological control agent for the submerged aquatic weed, Egeria densa Planch. in South Africa

The potential of Hydrellia egeriae sp. nov. (Diptera: Ephydridae) as a biological control agent for the submerged aquatic weed, Egeria densa Planch. in South Africa
Rosali Smith, Julie A. Coetzee, Rosie Mangan
Biological Control Research Group, Department of Zoology & Entomology, Rhodes University, Grahamstown

Egeria densa Planch. (Hydrocharitaceae) is the widest established invasive submerged aquatic weed in South Africa. Native to South America, it forms dense stands in water bodies, prohibiting water usage and threatening indigenous biodiversity. Surveys in its native region yielded a promising biological control agent, a leaf-mining fly from the Ephydridae family, Hydrellia egeriae sp. nov. The damage capacity and host-specificity of the fly was investigated to determine its potential as a biological control agent in South Africa. Larvae consumed on average 14.8 ± 0.6 whole E. densa leaves; feeding from the crown of the shoot downwards. Damaged leaves are susceptible for further pathogenic infection resulting in shoot dieback. Density tests showed that larvae placed at densities of 1, 2 and 5 per shoot had 100% survival rate, while 8 larvae per shoot resulted in a lower survival percentage. No-choice tests showed a small degree of larval feeding and development on non-target species within the Hydrocharitaceae and Potamogetonaceae families. However, during paired-choice tests, H. egeriae showed a strong preference for E. densa. Oviposition site selection ranged predominantly from protruding E. densa leaves to any other surface or plant material available. Larval survival was not affected by oviposition site, as larvae readily moved to E. densa leaves after eclosion. Damage inflicted by H. egeriae is significant, and given it’s specificity for E. densa, should be considered for release in South Africa.

Read 2988 times Last modified on Tuesday, 03 May 2016 12:29

General News Updates

2019 National Symposium on Biological Invasio…

26-02-2019

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

22-01-2019

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

04-09-2018

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?

01-03-2018

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

28-02-2018

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

25-01-2018

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