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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

Interactions between two biological control agents of Pereskia aculeate

Interactions between two biological control agents of Pereskia aculeate
Zezethu MNQETA1, Iain D. Paterson1, Steve Compton1,2
1Biological Control Research Group, Department of Zoology & Entomology, Rhodes University, Grahamstown, 6140 South Africa
2School of Biology, University of Leeds, LS29JT, UK

Pereskia aculeata Miller (Cactaceae) is an alien invasive plant introduced into South Africa from Brazil. In South Africa, it is a problematic plant that has negative impacts on native biodiversity. Pereskia aculeata has two biocontrol agents, Phenrica guerini Bechyne (Chrysomelidae) and Catorhintha schaffneri Brailovsky & Garcia (Coreidae), released against it in South Africa. This study evaluated interactions between the agents, by investigating whether both agents, individually or jointly, enhanced or reduced the impact on P. aculeata. Potted P. aculeata plants were exposed to one of four treatments: control (no agents), P. guerini only, C. schaffneri only and both species in combination. Four stocking densities ranging from 2 to 12 insects per plant were used. Plant parameters including the change in number of leaves and change in shoot lengths were recorded. Catorhintha schaffneri alone at high densities was more damaging than other treatments with a significantly greater reduction in the number of leaves (-11.7 ± 1.29) and the shoot lengths (-2.17cm ± 0.75 cm) in this treatment. Even at lower density treatments, the combination of the two agents was not significantly more effective than C. schaffneri alone and C. schaffneri was always more effective than P. guerini alone. Mortality of P. guerini (14.7 ± 2.39) was significantly higher than C. schaffneri (6.20 ± 0.90) at all stocking densities when in combination. Catorhintha schaffneri should therefore be the priority species for further mass-rearing and releases on P. aculeata.

Read 3095 times Last modified on Tuesday, 03 May 2016 12:17

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


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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


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