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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

The Pereskia stem-wilter, Catorhintha schaffneri (Coreidae), a new biological control agent for Pereskia aculeata (Cactaceae). Eighteen months since release, where are we now?

The Pereskia stem-wilter, Catorhintha schaffneri (Coreidae), a new biological control agent for Pereskia aculeata (Cactaceae). Eighteen months since release, where are we now?
Pippa MUSKETT, Iain D. Paterson
Biological Control Research Group, Department of Zoology & Entomology, Rhodes University, Grahamstown

Catorhintha schaffneri Brailovsky & Garcia (Coreidae), a biological control agent for the invasive alien plant, Pereskia aculeata Miller (Cactaceae), was first released in South Africa in 2014. The first releases resulted in variable success with establishment at some sites but populations quickly dying out at others. This study aims to determine which factors may impact establishment success so that release efforts can be optimised. Climatic conditions were investigated in an experiment where 30 adults were released at sixteen sites in different climatic zones. Establishment through winter was only recorded at two sites, one in Amanzimtoti and another in Port Alfred. Low establishment rates were likely due to the low release effort at all sites. The fact that the population survived winter in a relatively cold site, such as Port Alfred, indicates that the thermal tolerance of the agent is likely to be suitable for it to survive winter at most sites, given that P. aculeata is most abundant in the warm sub-tropical parts of the country. The importance of release effort was investigated in another experiment where low release effort (30 adults), medium (60 adults), high (120 adults) and multiple releases (30 adults released every week for four consecutive weeks), were tested. Establishment was successful at all the multiple release sites, only 33 % of sites with releases of 60 and 120, and 16 % of sites where 30 adults were released. By conducting multiple small releases at each site the establishment success rate for C. schaffneri will be increased.

Read 2985 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


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