The Cactus Working Group was established in 2012 to address the issue of invasive cacti species in South Africa. Managed by the South African National Biodiversity Institute’s Invasive Species Programme, the CWG meets biannually at the National Botanic Gardens in Pretoria.
The CWG is made up of scientists from SANBI, the Department of Environmental Affairs, the Department of Agriculture, Forestry and Fisheries and various universities, as well as certain stakeholder groups.
Successful working group with top scientists
The CWG has been a huge success with the organizational skills of Haylee Kaplan from SANBI. Dr Ana Novoa, a post-doctoral researcher based at the Centre of Excellence in Invasion Biology (CIB) at Stellenbosch University, has contributed significantly to our understanding of invasive cacti and the extent of trade in the nursery industry.
South Africa’s top biocontrol scientists, like Hildegard Klein from the Agricultural Research Institute (ARC), lead the field in biocontrol of invasive cacti form part of the CWG. Other top scientists include Dr Helmuth Zimmermann and Lesley Henderson, who have been instrumental in the success of this working group.
The CWG was privileged to have Dr Roberto Kiesling, a taxonomist and top cactus expert from Argentina, presenting at the April 2016 meeting.
In October 2014, the CWG held a workshop in the heart of historical cacti invasions – Graaff-Reinet in the Eastern Cape.
Members of the CWG, particularly Dr Ana Novoa, were instrumental in launching the International Cactus Working Group during a conference held in Hawaii earlier this year.
The latest meeting was held on Thursday 17 November, 2016.
- Iain Patterson gave an overview of cactus biocontrol research at Rhodes University.
- Madodomzi Mafanya spoke about using remote sensing techniques to detect Harrisia pomanensis.
- Travor Xivuri chaired the session and also reported back on his trip to Australia where he attended the Australasian Weeds Conference in September 2016.
Invasive cacti are a concern in South Africa, particularly in arid regions where they are fast taking over productive agricultural land and game farms. Various species of Opuntia have become serious invaders, but fortunately effective biocontrol such as cochineal have produced fantastic results in the control and spread of these cacti. Teddy bear cactus (Opuntia microdasys) is still often traded despite being listed under NEMBA as a Category 1b invasive species.
Some cacti also thrive in sub-tropical regions with high rainfall, such as Barbados gooseberry (Pereskia aculeata) – Category 1b and the climbing dragon fruit (Hylocereus undatus) – Category 2.
INVASIVE SPECIES TRAINING - Last training sessions of the year...
A two-day training event will be be held in Midrand at Doonholm Nursery on Tuesday 15 and Wednesday 16 November, 2016.
Module 1 (Day 1): Train to become an invasive species consultant
Subjects covered include: NEMBA legislation and Invasive Species Regulations; Landowners, estate agents & lawyers ‘duty of care’; Control plan guidelines for organs of state & protected areas; Permitting, compliance & directives; Invasive species
Module 2 (Day 2): Introduction to herbicides and control methods
Subjects covered include: Invasive species clearing using herbicides; Herbicides and the law; Selecting control methods for invasive species clearing; Professional herbicide training
Time: Registration and coffee - From 08h00
Training times: 09h00am to 16h00
Refreshments: Tea and a light lunch will be provided.
Booking: Booking is essential.
Email your fillable PDF booking form to Hazel at
We will then send you an invoice for payment prior to training.
Entry to training: No one will be admitted to the training without payment or prior arrangement.
Cost per module: R800 (Ex VAT) or R912 (including VAT)
SAGIC invasive species and herbicide training is an entirely self-funding project.
For further information: Contact Hazel at or Tel: 011-723-9000.
Or Kay on
To download a booking form individuals:
To download a group booking form:
The training dates for 2017 will be released in December 2016.
The Department of Agriculture, Forestry and Fisheries (DAFF) has announced that the first sightings of the tomato leaf miner (Tuta absoluta) has been detected in the eastern parts of the Mpumalanga Province, South Africa. This pest is disastrous particularly for tomato production and food security in general.
After almost two years of surveillance by industry role players, Tuta absoluta was detected for the first time from the five surveillance traps in late August 2016, three of which were set in the Southern Kruger National Park, one on a tomato farm near Komatipoort and one at the Lebombo border post. The specimens collected from pheromone traps were sent to the Department of Agriculture, Forestry and Fisheries (DAFF) Plant Health Diagnostic laboratories and the identification was confirmed by a Lepidoptera specialist from the Agricultural Research Council (ARC).
From South America, to Europe and Africa
This pest spread from South America to Europe in 2006 and across to northern Africa. Since then, it has spread throughout the Middle East to India. It was reported in Kenya and Tanzania in 2014 and from September 2016 in Zambia. The DAFF has been closely monitoring the spread of this pest across the world and has proactively initiated emergency actions to register agrochemicals to prepare for a rapid response to any possible outbreak of this pest in South Africa.
This pest cannot be completely eradicated; however it can be contained and suppressed to lower population levels. The DAFF has already engaged with the tomato and potato production industries and the ARC and underscored an urgent need for development of a detailed plan of action. Such an action plan will be shared with all the relevant role players in due course.
For further information, visit the Tuta absoluta Information Network: http://www.tutaabsoluta.com/
Damage to tomatoes
Under poor control measures, Tuta absoluta can cause up to 100% loss of tomatoes and could also, to a lesser extent, affect potatoes. This poses a serious threat to food security, because tomatoes and potatoes are prominently part of the daily diet for many people in South Africa.
This pest can effectively be controlled through the application of good agricultural practices and/ or integrated pest management. To date, several agrochemicals are already registered by the DAFF to control this pest; however, they must be applied judiciously. The biggest challenge with this pest is that it can develop resistance to chemicals within a single season. Therefore, agrochemicals with different active ingredients should be used in rotation and in accordance with the application requirements. A list of agrochemicals registered for Tuta absoluta and information regarding surveillance is available on the DAFF website.
Tomato and potato producers are encouraged to apply good agricultural practices and/ or integrated pest management, i.e. to do field sanitation, use detection traps, scout for this pest and apply relevant registered agrochemicals when necessary, such as when this pest has been detected in a field trap. Please alert the DAFF Early Warning Systems division in case you suspect occurrence of this pest in your area.
International travellers are advised to avoid illegal importation of agricultural commodities into South Africa because this may lead to the introduction of new pests and diseases which are expensive and difficult to manage.