Threatened
Plants Programmes: Namibia
Hoodia
What
is Hoodia?
Hoodias (Apocynaceae) are
stem succulents endemic to the drier regions of southern Africa. Ten taxa
occur in Namibia. The status of the different taxa in Namibia varies: H.
alstonii, H. juttae, H. pedicellata, H.
rushii, and H. triebneri are categorised as
vulnerable due to their small population numbers and very limited range.
H.officinalis subsp. delaetiana is endangered. H.
currori, H. flava, H. gordonii, H.
officinalis subsp. officinalis, and H. parviflora
are not threatened at present (Craven and Loots, 2002).
Why
was Hoodia selected?
The plant has recognised
appetite suppressant qualities and a huge potential market for Hoodia-based
dietetics is evolving. This has led to a dramatic increase in the level
of interest in Hoodia species, especially H. gordonii, in
Namibia over the past three years. Requests for plant material have soared
to such an extent that it has triggered alarm in relevant government ministries
and amongst other parties. There was concern that the high prices offered
for plant material and the lack of a national framework for managing and
marketing such material would rapidly lead to the uncontrolled harvesting
of the plants in situ, with devastating consequences for population
numbers.
It
was decided, therefore, that a proactive approach to Hoodia management
needed to be undertaken, to pre-empt the demand for plant material harvested
in situ. This would include propagation trials to establish the germination
and growing requirements of the plants and to assess the viability of cultivating
Hoodia (as a crop)—in
short, establishing a national cultivation programme. This programme would
encourage landowners to participate in the cultivation of Hoodia
plants to meet the needs of the market, while collaborating with research
into the plant to improve management strategies.
The
establishment of “successful and appropriate” propagation procedures and
sites, and the transfer of the necessary propagation and plant maintenance
skills to communal/commercial operators (farmers) was seen as central to
the long-term protection of in situ (“wild”) plant populations.
A
propagation trial was established at the National Botanic Garden of Namibia
(NBGN) as part of the Threatened Plants Programme (TPP), with a one-year
SABONET grant of US$ 3,000.00 and the appointment of a SABONET horticulturalist
to implement and oversee the project.
Implementation
Given
the uneven (steep) topography of the NBGN, space for the propagation of
plants is limited. There are two greenhouses (4m x 2m) and two shaded structures
(8m x 4m). Given the state of disrepair of the shaded structures, the first
activity of the TPP was to revamp the structures. The sides and the roof
were covered with new shade netting, and raised beds were built of brick
and filled with sand. We brought in two different types of sand to mix a
generic germination and growing medium. Flat seed trays were obtained and
many 7.5cm plastic pots purchased.
A
field trip to collect Hoodia gordonii seeds was undertaken to southern
Namibia early in November 2002. Four farms with large Hoodia populations
were targeted and many seeds collected. We kept the seeds from the different
sites separate.
Sponsored
by SABONET, the horticulturist attended a two-week horticultural training
course at the Durban Botanic Gardens, as well as a two-week internship at
Kirstenbosch National Botanical Garden and the Karoo Desert National Botanical
Garden. These activities had a direct impact on the Programme, contributing
greatly to improve our level of skills and equipping us with the specialised
knowledge required for the maintenance of xerophytic plants.
Progress
Once the seeds had been collected, germination activities got underway.
Each individual seed was stripped of its tassel and planted in a seed tray.
The origin of each tray of seeds was recorded on the tray. The seeds were
germinated in the greenhouses. Once the seedlings reached a hight of 1.5
cm, they were transplanted into individual pots under 60 percent shade netting.
After a few weeks, they were placed in the shade houses (40 percent shade
netting) in their pots on the raised beds. This process of germination continued
through the summer, with the last batch sown early in March. By that stage,
some 8,000 seeds had been sown and 4,400 seedlings were growing. A further
batch of seeds was planted in July 2003 during the winter to determine germination
rates during winter. None of the seeds germinated.
In
the meantime, fungus appeared among the seedlings, resulting in the loss
of some, while others did not appear to be negatively affected. Woolly root
aphids also appeared and destroyed a number of seedlings. The use of systemic
fungicides and pesticides was not permitted, as the aim of the germination
trials was to determine the requirements of Hoodia under cultivation
as an organic product/crop. The fungus and aphids were suppressed by using
a diluted solution of bicarbonate of soda. Ants were discouraged by pouring
pesticide around the outside of the structures. This all proved limited
in success and low-level losses still continue to occur.
Nevertheless,
on the whole, the propagation trials have proved successful. It has been
clearly demonstrated that Hoodia plants can readily be germinated
from seeds and grown in large numbers. This can be achieved with minimal
capital outlay and infrastructure development.
There
are, however, some problems. These include fungal infections and woolly
root aphid infestations. The prevention and eradication of these diseases
and pests is limited to organic methods of control. These methods work better
when used as a preventive measure, but are not as effective as inorganic
control methods. Disinfecting the growing medium and the growing area is
also important to reduce pathogens.
Experiences
Probably
the most significant and valuable activity/aspect that the TPP facilitated
was the exposure of the SABONET horticulturist at the NBGN to experts in
this field. Their willingness to share their experience and advice has been
a significant contributing factor to the success of the TPP at the NBGN.
The
road ahead
The TPP
has been a success to date. This is demonstrated by the expansion of the
propagation trial project into a national cultivation initiative funded
by the European Union, and entails the cultivation of Hoodia and
other succulents. The successful outcome of the propagation trials laid
the basis for this. Without SABONET’s TPP it is unlikely that an initiative
of this nature would have emerged in Namibia. It presented an opportunity
for the NBGN to take the lead in contributing to the protection of a resource
that would otherwise most likely have been exploited unsustainably. The
protection of in situ Hoodia populations and the expansion of cultivation
activities nationally to meet the demand for plant material for commercial
purposes, while generating income for rural communities and farmers, should
become evident with time. This will be the ultimate measure of the long-term
success of the SABONET TPP in Namibia.
—Stephen J. Carr
SABONET News
9.1: 43
CRAVEN
& LOOTS. 2002. Namibia. In: J. S. Golding (ed.). Southern African Red
Data Lists. SABONET Report No.14: 61-92
