Biology Reference
In-Depth Information
utilising cutting and burning to control alien plants including parthenium are being
practiced in Swaziland. However, long-term effectiveness of such methods in reduc-
ing parthenium abundance is unknown. Management practices were successfully
implemented in Mlawula Reserve in northeastern Swaziland to improve the condition
of the vegetation in overgrazed areas with dense infestations of parthenium by lower-
ing game levels and therefore reducing overgrazing and the incidence of parthenium
(Bowen 2001). In protected Nature Reserves, use of more aggressive and or non-
native plants to displace parthenium is often not encouraged. An approach incorporat-
ing classical biological control and grazing management (Table 12.5) is more suitable
for managing parthenium in protected forests and nature reserves.
12.5.4
Wasteland and Roadside
In all countries where parthenium is known to occur, it is widespread in wasteland,
fallow and roadside areas where control options often do not provide any economic
returns. Hence, in many countries, no concerted efforts are being made to manage
parthenium in these areas. However, parthenium infestations in these areas appear
responsible for the spread of the weed to new areas, and hence managing parthenium
in these areas would greatly reduce the chances of further spread. In Australia, a
robust roadside management program using herbicides is in operation in majority
of the local Shires and Councils where parthenium is known to occur. Research is
in progress in Australia to identify suitable native plants to competitively displace
parthenium in these areas. In India, competitive displacement of parthenium by
other beneficial plants has been widely attempted in several states (Gautam et al.
2005a; Joshi, 1991a, 1991b; Kandasamy and Sankaran 1997; Kauraw et al. 1997;
Sushilkumar and Bhan 1997). However, the long-term impact of such programmes
is not fully known. Required management options for parthenium differ markedly
between countries, but essentially include biological control as one of the options
in all countries (Table 12.5).
12.5.5 Urban Areas
Parthenium is prominent in majority of the towns and cities in India, and it has the
potential to become a major urban weed in other countries also (e.g. Bangladesh,
Ethiopia, Kenya, Mozambique, Pakistan, Sri Lanka and Zimbabwe). In India,
parthenium infestation in urban areas is responsible for causing severe human
health problems such as contact dermatitis and allergic rhinitis (e.g. Kololgi et al.
1997; Handa et al. 2001; Sharma et al. 2005; Sashidhar et al. 1997; Towers and Rao
1992). But no management program is in place in most of the towns. A similar situ-
ation appears to exist in other countries also. In Australia, though parthenium is not
a problem weed in urban areas, there are ongoing campaigns through television and
