Invasive species threatening Zimbabwe...Download

Invasive species threatening Zimbabwe
Water Hyacinth (Eichhornia crassipes
Martius) is amonocotyledonous
freshwater aquatic plant, belonging to the
family Pontederiaceae, related to the lily
family (Liliaceae)and is a native of Brazil
and Equador region.
It grows from a few inches to about a met
er in height.
The stem and leaves contain air filled sacs,
which help them to stay afloat in water.
Water hyacinth is considered as anoxious
weed in many parts of the world as it
grows very fast and depletes nutrient and
oxygen rapidly from water bodies,
adversely affecting flora and fauna
Water Hyacinth in Zimbabwe is a threat in
rivers along the Manyame Catchment and
Zambezi river basin
Invasive species threatening Zimbabwe
Lantana camara is a small perennial shrub
which can grow to around 2m in height
and forms dense thickets in a variety of
Due to extensive selective breeding
throughout the 17th and 18th Century for
use as an ornamental plant there are now
many different forms of L. camara present
throughout the world.
The fruit of L. camara is berry-like and
turns a deep purple colour when mature.
Both vegetative (asexual) and seed
reproduction occur.
Up to 12,000 fruits can be produced by
each plant which are then eaten by birds
and other animals which can spread the
seeds over large distances, facilitating the
spread of L. camara.
Invasive species threatening Zimbabwe
• Australian red claw crayfish
(Cherax quadricarinatus) in Lake
Kariba and the Zambezi river basin
• Omnivore, mainly detritus feeder,
but also alleged to feed on eggs of
other fish species and other
aquatic species that form the base
of the trophic triangle in the lake
ecosystem (needs verification)
• Burrower and therefore threatens
the structural integrity of hydroelectric installations
Invasive species threatening Zimbabwe
• The jumping cholla
(Cylindropuntia fulgida)
mainly found in
Matebeleland South
Province with the
severely affected districts
being Gwanda and
• Rapidly spreading to
other arid districts and
threatening livestock and
human settlements
Invasive species threatening Zimbabwe
The jumping cholla (Opuntia
fulgida) segments attached to a
The weed spreads vegetatively and
rarely through seed
The thony plant segments are
adapted to be spread by animal, bird
and human traffic.
Its ecology is largely unknown in the
arid environments of Zimbabwe
Current management strategies
include cutting and burning (EMA)
but the most sustainable
management method is to release
the biological control agent for
Cylindropuntia fulgida, the cholla
biotype of the cochineal insect
Dactylopius tomentosus
Invasive species threatening Zimbabwe
• The black wattle, Acacia
mearnsii De Wild. (Syn. A.
mollissima Willd.; Acacia
decurrens var. mollis
Lindl.) is a major invasive
species in the Eastern
Highlands of Zimbabwe.
• Potentially over 200 000
ha is affected, most of it
in the mist belt of the
eastern highlands (15001900 m altitude)
Invasive species threatening Zimbabwe
• The larger grain borer
trancatus) has already
invaded Zimbabwe from
Tanzania and will be a
major threat to maize
and other cereal grain
stores in Zimbabwe.
Invasive species threatening Zimbabwe
• Thaumastocoris
peregrinus (Hemiptera:
also known as the
bronze bug, is sap
sucking Eucalyptus pest
from Australia that has
invaded Zimbabwe from
South Africa
Invasive species threatening Zimbabwe
• Native to Queensland, Australia,
Leptocybe invasa is currently
spreading through out Zimbabwe
from South Africa
• Adult wasps spread by flight and
wind and introductions can be from
nursery stock
• Severe gall formation and damage
especially to Eucalyptus nursery
• Damaged trees show leaf fall, gnarled
appearance, loss of growth and
vigour, dieback and eventual tree
death (Mendel et al., 2004)
Invasive species threatening Zimbabwe
• The red gum lerp psyllid
(RGLP) (Glycaspis
brimblecombei) is a foliar
pest on red gum eucalyptus
trees (Eucalyptus
camaldulensis) from
Australia that has invaded
Zimbabwe from South
• International transport of
nursery stock is the main
method of spread.
• Adults are strong fliers
Invasive species threatening Zimbabwe
The African invader (or Asian) fruit fly Bactrocera invadens,
has recently invaded Africa from Sri Lanka. It had spread to
more than 10 countries in Africa, including Mozambique,
Zimbabwe, South Africa and Namibia.
This fruit fly is highly invasive with a high reproductive
potential, and has a long list of host plants, including citrus,
mango, cashew, papaya, guava, pepper, and several wild
host plants. The main pathway for fruit flies to spread from
one country to another is through the international
movement of infested fruits.
Its base colour is blue-black with yellow patches in the midsection, and a couple of paler stripes on the abdomen. Eyes
are blue-black, and wings are clear with prominent, dark
leading edges.

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