NEWS
Biocontrol for Yellow Bells
T
o control the spread of
invasive Yellow Bells,
Tecoma stans, the
Weeds Research
Division of the Agricultural
Research Council has
released Pseudonapomyza sp,
which is a leaf mining fly.
The fly was brought in from
Argentina and, after all the
necessary tests and precautionary measures were taken,
it was concluded that
Pseudonapomyza sp was
sufficiently host-specific to be
introduced to target the alien
plant in South Africa. It was
released in four provinces,
including Gauteng.
It is a small, black, shiny fly
with red compound eyes.
Both larvae and adults feed
on the leaves of the Yellow
Bell. The larvae cause
extensive damage by mining
the leaves, while the female
adults puncture the leaves to
deposit their eggs and feed on
the oozing sap from punctured leaves.
It is hoped that once populations of the leaf-mining fly
become established, they will
reduce plant vigour in the
field and also reduce plant
biomass.
Yellow Bells is an ornamental,
densely leafy evergreen shrub
or small tree, which can grow
up to 4m high. Leaves are
bright green above, paler
below, with sharply toothed
margins. The bright yellow,
showy, trumpet-shaped
flowers bloom from October
to May. It develops brown,
shiny fruit capsules, 12-20cm
Yellow Bells
long, that split open to
release papery winged seeds.
The plant competes with and
Continued on page 11
POULTRY DISEASE
Vaccination of adult plot birds
From page 8
1 000 birds and costing less
than R50.
For smallholders with only a
few backyard chickens the
simplest vaccination technique is to mix the vaccine
into the birds' drinking water
and encourage them to drink
a good fill by allowing them to
become thirsty beforehand,
by withholding their water for
a few hours.
10
www.sasmallholder.co.za
should be done twice yearly,
in about July/August and again
in the new year, but vaccination can also be done now,
given the outbreak.
A suggestion is to share a
batch of vaccine among
neighbouring plots
For larger flocks, and for
broilers, etc, a more comprehensive vaccination scheme
should be followed.