| Common
names: |
No vernacular
names have been recorded. |
| Host plants: |
Mainly plants of the Malvales: Okra, Cotton, Hibiscus, but also rice
and maize. |
Pest status:
|
The pest status of spiny bollworm
in Namibia is still unknown. Cotton is a new crop under promotion in the
country and spiny bollworms may become more common as the cotton growing
area increases. |
Distribution:
|
The first specimens were reared
from cotton bolls collected during year 2000 at Okankolo (Ondiikalela
project) in Oshikoto region and Omundaungilo, Ohangwena region. The samples
were not larger than usual (about 10 affected bolls) but a large number
of spiny bollworm moths hatched from these samples. |
Description:
|
The caterpillar grows to a length of 15-18 mm long and is greyish with
black spots and markings. Note the characteristic spines on the body.
The adult moth has a wingspan of 20-22 mm. The wings are straw coloured
with a few distinct lines across the front wings. In other countries these
species are reported to have green wings or fields of green across the
wings but the specimens from Namibia did not have the slighest sign of
green. The colour depends on temperature and other environmental factors. |
Control:
|
No control is recommended until the pest status of spiny bollworm has
been established. |
Other notes:
|
Bollworm species have quite different eating habits so it is important
to know which bollworms are common (or will become common) on cotton in
Namibia. Some species can feed on many different crops or weeds while others
are fully dependent on the presence of Cotton or a few related species.
A good pest control strategy can therefore only be implemented when we
know which species are occurring.
It is quite easy to rear bollworms from cotton bolls: Collect a few
handfuls of large bolls which have holes in them. Place the bolls in a
single layer in a container with 5 cm of sand in the bottom and place a
net over the container. Clearly label each sample with locality, date,
crop (cotton bolls) and collector. Inspect the containers regularly for
hatching moths. Note that the cotton bolls often get mouldy if they are
too close to each other. |
