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ON FARM LEVEL
Integrated pest control
Early detection and proper timing of an insecticide application are
critical. Note that frass can create a ‘plug’ in whorl which prevent
penetration of insecticide. The earlier the larvae are detected and
the smaller the larvae, the better control with insecticide application.
Chemical control
In the US control of the fall armyworm has depended exclusively
on insecticide for many years. As a result, fall armyworm has devel-
oped resistance to major classes of insecticides in the US. The first
resistance reported was to carbaryl, but resistance to parathion-me-
thyl, fluvalinate, Lambda-cyhalothrin, carbamate, organophosphates
and pyrethroid has also been reported. Again this emphasise the
possibility of fall armyworm developing resistance to insecticides
and that label instructions should be followed.
It is also important not to rely on one control practice. Integrated
pest management should always be kept in mind. In collaboration
with the Department of Agriculture, Forestry and Fisheries (DAFF)
a list of insecticides registered to control fall armyworm is available
(
Table 1
).
Genetically modification
Bt technology has been used to control fall armyworm with success
in other countries, however to protect the technology it will still be
important to scout for damage in the crop and to have additional
control strategies in place. Resistance of fall armyworm to Bt maize
has been reported in Puerto Rico, Brazil and the south-eastern re-
gion of the US. Therefore, insect resistance management and inte-
grated pest management are still important.
Natural enemies
Because the fall armyworm is invasive in Africa, it is not yet known
which natural enemies will play a role in attacking this species.
However, the nuclear polyhedrosis virus is an important mortality
agent for fall armyworm in the US. A total of 63 individual parasi-
toids are also reported, which belongs to the two orders of Diptera
and Hymenoptera, as well as potential pathogens and predators in
Latin America.
Pheromone lure
Pheromone traps can be used as an early warning. To optimise
pheromone lure captures for fall armyworm, it is essential to have
the correct blend of components. Therefore, if pheromone traps are
used it should be kept in mind that the two strains of fall armyworm
have differences in sex pheromone composition and
that the different combinations in the lure can affect
the amount of male moth captures.
The invasion of the fall armyworm
6: The African bollworm,
Helicoverpa armigera
.
7: The false armyworm,
Leucania loreyi
.
8: The common cutworm,
Agrotis segetum
.
6
7
8
Figure 1: Distribution of fall armyworm in South Africa and the crops that were attacked.
Source: DAFF, JanHendrik Venter
Mei 2017
54
Scan the QR code for
a list of insecticides
registered to control
fall armyworm.