Stalk borers are pest insects and can
cause maize yield losses of up to 30%. They are
0.5 to 2 cm long white-yellowish caterpillars that first feed on maize tips,
and later in the maize cob and maize stalk. The damaged plant appears stunted
with broken tips and slightly yellowed upper leaves. The plant cannot produce
yield as the upper broken part dries.
Stalk borer adults are moths that
do not cause any damage. They
lay eggs on the tips of maize plants about 40 days after the crop is planted.
eggs then hatch into larvae which tunnel from the tip of plant through the stalk/stem.
The larva changes into a pupa (inside a cocoon) and later emerges as a new
moth. The larvae live in the stalk, feed on its content and then wait in the
stalk until the next cropping season. Stalk management techniques help to
control the stalk borer larvae and pupae so that there is minimal population
build-up for the next cropping season. The technology is feasible, cost
effective and protects the environment, while reducing the use of pesticides
to control stalk borers.
harvesting the crop, a massive cutting down of stalks should be carried out
in the whole village or farms:
- Cut down the stalks at the
ground by hand hoe, chop them with a knife or break them, and spread them in
- The heat from the sun and soil
surface kills the larvae and pupae in the stalks
- Some larvae are eaten by
ants and birds
- The stalks could also be
grazed by livestock, but make sure that no stalks remain standing in the
- Cutting the stalks kills
up to 95% of the dormant larvae and pupae per season
If only a few farmers
are practising this technology, then it may not be effective because the larvae
from standing maize stalks in neighbouring farms could pupate, become adults and
infest the crops of other farmers who did practise stalk cutting.