Plantwise Factsheets for Farmers
Attract ants against white stem borer in coffee
Monochamus leuconotus (syn. Anthores
Recognize the problem
coffee white stem borers (CWB) are dark-grey and white-grey beetles up to 3 cm
long with long dark antennae. Adult beetles are difficult to find, but can
sometimes be seen on young leaves and green twigs.
The 2 to 3 cm long
pencil-thick young, called larvae, are white-yellowish. They feed inside the
stem. You may find small holes in the bark, which lead to tunnels in the stem.
Wood shavings, bark ridging (raised bark), dying of plant parts and wilting at
dry weather indicate larvae damage
lay tiny eggs under the thick bark of old coffee stems, half a metre from the
ground. They lay their eggs just before the short rain season (before August in
the highlands and around July in the lowlands). Larvae hatch after 3 weeks and
bore into the stem under the bark. This feeding reduces nutrient and water
transport from the soil into the plant. Larvae are difficult to control because
they are hidden in the stem. Adult beetles emerge through holes from the tree
trunk at the onset of rains. Adult beetles do little damage.
regularly for wood shavings and bark ridging
between September and November in the northern zone, and between February and
May in the southern highlands of Tanzania.
for holes on the trunks from 1 ft (30 cm) up to 3 ft (1 metre) above the
strong wire to poke deep into the small holes on the trunk to kill larvae
holes in the trunks with wool cotton plugs dipped in chlorpyrifos-based
insecticides. This will kill the larvae in the tunnels. Wear gloves, because
chlorpyrifos is also toxic to you.
method is to smear small wool cotton balls with hot animal fat from meat
Then stick 1 ball each right next to or below a larva entry hole on the trunk.
Do not close the holes. If balls do not stick, fix them with thin rope
attracts ants which will enter tunnels, and eat the coffee borer larvae in the
also just smear hot animal fat next to the holes without cotton balls. But this
does not last so long as fatty cotton balls.
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
The recommendations in this factsheet are relevant to:
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