Banana weevils are a major constraint for
banana cultivation. There are two types of banana weevils which cause damage to
the pseudo stem (stem weevils) and corm (corm or Rhizome weevils).
Larvae bore into the plant and feed on the
stem and corm tissues, making tunnels. As a result of this damage, plants show
growth retardation with yellowing of mature leaves. The infested plants tend to
topple over at the soil level and lodging occurs at the point of pseudo stem
damage. Tunnels and different life stages of weevil can be observed in both the
rhizome and pseudo stems.
Black corm weevils are about 10-14 mm long
and are found on the rhizomes and on the stem near the base of the plant. The
reddish brown stem weevils are about 18-20 mm long and lay eggs only on pseudo
adults can crawl or fly short distances in the plantation and tend to be
attracted to the secretions/ latex excreted by wounds and cut ends.
are two types of traps.
fresh pseudo stems from harvested plants
2 foot long pieces of stem longitudinally into two halves
pieces are placed at different locations in the field, placing the cut surface
to the soil. 30 such traps are recommended for one acre.
and the weevils inside them are destroyed by burning every two weeks. Place new
traps if damage persists.
Type 2 – Stem trap with
- Cut fresh pseudo stems
into 6-10 cm slices
- Spread 6g of Diazinon 5% G
over the cut surface of a one slice, place several pebbles on top, then place
another slice of the same size on top of that. The pebbles in-between the 2
slices will stop the direct touching of the pseudostem slices and allow weevils
to enter. 25 traps /acre are recommended.
- Adult weevils attracted to
the traps die due to the effect of insecticide
- Replace traps fortnightly
until the weevils are under control
For a better control
introduce traps at early stages of plantation.