Dried bean weevil

(Acanthoscelides obtectus)

Biology:

The pear-shaped dried bean weevil grows up to 5 mm long. It is brownish in colour and has long, light grey flecks on its wings, which leave the last band of the abdomen uncovered. It has greenish-yellow hair on its upper side. The adult weevils can fly well.

The eggs are laid loosely between the stored nutritional substrate. In warm countries, this even happens in the field on the ripening beans. The larvae bore into the seeds of legumes (beans, peas, etc.) and also pupate there.

This weevil species is very thermophilic. It cannot hibernate outdoors at our latitudes.

 

Damage:

When it comes to the nutritional substrate, the weevils prefer beans, but they also infest other legumes (peas, lentils, vetches and more). They cause damage by eroding the seeds – you can find larvae, pupae and young weevils inside. Depending on the size of the beans, you might find up to 20 larvae inside! After the beetles fly out, the seeds are left with circular exit holes.

In addition to this, once they have been infested, the germination capability of the legumes is significantly reduced (problem with seeds).