The bean weevils or seed beetles are granivores, and typically infest various kinds of seeds or beans, living for most of their lives inside a single seed. The Bean weevil is found in storage facilities. Bean weevils are not true weevils because they do not have a snout like rice or maize weevils. Bean weevils develop on the mature bean pods in the field but will also infest beans in storage facilities. They develop primarily on common bean but have been found on other beans. This insect is also capable of feeding and reproducing on fungi.
They are 2.0 – 3.0mm long, mottled brown in color. They have a ‘tear drop’ like body shape and are covered in short hairs. Saw-tooth has antennae and elytra that do not cover the entire abdomen.
Lifecycle usually lasts 2-4 months. The larvae feed within the beans as they mature. The larval stage can take from a few weeks to many months to complete, depending upon temperature and moisture of the bean. Pupation is within the bean. Circular holes are cut for the adult to emerge. Development and breeding goes on as long as there is any food left in the bean and the temperature is right (warmer temperatures are preferred).
Larvae feed mostly inside beans. These weevils attack all legumes, including kidney beans, green beans, peas and lentils. Heavily infested peas are often reduced to shells.