Bean weevil: treatment and prevention

BThe weevil is the larva of theAcanthoscelides obtectus. It grows in the dry beans of beans, depriving them of their germinating faculties and making them unpalatable.

Zoom on the prevention and treatment of the bean weevil!

The bean weevil: Acanthoscelides obtectus

This beetle is part of the Crysomelidae family, a subfamily of the Bruchinae. Adult insects are brown in color, have three pairs of legs and two antennae. They are between 3mm and 4mm long. The larvae are white, plump and have a small brown head.

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Life cycle

In the spring, female insects lay over 30 eggs on or inside the grains. After two weeks, a larva appears and enters the interior of the dry beans. To enter the grain, the larvae dig small holes, until they form a kind of Gruyere. It spends its various larval stages indoors before pupating to make way for the adult insect. The latter will then emerge and reproduce, thus producing several cycles per year. There are up to three generations a year, which is what makes this pest so formidable. When the first cold weather arrives, the insect takes refuge again in the dried beans to spend the winter.

Symptoms and damage

The larvae only enter dry grains, fresh beans have nothing to worry about. By tunneling inside the grains, they become unfit for consumption. You can't use them for seed either. The harvest is thus lost! Be aware that there are several varieties of weevils that attack different plants. TheAcanthoscelides obtectus affects beans, other Bruchidae attack lentils, broad beans or peas.

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Prevent the appearance of the bean weevil

Freeze the grains

When harvesting, pay attention to your grains, remove any that appear damaged. Then let them dry for a few days, before placing them in the freezer for a week. By freezing them, you will eliminate any larvae, eggs and adult insects that may be present. All you have to do is store them with peace of mind.

Decoction of tansy

You can deter insects from going to your beans to lay their eggs with a decoction of tansy. Indeed, its smell would repel these pests. To do this, collect 300g of tansy which you finely chop and place in a non-metallic container. Pour a quart of boiling water over it, then cover. Leave to infuse for 24 hours. All you have to do is pour this solution into a bottle using a Chinese to filter. Use your spray decoction at the base of your beans.

Healthy seeds

After harvest, immerse your grains in water and remove any that are floating. Do not put them on the compost, burn them as soon as they are dry.

Bean weevil treatment

There is no treatment available to eliminate bruchids once they are installed. However, you can still try to scare them away. Then place garlic cloves or tansy flowers with your seeds. Their strong odor is likely to repel pests. Remember to store your grains well in airtight jars, so that no insects can come and lay eggs.

Video: Grain Weevil Robot (September 2021).