Treatment against Otiorhynchus larvae

Otiorynchus larva in the ground, like a short white worm or caterpillar

This little Otiorhynchus larvae, a kind of white worm, is also called “weevil”. It sets up its nest in root crowns of flowers, ornamental plants and vegetables.

Even though it isn’t considered fatal or threatening for a plant’s life when only a few bugs appear, if ever numbers rise and stay for a long time it can become dangerous.

How can one recognize if this larva has infected a plant?

Small insects, like white maggots, tunnel around the roots to feed on rootlets and the root crown.

They slowly add on more and more thin tunnels, destroying the root system in the process and slowing the plant’s growth, weakening it.

How to fight these white maggots?

There is no specific treatment tailored to target only these Otiorhynchus larvae.

Some recommend to spray treatments normally applied against vegetable flies.

Adult otiorhynchus beetle, here a black vine weevilA more elaborate solution that has proven its effectiveness is to harness nematodes to get rid of this insect. Coming by these nematodes is a bit difficult, though.

Use only for potted infections, because nematodes are parasites for a good many other insects in your garden, even useful ones.

See also

Image credits (edits Gaspard Lorthiois):
CC BY-NC 4.0: jrcarrington
CC BY 2.0: David Short