Vine weevil - Otiorhynchus sulcatus
Vine weevils are grooved, black-brown beetles about 1 cm in size with large antennae that are mainly active at night. They appear from late May onwards. The beetles lay eggs in the soil throughout the summer from which cream-coloured larvae about 1 cm in size emerge. It is mainly these larvae that eat the roots that cause the damage.
Damage description:
The plant shows reduced growth and sallow colour due to the larvae's root feeding. In severe infestations, the yew may die because it has too few healthy roots left. In summer, the needles are eaten by the beetle but this is less noticeable and not so bad for the plant.
Solution:
Controlling the larvae is cumbersome but can be done organically with nematodes. A good soil temperature and sufficient humidity is needed.
The beetle can be controlled during summer and autumn with an appropriate insecticide. This can also be done organically with spinosad-based products. It is important to treat late in the evening because the beetle is nocturnal.
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