Effective Treatment For Vine Weevil

Treat Vine Weevil With Parasitic Nematodes

 Vine weevil (Otiorhynchus sulcatus) is a bane of the vegetable grower’s life. Plenty of pot grown plants have just withered away because their roots were devastated by this insect’s larvae. One of the worst affected tend to be pot grown Impatiens and Fuschias. They usually feed underground on both roots and stem-bases which slowly weakens the plant and eventually kills it. If it doesn’t recover after watering, it’s more than likely that weevil larvae is present. A careful inspection of the soil in the pot usually reveals the culprit.

Four small white grubs of vine weevil on the soil surface.
Vine weevil larvae.

The larvae have a distinctive ‘C’ shape, are cream coloured with a brown head. If I find them, I feed them to the robins as a juicy treat. The larvae are especially active from late summer onwards. If you find leaves with cut notches and curves in them then you can accurately predict that vine weevil adults are in the vicinity.

One natural way is to encourage birds to work their feeding magic in the garden. Another is to inspect prize plants at twilight with a torch and pick off the adults to dispose of them.

Vine Weevil Killer: Parasitic Nematodes

One effective way to control them is to use parasitic nematodes (Heterorhabditis sp.). These are microscopic and transparent worms which infest the larvae and feed on their internal tissues. This weakens them, stops them feeding and ultimately kills them.  The packets of nematodes are easily applied as they are activated by water. They are applied to moist compost or soil in the months between August and October. A second treatment is applied between April and May. These months are when the vine weevil larvae are present and the soil is above 5ºC. If applying under cover the pest’s lifecycle is broken and can be applied at any time, as long as the soil is also above 5ºC.

Groves Nurseries are offering Nemasys® Vine Weevil Killer which are parasitic nematodes for the treatment of vine weevil larvae and are offered in amounts suitable for treating either 10 m sq. or 100 m sq.

N.B. This article contains links to our affiliate marketing partner. Please check our affiliate disclosure. Clicking on the surface area fro treatment will take you to their web-site to purchase their treatments.