Vine weevils.

Category: Gardening tips. | Posted: Tue Apr 24, 2007 12:48 am

Many gardeners here in the UK are already beginning to find their plants under attack from these nasties so I thought I'd write a bit about them which may help you recognise the damage they do and how best to deal with them.

The grubs of the VW will attack the roots of almost any young plant in a container so beware!! They are especially fond of primulas and cyclamen for some reason. Plants in the soil are less at risk but are by no means safe from them.

How do you know you have a VW problem?

Your plants will be stunted and will quickly turn yellow and wilt. Unfortunately, at this stage it's usually too late to save them. For an advance warning that vine weevils are about, look for notches bitten out of the sides of leaves by the adult beetles.

What does a vine weevil look like?

The adult weevil is a dark, oval-shaped insect approximately half an inch in length with a blunt snout and long, distinct antennae. In North America, all of the adults are females so every insect has the ability to cause and infestation. Feeding occurs at night; the adults do not fly but instead need to crawl up plants. The larvae are off-white in color with dark heads and can also do extensive damage as they feed on plant roots.

When to look out for them.

The adult weevils emerge from the soil in late May or early June through to mid-July. These adults feed for 4-5 weeks in order to produce the 300+ eggs that are dropped into the ground under the plant. The eggs hatch within 2 weeks and the larvae then tunnel into the soil where they feed on plant roots. They then tunnel deeper into the soil to protect themselves from frost and pupate in the spring.

Understanding the lifecycle and feeding practices of the weevil is the key to keeping the pest under control. Since adult weevils feed on leaves during the night and look for dark, moist spots during the day to rest, trapping them in these areas can be quite effective.

Some tips on how to control vine weevils.

Simply place a white drop cloth under your plant in the evening or early morning and shake the leaves this will help to catch many of the adults.

During the day, place a board under the plant. Check the board for hiding adults and scrape them off into a bucket of soapy water.

The eggs and larvae of the black vine weevil require moisture to survive. If your plants are heavily mulched, pull back this mulch to allow the surface of the soil to dry out and do not water plants unless necessary.

Using Nematodes to conttrol vine weevils.

Rather than attacking the adults, beneficial nematodes go after the larvae in the soil and are a safe and natural method of controlling vine weevils. Follow the instructions to the letter and you should find they really help to reduce or eradicate the weevils from your garden.

Simply type 'Nemasys Vine Weevil Killer' into your search engine to find suppliers.

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Gardenstew wrote on Tue Apr 24, 2007 10:11 am:

Great article Eileen, very well written and informative ;) Have you had much of a problem with vine weevils yourself in the past?

eileen wrote on Tue Apr 24, 2007 10:29 am:

No I haven't Frank but a friend of mine in Dumfries is inundated with the beasties every year and I've spent many a week-end helping her to eradicate them.