Garden Pests Series: V…

…is for Vine weevil.

So, the Garden Pests Series is drawing to a close! Currently our marketing team are brainstorming for a new series of blogs to compile and compose at the conclusion of this one. But that’s talk for another day; the Garden Pests Series isn’t over yet, you’ll be pleased to hear, as this is the 22nd edition out of 26. So pop the kettle on and have some down-time reading about Otiorynchus sulcatus, more commonly known as the vine weevil.

A danger to both indoor and outdoor plants, the vine weevil look somewhat like beetles; they are black with light-coloured patching, wingless and are only 1cm in length. However, if I have learnt anything from my research for this Garden Pests Series it is do not underestimate a pest due to its small size! Vine weevils can be one of the most destructive nuisances to organisms much larger than themselves. If you have numbers of shrubs, small trees and ordinary garden and house plants on your property, beware that both adult vine weevils and their larvae can be very destructive, particularly to plants grown in pots. Adults generally appear between May and June from the soil of outdoor plants and between March and April when they have infested an indoor plant.

You can keep an eye out for them, but another difficulty of their behaviour is that they are nocturnal and only feed at night, making this more difficult. However, a clear indication of a vine weevil infestation are semi-circular incisions along the side of leaves left by the adults. The larvae themselves feed on plant roots, which is potentially more damaging, as they destroy the root system, which can ultimately lead to a plant’s demise. The overwintering larvae also do this, before pupating during April-May. When the cold weather does set in, most adult vine weevils do die, but a female can lay between 500 and 1,500 eggs in the soil, making the battle with the pest an important one.

Vine weevil infestation can fast get out of control, so it is important that you carry out quick and efficient treatment methods. But way of chemicals, products containing thiacloprid – as a soil drench, so in liquid form – are effective against the critter. As always, we recommend you always read the label of any chemical products you are using and to take the necessary PPE precautions. However, if you prefer to adopt organic methods, try these on for size:

• Check weekly for infestations;
• Remove and kill adults during the evening;
• Use netting and fleeces between plants;
• Replant perennials kept in pots during the Spring months, removing any larvae; and,
• Use nematodes, which are available for purchase at a number of vendor, who find and kill vine weevils.

As you’ve probably established yourself, you could do without vine weevils in your garden! Luckily, there are some prevention techniques used by gardeners all over, which are all successful in their own right:

• Dispose of soil in which vine weevil have been found;
• Remove dead plants and examine roots, looking for evidence of vine weevil larvae feeding – if this is found, search the surrounding soil and destroy any you find;
• Look for incisions in leaves, using nematodes during the Summer to control larvae population;
• Avoid using broad spectrum insecticides, which can kill natural predators of the vine weevil; and,
• Encourage insectivorous birds to your garden with feeders and nesting boxes.

 

 

Photo credit: <a href=”https://www.flickr.com/photos/m-a-r-t-i-n/10324424126/”>Martin Cooper Ipswich</a> / <a href=”http://bestmodernchairs.com”>Modern Chairs</a> / <a href=”http://creativecommons.org/licenses/by/2.0/”>CC BY</a>