Adult Vine Weevil Trap

Nemastop and Adult Vine Weevils

 

Otiorhynchus sulcatus 23 8 2007 20 10 41

 

Introduction

 

With the decline in the number of available chemicals to control pests such as Vine Weevil (Otiorhynchus sulcatus) many gardeners and growers are now turning to nematodes. These are microscopic sized worms that can attack and kill much larger insects such as weevils. With the launch of the new formulation of nematodes in 2018 in Brazil it has now been possible to incorporate them in a special formulation that can be applied to grooves in a wooden trap.

 

 

Each trap is made up of a specifically designed wooden board with three grooves in it, these are filled with the new gel containing more than 2.5 million nematodes (Steinernema carpocapsae). This gel attracts the adults, which are then attacked by the nematodes internally and die. Each trap is sufficient to cover about 10 m² or 5 m of hedge bottom, the nematodes will remain active for up to 6 weeks or longer if there is a plentiful supply of adult weevils.

 

Heuchera with Vine Weevil

 

The boards should be placed directly on the ground underneath your plants and the adult beetles will crawl into the grooves looking for shelter during the day as these weevils are nocturnal and will look for any sheltered cool and dark spot to hide during the day. The nematodes in the gel will infect the weevils and safely kill them without harming anything else. These traps are not only safe in the garden environment but are safe for children pets and wildlife.

 

black Weevil Damage

 

They can be used where adult vine weevils are present, such as in hedge bottoms around the base of susceptible plants such as fuchsias, strawberries, primroses and many other plants such as succulents.

 

They can be used for protecting hedges such as privet on the patio where vine weevil is may attack the roots of many container plants and on raised beds and in greenhouses and other protected structures.

 

Nemastop 2

 

The Nematop trap is ideally placed in situ between late May and September this will help to dramatically reduce the number of adults which in turn will reduce the population of vine weevil larvae that can cause so much damage in our gardens and pots devouring roots causing plants to wilt. Most good retailers of nematodes will therefore only sell you this product from late May until early September. Be aware research shows some online retailers offering them in late November, here I would only recommend them for indoor use such as heated greenhouses.

 

Many of us will have seen the typical unsightly angular shape notches taken out of leaves on many plants such as rhododendrons, camellias and many other shrubs and herbaceous subjects. The adult will lay eggs in April and May and again in August and September and will be active throughout the summer. Each adult, lay up to 1500 eggs each summer with adults living to 4 or five years of age they will overwinter in protected environments rarely moving or feeding so attempting to kill them while they are inactive is more difficult combined with the fact that the nematodes are less active at lower temperature.

 

This product is probably best in use alongside the existing nematode solutions such as Nemasys which are watered onto the soil or compost around susceptible plants from May until September. They are very effective if used correctly and when no other chemical control has been applied to the soil for some considerable time. Being so small, these nematodes are easily killed if any soil-based insecticide has been added in recent months. It is often best to use nematodes shortly after potting all repotting plants for best effectiveness.

 

Observations

 

A good friend posted images of dead adult weevil bodies on social media, clearly indicating they work even in late autumn see image below

 

Dead Vine Weevil

Dead Adult vine Weevils after trap was placed close to them

 

One site carried 68 comments, a huge majority found them both useful and effective

 

Suppliers

 

Agralan  Vast range from this long-established company.

 

Bionema

 

Defenders (Wyebugs)

 

Dragonfli Very exhaustive list of biological controls Inc for mealy bug

 

Fargo  A trade supplier

 

Gardening naturally Offer a wide range of plant care and protection product

 

Green Gardener Huge range of organic products

 

Ladybirdplantcare  Good reports on this supplier

 

Nematodes Direct  One of the UK's largest suppliers of nematodes

 

Organic Gardening Catalogue

 

Royal Horticultural Society  Suppliers of Biological Controls list in PDF format

 

(C) 28/11/2021 Howard Drury

 

 

 

 


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