‘What are nematodes?’

Beneficial nematodes are naturally occurring microscopic worms, already present in the soil. BASF’s research scientists have isolated five individual species of nematodes that target specific garden pests including slugs, vine weevils, chafer grubs, leather jackets, caterpillars, codling moth and various others.

The nematodes directly attack specific garden pests and offer enhanced results compared with standard chemical products, as they are organic and are watered directly into the soil, meaning they cannot be washed away when the British weather takes a turn. Once an area has been treated, fruit and vegetable produce can be consumed in the normal way, once washed.

These worm-like micro-organisms are typically less than 2mm in length, and each species has its own specific prey, meaning it will target that only prey.

Nematodes are environmentally friendly, organic and are child and pet-friendly.


Overview of products:


This product is perfect for controlling all common species of small to medium-sized slugs in the British garden, or vegetable plot. Starting pest control early in the season ensures that gardeners will target the young slugs growing under the ground before they do any damage.

As nematodes are able to travel through the soil, to where the vast majority of newly hatched and young slugs dwell, they are able to attack them before they are even in sight, unlike slug pellets which only rely on surface feeding pests. One application of Nemaslug will provide up to six weeks control of all common species of small to medium sized garden slugs. The temperature of the soil being treated should not be lower than 5°C.

Application is recommended between March and October.


Nemasys – Vine Weevil

Nemasys Biological Vine Weevil Killer targets the larvae while they are still in the soil and it kills them before they have a chance to cause damage.

Vine weevils are beetles that attack a wide range of plants, both indoors and outdoors, and they are especially damaging to ones grown in containers. It is one of the most widespread, common, and devastating garden pests.

Over autumn and winter, the weevil larvae hide beneath the soil and feed on roots, causing plants to wilt and die, and if they survive, the grown adult weevils will then eat plant leaves during spring and summer, resulting in irregular-shaped notches on the leaves.

Application is recommended between March and October.


Nemasys – No Ants

Ants find their way into homes, under patios, pots and plants, causing a path of devastation wherever they go. The Nemasys No Ants nematodes work slightly different from other Nemasys products as they don’t kill the ants.

Ants do not tolerate the nematodes near their nests and then move their nests away from these areas, they leave the area that has been treated.

It is best to apply this product when ant activity is visible on top of the lawn. To ensure the best results, ensure lawns are moist and the soil temperature is above 10°C.

It’s also important to make sure the lawn and the nests do not dry out for at least two weeks after applying nematodes.

Application is recommended between April to September.


Nemasys – Leatherjacket

Nemasys® Biological Leatherjacket Killer controls newly hatched larvae that attack grassroots resulting in slow growth and yellow patches on lawns.

Leatherjackets are the soil-dwelling larvae of the flies commonly known as daddy longlegs. Daddy longlegs appear towards the end of August and lay their eggs within days. Once they hatch, around two weeks later, the inch-long, legless creatures begin to feed on grassroots and stem bases, devastating lawns and plants. The other major damage is caused by birds and mammals that dig into the turf searching out the young leatherjackets.

To ensure long-lasting results, gardeners must keep the lawn well-watered for at least two weeks after application and when applying, the lawn must be moist and the soil temperature above 10°C.

Application is recommended between August to October.


Nemasys – Fruit & Veg Protection

Nemasys® Biological Fruit and Veg Protection control a wide range of pests including carrot and cabbage root fly, leather jackets, cutworms, onion fly, sciarid fly, caterpillars, gooseberry sawfly, thrips, shore fly and codling moth.

It has the benefit of causing no harm to non-target species, and it can be used on home-grown produce with confidence, as fruit and vegetables can simply be rinsed with water being consumed.

The specific method of application will vary depending upon which of the pest’s gardeners are targeting, so reading the instructions in great detail is recommended.

Application is recommended between April and October.


Nemasys – Chafer Grub

Nemasys® Biological Chafer Grub Killer controls newly hatched larvae in the grass.

Chafer grubs are soil-dwelling larvae of chafer beetles. Depending on the species of chafer, they either feed on decaying plant material or plant roots. Evidence of their activities can be seen in a number of ways. Between autumn and spring, the damage is most noticeable, as grubs are at this point reaching maturing. As with leatherjackets, birds and mammals dig up lawns searching for the chafer grub larvae.

To ensure long-lasting results, keep the lawn well-watered for at least two weeks after application and when applying, the lawn must be moist and the soil temperature above 12°C.

Application is recommended between August and October.


How to use:

For all the products, the application is broadly the same. The nematodes in each of the products work by attacking the pest by entering natural body openings, releasing a bacterium which quickly and safely kills it.

The nematodes reproduce inside the dead and dying pest and release a new generation of hungry nematodes, which disperse and search for further prey.

Below is a basic step-by-step process for using a Nemasys/Nemaslug product.

  1. Before opening the pack of nematodes, ensure that the pests are present and that the soil is above the minimum degrees centigrade.
  2. Once you have confirmed the above, dissolve the entire packet into a bucket of water to create a stock solution. Stir vigorously and immediately take a portion of the stock solution.


  1. Add this to a five-litre watering can fitted with a very coarse rose and then fill this with water.

  1. Apply this solution, a section at a time, to the soil area which requires treatment. Keeping taking portions of the stock solution and adding it into the watering can with water until the whole area is treated.
  2. To finish off, water the treated area(s) after application so that the nematodes are washed thoroughly into the soil.

The amount of water stated on the instructions for each product has been determined by research in different situations. This amount is the optimum required to ensure that the nematodes are applied at the correct rate and washed through the soil to the pest, or to reach where the pest is found.

Once gardeners receive their nematodes, they must be kept refrigerated. The pack will keep up to the expiry date printed on the inner sleeve, but this varies with the product so check with the supplier, if necessary.

Once the contents have been exposed to the air, it is important to use all the pack. Storing the solution mixed with water is not recommended.


Where to buy?

All the products can be brought via several distributors, a list of which can be viewed below:

BASF recommends that gardeners sign up to an extended programme, receiving a delivery every six or eight weeks (depending on the product), so that pest numbers can be kept down throughout the season.

This way, gardeners will be guaranteed a damage-free harvest.


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