BASF Agricultural Solutions UK

Nemasys L


Nemasys® L contains the beneficial nematode, Steinernema kraussei and provides effective control of black vine weevil larvae (Otiorhynchus sulcatus) in soft fruit and ornamentals.


  • Nemasys® L can be used in organic systems or as part of an IPM programme
  • Safe to users and the environment
  • Nematodes survive up to approximately 4 weeks in the soil
  • No pest resistance problems
  • Gives high levels of control between 5°C - 30°C
  • Simply applied as a drench or through irrigation systems
  • Protects root system preventing subsequent damage and plant loss, particularly for container-grown plants
  • Larvae treated with Nemasys L will not develop into adult vine weevils, eliminating unsightly damage to the foliage (typical leaf notching)

Why Nemasys® L?

Nemasys® L contains millions of beneficial nematodes of the Steinernema kraussei species and provides effective control of black vine weevil larvae. Nemasys® L is formulated to work at cold and warmer temperatures which range between 5°C - 30°C. Nemasys® L will control black vine weevil larvae whenever they are active in the soil. This is important when a vine weevil infestation is identified late in the autumn or early in the spring and a control strategy is required.

Beneficial nematodes are naturally-occurring microscopic worm-like organisms. Applied as a drench or through irrigation systems, they provide an effective, rapid and safe solution to control black vine weevil.

Product Profile

Active ingredient(s)Nematodes: species Steinernema kraussei
FormulationWater soluble gel (GW)
Pack size50 million or 250 million
CropsSoil or container grown crops including soft fruit and ornamentals
Pest activityVine weevil larvae (Otiorhynchus sulcatus)
Rate of applicationOpen soil: 1,000,000 nematodes per m2
Pots/containers: 500,000 nematodes per m2 Strawberry: 25,000 nematodes per plant
Application area treated: 50 million packOpen soil: 50 m2
Pots/containers: 100 m2
Strawberry: 2,000 plants
Application area treated: 250 million packOpen soil: 250 m2
Pots/containers: 500 m2
Strawberry: 10,000 plants
Water volumeOpen soil: 4.0 litres per m2
Pots/containers: 4.0 litres per m2
Strawberry: 100 ml per plant
Soil temperatureBetween 5°C and 30°C
Application MethodSoil drench (via boom sprayer, knapsack, lance or sprinklers)
Application adviceApply when larvae are present (lift a few plants/remove from pots to examine root ball – untreated larvae are white) Apply to plants in moist soil/growing medium, in sufficient water volume to ensure the root ball is thoroughly treated Avoid applications in direct sunlight, evening applications are best
Do not exceed 300 psi/20 bar/2000 kPa pump pressure
Nozzle aperture should be greater than 0.5 mm
Suitable nozzles should produce a course spray at the intended application pressure
Make up the stock solution and mix thoroughly to ensure that the nematodes are well dispersed
PrecautionsUpon receipt, use immediately or store in a refrigerator at 5°C
Do not use product if past expiry date or incorrectly stored (do not freeze)
Use entire packet at one time, do not store diluted product

How do Nematodes work?

  • Nemasys® L should be used to treat larvae of the vine weevils, which feed on the roots; the product is best applied when the larvae are relatively small. A second application may be required if more larvae subsequently hatch.
  • After application the nematodes attack the larvae by entering natural body openings or by penetrating the pest cuticle directly.
  • Once inside, they release bacteria that stop the larvae from feeding and which kill the larvae within a few days.
  • The nematodes reproduce inside the dead larvae and release a new generation of nematodes, which disperse to hunt down further larvae.
  • When nematodes can no longer find a host pest, they will die back to their original numbers. The more larvae there are, the better the nematodes perform.

 Technical Services Hotline +44 845 602 2553

Technical Services Hotline +44 845 602 2553

Technical Services Hotline

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