Nemasys® L Beneficial Nematodes

Nemasys L Steinernema kraussei beneficial nematodes help provide biological control of black vine weevil.

Nemasys L is based on the beneficial nematode Steinernema kraussei and provides a rapid curative control of black vine weevil. Nemasys L has the added advantage of being cold-temperature tolerant. Nemasys L will control black vine weevil larvae in soil temperatures down to 41°F. This means it will infect and kill black vine weevil larvae whenever they are active in the soil.

Nemasys L contains nematodes in their vigorously infective juvenile stage. These aggressive organisms actively seek out black vine weevil larvae and enter them through their natural openings. Once inside the larvae, they release symbiotic bacteria, quickly killing the insect pest. The nematodes then reproduce inside the insect and release a new generation of infective juveniles, which disperse in search of further larvae.

Nemasys L is a very robust nematode and can withstand higher environmental pressures than other nematode species; this makes it the product of choice when controlling black vine weevil in field and testing conditions.

Beneficial nematodes are microscopic worms that attack and kill targeted insects, without affecting any other organisms. Within the infected insect, the beneficial nematodes continually reproduce and then spread out for long-term control.


  • Effective against larvae at warm and low soil temperatures (41°F to 86°F)
  • Wide application window (early February to late November) whenever the larvae are active
  • Very robust, long persistence and survival in testing conditions
  • Active for up to 6 weeks after application
  • Infected larvae turn dark yellow

See our product instruction sheet for suggested application rates under our research library.

Package sizes include trays of 50 million and 250 million nematodes.

Always read and follow label directions.

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