BASF Agricultural Solutions UK


Nemasys® is a biological control which effectively targets the larval stages of sciarid flies (also known as fungus gnats), western flower thrips and leafminers including Tuta absoluta in greenhouse horticulture production


  • Effective natural control
  • The potential for a high level of crop damage and reduction in crop value from sciarid and fungus gnat larvae, western flower thrips and leafminers is reduced
  • Eliminates the potential for chemical residues in food crops
  • Organic farming and IPM-compatible
  • No pest resistance issues
 Technical Services Hotline +44 845 602 2553

Technical Services Hotline +44 845 602 2553

Technical Services Hotline

Why Nemasys?

Product Profile:

Active ingredient(s)Steinernema feltiae (90%)
FormulationPaste (PA)
Pack size50 million or 250 million
Area treated50 - 200 m2 (50 million pack) 250 - 1000 m2 (250 million pack) Area treated depends on pest and rate of application For Tuta absoluta: 125 - 1,250 m2 depending on water volume (50 million pack) 625 - 6,250 m2 depending on water volume (250 million pack)
CropsGreenhouse horticulture
Pest activityLarval stages of sciarid flies (Bradysia spp.), western flower thrips (Frankliniella occidentalis) and leafminers including the Tomato leafminer (Tuta absoluta)
Rate of application250,000 – 1,000,000 nematodes per m2 For Tuta absoluta = 1,000,000 per litre = 400 million-4 billion per hectare at the recommended 400-4,000 litres per hectare water volume (see label)
Frequency of applicationAs required
Time of applicationDuring propagation and preventatively as required
Water volumeUp to 1 litre per m2 depending on pest (see label)
Aquatic buffer zoneNone

Why Nemasys®?

Nemasys® is a biological control product containing nematodes. It effectively targets:

  • The larval stages of sciarid flies (Bradysia spp.);
    - Feeding damage to young roots and the base of cuttings

  • Western flower thrips (Frankliniella occidentalis):
    - Silvery patches on leaves and flowers
    - Distortion of foliage and fruit
    - Reduced fruit set
    - Viral transmission eg necrotic spot virus (INSV) and tomato spotted wilt virus (TSWV)

  • Leafminers including Tuta absoluta
    - Larval mining of leaves, shoots and fruit which is unsightly and can reduce quality and result in downgrading of produce eg tomatoes

Nemasys® is compatible with IPM (Integrated Pest Management) systems and organic farming. Nemasys® persists for approximately 4 weeks in moist compost, thus protecting against newly emerging pests. There is no known resistance of the target pests to Nemasys®.

How to get the best from Nemasys®:

  • Apply when the substrate is between 10-30 oC
  • Use immediately on receipt of packs or refrigerate at 5oC (do not freeze)
  • Use within expiry date
  • Use the entire pack and do not store stock solution or diluted product
  • Make a stock solution as directed on the label, making a paste in the first instance and then adding remainder of the water, to avoid lumps forming; this solution should be mixed thoroughly to ensure nematodes are well dispersed and kept agitated
  • Application is as a foliar spray or drench to the growing medium via boom, lance or sprinklers, selecting the nozzle to give a medium (foliar) or coarse (drench) spray; the nozzle aperture should be greater than 0.5 mm, or via drip irrigation. A Dosatron unit can be used.
  • Remove all fine filters (50 mesh or smaller) from the application equipment
  • Partially fill tank with water, add stock solution, fill with water to the required level and maintain agitation
  • Do not exceed 300 psi/20 bar/2000 kPa pump pressure

Disclaimer: photo kindly provided by Ward Stepman