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B-green | Chafer grub nematodes

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  • Combats various types of chafer grubs
  • Best time to apply is August - September
  • Use at a soil temperature of at least 12°C
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    B-green contains nematodes to control both chafer grubs and black vine weevil larvae. Chafer grubs feed on grass roots, while the larvae of the vine weevil feed on the roots of many species of ornamental plants, vines, strawberry plants, etc. This weakens and eventually kills plants.

    Chafer damage

    Grubs feed on the roots of the lawn, causing it to die. Initially, dry, yellow, brown and open spots appear on the lawn. If you fertilize the lawn well and irrigate it sufficiently, the grass will hold up and you will not see the actual damage until after a period of drought.

    The clumps of grass will come off over time, you can basically roll up your grass, and underneath it, you will easily see the grubs. If there are no more roots available, the grubs will move to healthier grassy areas. So it is important to treat the entire lawn with nematodes or at least around the affected areas well, to prevent the spread.

    Birds and moles, which are fond of grubs, will arrive in your lawn to eat them, which aggravates the damage even further.

    Fighting grubs

    Grubs can easily be controlled with nematodes.

    B-green contains nematodes that work against grubs and vine weevil larvae. After spreading B-green on the affected lawn, the nematodes seek out the larvae and enter through the natural openings in their bodies. Once inside the larva, the nematodes will excrete bacteria that cause the death of the larva. This causes a white/beige to reddish brown coloration of the larvae.

    The first larvae die already two days after the treatment. In the dead larvae, new generations of nematodes will appear, which in turn will look for larvae. The product remains active for six weeks. After these six weeks, the nematodes will die due to soil mold and other naturally occurring nematodes.

    B-green consists of Heterorhabditis bacteriophora nematodes. These nematodes are safe for humans, animals (including earthworms) and the environment. There are no resistance problems.

    Application period

    The best time to apply B-Green is in August - September. All beetles have laid their eggs shortly before this time, so there will be small larvae present of any of the common chafer species. The soil temperature is warm at this time, and it is usually not too dry, which also makes it an ideal time to apply nematodes.

    It may also be prudent to treat in the springtime as well, depending upon which species you have in your lawn. Certain beetles also lay eggs in the spring as well as in the late summer. See more about this below.

    Application period per beetle species

    • The garden chafer Phyllopertha horticola can be treated from mid-July to mid-October, and from mid-April to the end of April if the spring is warm (the soil temperature must be 12°C for 2 weeks).
    • The rose chafer Hoplia philantus can be treated from the end of April to the end of September.
    • May beetles and June beetles Phyllophaga spp.: Only the young larvae that have just hatched can be treated with B-green from the beginning of mid-August until the end of September. For treating larger grubs that have overwintered, use B-Green+ in the spring (April through June).
    • The black vine weevil Otiorhynchus sulcatus can be treated from mid-July to the end of September. In the spring (mid-April), you should use Kraunema nematodes to fight the vine weevil. Kraunema nematodes are more tolerant of cold temperatures and can be used much earlier than B-Green.

    Dosage of B-green

    For chafer grubs, the dosage is the same as for the black vine weevil. We offer nematodes for treating 10m², 100m², 500m² or 1.000m².


    Overdosing with nematodes is impossible and will only have a positive influence on the result. The more nematodes are present in the soil, the sooner all grubs will be infected and the sooner your lawn will be free of them.


    Biogrowi is a pioneer in bringing effective, pesticide-free biocontrol to the consumer market in western Europe. We have more than 30 years of experience. If you have any questions, please feel free to contact us. We will be happy to help you!

    Pro's & cons
    • plus-circle Effective against various types of chafer grubs
    • plus-circle No residue, run-off or resistance
    • plus-circle Harmless for children and pets: no waiting time after application before you can walk on the lawn
    • minus-circle The lawn must be watered well for 2 weeks
    • minus-circle Cannot be applied on a sunny day
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    Need help?
    We are available from 9 a.m. to 5 p.m. CET, Monday through Friday. We speak English, Dutch, French and German!
    Contact us