Vine weevil control

The Pest

The Black Vine Weevil (Otiorhynchus sulcatus) is a pest of many crops, and is a major pest where polythene or containers are used.  Adults are 8-12mm long and dull black in colour with patches of tiny yellow bristles.  The C-shaped larvae are 10-14mm long, very bristly, cream in colour with a shiny brown head and no legs.
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Biological Controls

» NEMASYS® L Steinernema kraussei in units of 50 and 250 million
» NEMASYS® H Heterorhabditis megidis in units of 50 and 250 million 

Nemasys® H and Nemasys® L are registered trade marks of Becker Underwood.

Nemasys® L

Nemasys® L contains the UK strain of the insect parasitic nematode Steinernema kraussei.  Applied to the compost as a drench, the nematodes seek out the vine weevil larvae, enter into their body and release a symbiotic bacteria which kills the pest. The dead larvae turns a darker yellow.  The nematodes reproduce inside the dead larva as it decomposes and then a new generation of infective juveniles move off to seek out further larvae to invade.

Nemasys® L works best with temperatures above 5°C and is killed below 0°C. Soil should also be moist at the time of application, if necessary irrigate beforehand.  It is a sensible precaution to apply in the evening or on a cloudy day to reduce the effects of UV radiation and drying out.  In outdoor crops treatment is usually possible to treat from late February to early November.   Late autumn is the best treatment timing (late October) after all the eggs have been laid.  A second treatment in March is advised where there are high populations.

Nemasys® L is a registered trade mark of Becker Underwood.

Directions for Use

Nemasys® H

Nemasys® H contains the UK strain of the insect parasitic nematode Heterorhabditis megidis.  Applied to the compost as a drench, the nematodes seek out the vine weevil larvae and enter through natural body openings or by penetrating the vine weevil larva cuticle. A symbiotic bacteria is then released which rapidly kills the vine weevil larva. Within three weeks of application the majority of larvae will have been parasitised (often turn a reddish-brown) and killed.  The nematodes reproduce inside the dead larva as it decomposes and then a new generation of infective juveniles move off to seek out further larvae to invade. Nemasys® H is an aggressive nematode which, under ideal conditions, is highly active after application to give a rapid control of high pest populations.

Nemasys® H works best with temperatures above 12°C. Below 10°C and above 30°C the nematodes become inactive. Soil should also be moist at the time of application, if necessary irrigate beforehand.  It is a sensible precaution to apply in the evening or on a cloudy day to reduce the effects of UV radiation and drying out.  In outdoor crops treatment is usually possible twice a year, mid April to mid May and mid August to mid October.  Crops grown in polythene tunnels may be treated earlier and later than this the soil temperature is sufficient. Nemasys® H is better suited to container growing systems where there is less environmental variation.

Nemasys® H is a registered trade mark of Becker Underwood.

Directions for Use

Which nematode species to choose?

All nematodes require a moist soil environment for optimal activity and efficacy, however, Nemasys® H is more susceptible to desiccation whereas Nemasys® L is relatively drought tolerant.  Nemasys® L is a more persistent nematode giving high levels of control whilst active in the soil environment for longer periods of time post-application.

When field conditions are optimal, both species give similar high levels of control, but Nemasys® L has increased efficacy and persistence under the range of field and contained conditions.

Nemasys® H and Nemasys® L are registered trade marks of Becker Underwood.