Slug

Slugs are common pests of many horticultural crops, particularly soil grown plants and in nursery stock where small water snails are of equal importance.

Type: Microscopic nematodes. 

How it works: Nematodes seek slugs and water snails, they enter the body and start to develop from infective juveniles to adults. In doing so a pellet of bacteria is released that begins to multiply spreading through the host body. Infected slugs are noticeable by the swollen mantle on their back, this ruptures a few days later releasing thousands of nematodes that seek to infect further hosts. 

Species controlled: Most slug species including Arion and Deroceras spp. and some snail species including those which are commonly found in nurseries.

When to use: Almost any time of year when soil temperatures are between 5 and 30°C. Soil moisture should not be a problem in commercial horticulture unless the area dries up completely. 

Rates of use: Apply as a drench using conventional equipment, i.e sprayer, dilutor, watering can or through most irrigation equipment. In all cases remove any fine filters and ensure water temperature is between 5 and 15°C.
  • Single application (6 weeks protection): 300,000 per m2. 30 million treats 100 m2, 250 million treats 833 m2. 
  • Short duration crops or high pest population: 150,000 per m2. 30 million treats 200 m2, 250 million treats 1667 m2. Apply every 2-6 weeks depending on the pest pressure. 2 or 3 applications are recommended. 
  • Outdoor crops with repeat applications: 50,000 per m2. 30 million treats 600 m2, 250 million treats 5000 m2. Apply every 2 to 4 weeks depending on pest pressure. A total of 3 applications are recommended. 

 
 
 Dead slug after infection (Photo: Becker Underwood)Swollen mantle on infected slug (left) and healthy slug (right)
(Photo: Holt Studios)