Slug Identification
 

UK Slug Varieties

(click on an image to enlarge it)


Ashy-Grey Slug (Limax cinereoniger)
The largest UK slug which can reach up to 25cm when fully grown. Body is an ash-grey colour with a pale yellow keel along its back from head to tail. It occurs through out the UK but is normally restricted to mature and undisturbed woodlands and so not a real threat to crops.


Common Garden Slug (Arion distinctus / Arion hortensis)
This is a relatively small slug tending to be around 3cm long when mature. Its is common in the north of England, lowlands of Scotland and parts of Ireland. The body is brown in colour, striped lengthwise and covered in tiny gold spots. Its underside is orange and it has orange body mucus. It is common on agricultural land and can do serious damage to crops.


 

Common Keeled Slug (Tandonia budapestensis)
This is the most common of the keeled slugs. It is relatively small reaching around 6cm at maturity. It is typically black or grey in colour with a yellow-orange ridge along its length. It remains mostly underground and will feed on newly drilled seeds which will have a serious effect on emergence. If populations are large it can lead to the need to re-seed.


Dusky Slug (Arion subfuscus)
This is a moderate slized slug, reaching up to 7cm at maturity, which is common in most parts of the UK. It favours woodlands, hedgerows and can also be found in gardens and allotments. The body is a pale shade of brown but with darker lengthwise strips. It can look more golden in colour due to orange body mucus. It has a yellow sole and sole mucus is colourless.


Large Red Slug and Black Slug (Arion ater)
This is widespread and common throughout the UK in most terrestrial habitats. It can reach up to 12cm in length. Body is uniform in colour but can be either orange-red or black. When alarmed it contracts into a spherical shape and may rock from side to side. Mucus is colourless. This slug is rarely a problem in arable crops.


Lemon Slug (Limax tenellus)
This is a small (max 4cm), bright yellow slug which has dark tentacles. It is scarce and almost always found in woodland. It is a good indicator of ancient sites. Feeds on fungi. Very low risk to agricultural crops. 


Leopard Slug (Limax maximus)
This is a large slug - up to 16cm in length - which has distinctive black leopard like marking on its upper body. Its underside is white. It has a pronounced keel along the rear of its body. Mucus is sticky and colourless. Widespread and common in the UK favouring woodland and gardens. Low risk to agricultural crops.


Netted or Grey Field Slug (Deroceras reticulatum)
This is a common slug of gardens and agricultural land and is widespread throughout the UK. It is relatively small between 3 and 5cm in length. The body colour varies but is normally light brown with a network of darker veins and blotches. The keel is truncated at the tail and the body can look lumpy. The mucus is colourless and produced in large quantities especially when disturbed. This slug will feed on seeds and above ground on plant leaves and so is a serious threat to crops. It will feed even in freezing temperatures.


Shelled Slug (Testacella scutulum)
This is a strange slug which has a finger-like shell covering its rear end. It  can reach up to 10cm long at maturity. Its body is a pale orange in colour. It spends most of its life under the soil surface. It is a predator of earthworms and so unwelcome on agricultural land. 


Tree Slug (Limax marginatus)
This is a pale, translucent slug which can grow up to 7cm in length. The body colour is pale grey and is marked by two dark lines on both sides of the body. As its name suggests it is found mostly in woodland climbing trees especially in wet weather. Its mucus is colourless and watery which is produced in large amounts when disturbed.


 

Yellow Slug (Limax flavus)
This is a large yellowish slug which can grow up to 10cm in length. The body is marbled and mottled in an olive colour. Its tentacles are blue. It is common and widespread in England, Wales and Ireland. It is mostly associated with houses and gardens - being known to venture indoors especially cellars after dark. Feeds voraciously on seedlings and vegetables so where it does occur on agriculture and horticulture land it can do serious damage.


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