Recognising a Slug Infestation
Slugs come in many varieties and there is a good chance that several different kinds of slugs roam through your garden. Most slugs feed at night. You may see them early in the morning or by the evidence they leave behind. They leave behind trails of translucent white slime as they work through the garden. If you see these slime trails near damaged plants, then you probably have slugs.
Not all slugs feed above ground. Many burrow through loose soil and feed off roots and tubers. Potatoes are particularly vulnerable and will show their damage with small grey holes in their skin, usually about a centimetre wide.
Some varieties of slugs are able to climb up stems and reach leaves. Any tender leaves are vulnerable but vegetables seem to take the worst damage. What is food for people is food for slugs too.
Leaf damage from slugs usually appears as circular damage or holes in the leaves. Often the slug trails are still evident on the remaining leaf.
Protecting Your Garden
Slugs can be deterred with natural barriers placed around your plants. The slug’s bottom side is very soft and slippery. Anything gritty or sharp can be used as a barrier, so long as one takes care to regard pets and wildlife.
Eggshells are a cheap and environmentally responsible barrier for slugs. Break them into very small pieces and use the pieces to make lines around your garden. The slugs will not be able to cross the lines and over time the shells will break down and add nutrients to your soil. Sand, soot or gravel may also be used effectively. These lines will have to be maintained continually as they are eroded by wind and rain.
Some gardeners will build small fences from strips of plastic that are about twenty-five centimetres high and pushed into the ground. Although this may be effective against slugs, the plastic is unattractive and the resulting shade may be counterproductive to the garden.
Another alternative is to place copper strips or plates; they give slugs an electric shock when they come into contact with them so can be placed around plants or underneath plant pots.
Slugs may also be lured away from your garden and into traps. Traps are made by sinking containers every meter or so around your garden. The mouth of the container should be exposed about two centimetres above the ground. Small amounts of beer are placed in the bottoms of these traps. Slugs will fall into the containers and drown as they try to reach the beer. This method has some drawbacks. The beer must be replenished often and you may find small pets have started spending more time in the garden.
The introduction of natural predators is another effective way to combat slugs. Garden stores can provide nematodes that are watered into the soil where they consume slugs and eggs. Frogs, birds and hedgehogs will all feed on slugs. Keeping cats out of the garden and providing a water source for these animals will encourage them to forage in the area.
Insecticides are available to kill slugs. Metaldehyde pellets like Insecto Slug Pellets are effective when spread around seedlings but are also poisonous to other animals and should be used with great care. Non-toxic gels can be purchased and this is a far safer route where children, pets and wildlife are concerned.
Keeping a garden tidy and well maintained will often prevent slugs from overtaking your efforts. Regular tilling or digging thought the soil will disturb any eggs and bring slugs to the surface where they can be seen by predators.
Removing stacks of wood, plastics or flower pots will reduce the moist protected areas where slugs thrive. Any time you find a surface that is covered in slime trails you should investigate it as a breeding area for slugs.
Slugs come out at night. Many slugs can be eliminated simply by walking through the garden at dawn and removing them. Dispose of them in a bucket of water or move them to another location that is far from the garden.
As an extra measure, choose crops that are bred for their resistance to slug damage. Many garden vegetable seeds, particularly potatoes, are available in slug resistant varieties.
No single method of slug control will be entirely effective. The best way to combat slugs is to incorporate a variety of control techniques into your gardening habits.