Pest Control
Slugs Problems
The GardenAdvice guide to controlling slugs and snails in your garden.
There are 24 different species of slug in Britain, about half of which can be found in the garden. Most slugs eat decaying vegetation, but readily switch to young or delicate plants, feeding on the leaves, stems, roots and tubers. They evolved from snails and in the course of doing so lost all, or most of their shell. All slugs are hermaphrodite, that are they have both male and female sex organs. Mating and cross-fertilisation is the norm, but every individual produces the spherical translucent eggs. These are laid in batches in damp places in the soil or under stones. A small replica of the adult emerges from the egg, and takes between 2 months and a year to mature. The activity of slugs and snails is highest in the spring and autumn. Slugs need to keep moist at all times otherwise they will dehydrate and die: thus they are nocturnal, and more active when it is wet.
GardenAdvice.co.uk 6 steps to slug control in your garden
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soil conditions
Slugs need spaces to move through the soil; creating a good fine tilth will discourages them. Moving the soil surface with a rake in winter will expose many slugs and their eggs to frost damage.
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hygenic practise
Remove fallen and damaged leafs from your tender plants remember slugs eat decaying vegetation, so remove this source of food.
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Encourage predators
Ground and rove beetles, centipedes, frogs and toads, slow-worms, hedgehogs and many species of birds all eat significant numbers of slugs. To encourage frogs and toads maintain a pond (without goldfish) and for slow-worms keep some long grass and avoid using a strimmer.
The Hedgehog Method:
Hedgehogs are predators of slugs so you need to attract them into the garden. At night time lay out dog food, which they love to eat - don't use bread or milk because it's bad for them. Once we've got them into the garden we need to keep them, so provide them with a water-proof box, about 18 inches long and 12 inches deep, fill it with straw so it's nice and snug, make it waterproof and hide it by covering it with leaves. Then the hedgehog can live in there. You'll not only get rid of pests, but, if you have children, they'll be delighted.
The Trench Method:
To encourage ground and rover beetles. Dig a trench about six inches deep and three inches across, and then line it with pebbles and Perspex edges. Beetles, which are a predator of slugs, will fall into the trench and can hide under the pebbles, which will protect them from birds. When the slug falls in, the beetle will have his dinner.
Parasitic nematodes
(Phasmarhabditis hermaphrodita) are available from Defenders Limited (01233 813121). These must be applied to the soil in solution. Be sure to follow the pack instructions. Treatment should be done in a block and the soil temperature must be above 5 degrees C.
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Barrier methods:
Various materials or uncomfortable for slugs and snails to cross and a barrier provides some protection for vulnerable and valuable plants.
Vermiculite
Vermiculite, which is normally a compost addition, and this is an interesting product because as it swells up with water - and we all know slugs love water - it actually moves which the slugs dislike. We've found vermiculite to be 90% effective as a control; we put it around the base of a plant in a ring. It's particularly good for plants that love water.
Gravel
The only gravel that works as a barrier is the crushed form because it has very sharp edges our favour is horticultural grit 4 -8 mm.
Bark
Bark has a downside that in wet weather it can help the slugs travel to your plants. However in a dry season using a coarse bark made from large pieces is difficult for the slugs to move through because it becomes very dry.
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Hand picking and trapping:
slugs can be collected at night with a torch. Traps can concentrate slugs to specific areas for picking. Traps made from glossy magazines, but old bits of carpet or old plastic plant trays make more effective slug traps. These provide a damp place to rest during the day and slugs can be removed in daylight. Such traps also provide refuge for ground beetles and centipedes that feed on slugs and their eggs. Using suicide plants to bring the slugs out of the soil for collection before you plant or sow your crop can also help to reduce numbers and restrict damage
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Trapping
If you need results quickly trapping is the method to opt for.
The Beer Trap Method:
This is quite a traditional technique. All you need is a jar, put it on its side with a small amount of alcoholic beverage in it, and when slugs come along they'll drown in it. It's very simple, it's effective, and you don't need the whole can either.
Black plastic bag method
If you have a slug attack in one area in your garden this is a quick method to reduce the numbers. Take one black bin liner place on the ground in between your tender plants, then place two lettuce which are well pass there sales date. Finally add two tea cups of breakfast bran and pour a cup full of beer (bitter is best) over the lettuce. Leave over night with the top open and check in the morning, the slug should have climbed into the bag over night and as the sun raises in the morning taken shelter in the bottom of the bag, ready to be removed from your garden.
Slug X
This is a slug trap that has been developed over a two-year period, using trials with cardboard boxes before the final plastic prototype was manufactured. The gardenAdvice team presently have these traps under trial. More details can be found at www.westfield-products.co.uk
And finally, if you have both the space and the right environment then ducks and chickens are dual-purpose domestic animals that are great slug and snail hunters.
Moles
If you have ever had problems with moles you will be aware just how hard it is to control them. Arriving from almost thin air you wake up one morning to mole hills. It only takes a couple of days to turn your perfect lawn into a scene from the "battle of the Sohm". The gardenadvice team are often asked to advise on mole problems, this article is a summary of the advice.
Earthworms attract moles. Lawns are an ideal hunting ground the worms are near to the surface and the network of grass roots supports extensive tunnelling. Establishing a centre the mole or moles will work out digging several feeder tunnels. Once the basic network has been formed they sit back and wait. With an excellent scenic of smell and hearing they can detect a worm up to 5 metres away. As the worms work through the soil they drop into the moles tunnel and become another tasty meal.
Traditional solutions have included the control of the earthworms mainly because of the worm casts they create. However earthworms do a lot of good improving drainage, breaking down organic matter in the soil and help support health topsoil. By removing or controlling the worms you will control the moles however the price is high, as you will damage your soil.
Trapping is often the best method for young inexperienced moles. The normal type of trap has a scissors action which to be honest is somewhat barbaric. Working by being placed in the main run the mole trips the trap and kills itself. The key to trapping is to set the trap without introducing any foreign scents or smells. To achieve this use old traps or buy new traps and bury them for a few weeks. Secondarily before you touch the traps or the mole run covers your hands in soil to hide your own scent. The traps should then be placed in the moles runs so that the trap sits just above the run base. Once the trap is set make sure that no light can get into the mole run by adding turf or soil around the top of the trap. It all sounds very simple but the truth unless you are setting traps every day an have considerable experience you will more than likely fail. Its amazing to see your carefully set traps dug around, set off and them thrown out of the ground or just plain agrored. Once a mole as seen one trap and survived you can forget about using this method again, the mole seems never to forget.
Fumigating is another method often used, which involves finding the run then using a special mole smoke to fumigate the run. On the whole this is an effective method, however you are limited to how far the poisonous smoke will travel and also the moles can dig there way out of trouble. The smokes contain sulphur and can only be used when the weather is warm as in cold damp weather the smoke will not travel in the runs.
Baiting worms with poison is another method, which can be used. This is best carried our by a professional mole catcher as the poisons used are licensed and very dangerous to other animals and birds.
The Garden Advice preferable method is to move the moles on into a more suitable area such as a meadow or out of the garden. This avoids embarrassment on our part as the moles inevitably show us up when we employ the other methods detailed earlier. We achieve this by using jeyes fluid which is a chemical that has been used for gardeners for over 50 years for a whole range of tasks including sterilising pots and soil, controlling moss and a whole host of other uses. We simply find the run open the highest end up and using a watering can pour in a strong mix of jeyes fluid and water (1 ; 20 ) With the mole having a highly developed sense of smell it tends to drive them away from there current location. To make sure they are going in the right direction we also water a banned across the lawn or bed (using a diluted mix 1:40) to form a barrier against the mole moving in an undesired direction. Over about 10 days we continue this operation until the move has moved on or at least into a less damaging area.
Vine Weevil
The symptoms
Vine weevil is a secretive insect, not often seen during daylight hours. The adult hides away during the day - sheltering under leaves and in cracks and crevices in walls and fences. The adult, larval and pupa stages are under the ground and out of view.
Step one:
Despite plants being well watered and cared for diagnosis of vine weevil in the garden or house tends to start with seemingly inexplicable yellowing and wilting of your plant foliage.
Step two:
Closer examination often reveals notching around the outer edges of foliage caused by the adults feeding at night.
Step three:
Knock the plant out of the container and examine the root ball. The larvae of the vine weevil are easy to spot, white, legless maggots about 10-12 mm long with a brown head present in the soil or compost. The weevils feed on the effected plants roots to such an extent that it kills it.
Control
Collect adults by touch light by hand at night then the adults are most active. Removal of the maggots from the root ball by knocking out the plants and inspecting the roots.
Biological Control
Treatments against vine weevil based on biological control agents such as nematodes can be effective. Typically the main drawback with this technique is that the vine weevil larvae are damagingly active at temperatures much lower than those required for effective control by the nematode worms.
Nevertheless, this technique can be useful under protection, where temperatures are higher.
Insecticides for ornamental plants
This is the simplest solution for garden shrubs. The insecticide must be of the systemic type so that it enters the plant and enters the roots killing the vine weevil maggots directly.
Plant protection compost
Until the launch last year of Levington Plant Protection Composts, there was no insecticide available to amateurs that would protect plants from root damage by the larvae of Black Vine Weevil. This unique compost is the new 'anti vine weevil' compost, which has been treated at manufacture with the insecticide Intercept (imidacloprid). This insecticide works by systemic action to give control of the soil dwelling insect pests, vine weevil and sciarid fly for up to one year and is taken up in the plant to control sap-sucking foliage pests green fly and black fly for up to 3 months. It has also been shown to give useful control of whitefly.
Pot on seedlings and baby plants in Levington Plant Protection compost. As the plants get bigger re-pot into more Plant Protection Compost. Make sure only Levington Plant Protection Compost is used in the container because the Intercept insecticide cannot 'flow' from treated compost into untreated root ball. Any larvae in, for example, the root ball of a plant being potted on will not be controlled and may still kill the plant by eating all the roots. With plants already infested, the best advice is to wash the roots clean of old compost before re-potting into Levington Plant Protection Compost.
There are three varieties of Plant Protection Compost:
- One for Outdoor Containers
- One for Houseplant Containers
- And one for Ericaceous Containers
Grow 'trap plants'
The idea is to grow plants such as primula, polyanthus, cyclamen etc that are attractive to Vine Weevil adults in pots of Levington Plant Protection Compost. These plants are placed amongst garden plants that are vulnerable or have been attacked. The adult will go for these trap plants, lay their eggs in the Lexington Plant Protection Compost and the next generation is controlled completely. |
