The explosion in the slug population predicted by wildlife experts earlier this year has been painfully evident in my garden, as the slimy critters have munched their way through beds, borders and container plants.

Venturing out each morning and evening on my constitutional slug patrol, I have picked off at least 30 of these incessant pests per session but each time I look out during or after a downpour, there they are again, climbing walls, scaling even the most thin-stemmed clematis, stripping plants of flowers and foliage and leaving their slimy trail.

There are more than 30 types of slug in the UK, some 95% of which are underground, nibbling on seeds and roots and laying 20-100 eggs multiple times every year.

It is believed that the average British garden contains over 20,000 slugs and snails. Slugs remain active in temperatures of 5C and above, consuming around 40 times their weight in the space of a day.

Warnings went out much earlier in the season predicting a slug population explosion, warning that young plants are particularly vulnerable to attack, but when slugs are on the rampage and in numbers as great as they have been this year due to the mild winter and wet summer, nothing is safe.

Paul Hetherington, director of fundraising and communications at the charity BugLife, says: "All the anecdotal evidence points to the sheer numbers of slugs and snails this year.

"They are bigger because they have not spent time in a torpid state of hibernation, they are reaching maturity earlier because they haven't had these periods of rest when their body mass reduces, and they breed whenever they are active, not seasonally.

"When it's hot and dry they will hibernate, but because of the weather, we have seen 11 months of slug and snail activity in the UK, whereas it used to be around seven."

The changing weather patterns - mild, wet winters and wet summers - have boosted slug populations, but the situation has been exacerbated by the loss of natural predators including hedgehogs, thrushes, frogs, toads and ground beetles, which feed on slugs and help retain the balance of nature, he says.

There are plants which slugs don't like, including aquilegias, geraniums and foxgloves, which have high toxin levels.

"I've found that they prefer courgettes to pumpkins - on my allotment they've eaten all the courgettes and left the pumpkins," he says.

Deterrents include copper tape around plant pots, placing sharp sand or crushed eggshells around plants, or even building a pond or water feature which will attract toads, frogs and newts, all natural predators to the slug.

Some people recommend boiling up cloves of garlic, straining off the liquid and watering around plants with that. Other than that, it's a case of continuing with dawn and dusk patrols to pick the slugs off.

While many people opt for slug pellets, Hetherington claims that even so-called organic varieties may harm other wildlife.

Guy Barter, RHS chief horticultural adviser, says nematodes are probably the most eco-friendly solution. Parasitic nematodes occur naturally in the soil, but not enough to see off the sheer numbers of pests. They can be bought from online garden retailers. The organisms are mixed with water and then watered into the ground. Some specifically target slugs, infecting them with bacteria.

"They are an excellent idea because they have no effect on non-targeted organisms, are safe for the user and are organic. The only downside is that they are rather expensive," Barter says.

However, Hetherington points to research that has shown cases of certain nematodes crossing species, infecting bees as well, so would recommend using them only as a last resort.

If, during your slug patrols, you come across any leopard slugs - so-called for their distinctive markings - it might be better to leave them alone, as they are carnivorous and will eat other slugs.

BEST OF THE BUNCH - Agapanthus

The African lily is a must-have perennial for sunny gardens, its large globes of blue or white flowers providing both colour and architectural value in borders and pots. Some of the brightest and biggest are least hardy, so go to a reputable supplier or specialist nursery who may be able to offer hardier and newer hybrids. After flowering, the heavy circular seedheads remain and are excellent for cutting and using in dried arrangements indoors. Agapanthus prefer sunny, sheltered spots and in pots they don't like to have too much space. In borders, however, don't let them be crowded in and shaded by other plants and make sure they're not too wet or cold in winter. Good varieties include Headbourne hybrids, which provide dazzling displays in late summer, or Agapanthus campanulatus, which are best for permanent border planting. Look for the deep blue 'Cobalt Blue' or A. 'Polar Ice', one of the best white forms.

GOOD ENOUGH TO EAT - Aubergines

They are a staple of the Mediterranean, in traditional vegetable dishes such as ratatouille or the Greek speciality, moussaka, but you can grow aubergines under cover or in the garden given warm, sheltered conditions. Sow indoors in early spring, two seeds to a pot and pinch out the weaker of the two if both appears. They need high temperatures and plenty of light to produce a good crop, so if you have a greenhouse, grow them in there and if not, keep them in a large pot in a sunny, sheltered pot on the patio, but don't put them out until June, when all danger of frost has passed. Pinch out the growing tip when the plant is 30cm tall to encourage more flowering sideshoots to form. Give them regular high potash liquid feeds and plenty of water when the fruits have set to boost your chances of success and support the main stems with canes. Plants grow to about 90cm (3ft) high outdoors and should yield up to 1.8kg (4lb) of fruit if you're lucky. Varieties worth trying include 'Black Enorma' and 'Moneymaker'.

WHAT TO DO THIS WEEK

:: Keep picking sweet peas to promote further blooms

:: Make earwig traps by filling a small plastic pot with dampened straw and placing it upside down on top of a cane at a similar height to the plants you want to protect

:: Lift and divide bearded irises

:: Keep deadheading bedding plants to keep displays looking their best

:: Remove the side buds of dahlias if you want bigger blooms

:: Plant autumn-flowering bulbs

:: Pick courgettes little and often, to stop them growing into large marrows

:: Protect carrots from carrot root fly by erecting a 60cm-tall fleece and cane fence around crops

:: Harvest damsons and plums

:: Lift onions once their foliage has turned yellow and leave them in an airy space to dry out

:: In the greenhouse, water and mist your cuttings