© Alamy

1 Box tree caterpillar

The grubs cover plants in webbing. Pick them off, use a pheromone trap or nematodes, or try a chemical such as Bug Clear Gun, Defenders Bug Killer or a chemical from Provado or Westland Resolva.

© RHS/Andrew Halstead

2 Fuchsia gall mite

Causes galls and distortion, and is resistant to most chemicals. Remove, burn or bury infected shoots. Fuchsias with some resistance include ‘Baby Chang’, ‘Space Shuttle’, and F. thymifolia.

© Alamy

3 Viburnum beetle

Chews holes in foliage, though plants survive. Grubs are often too numerous to pick off ,so treat when they emerge (April-May) with pesticide (Bug Clear Gun for Fruit or Sprayday Greenfly Killer).

© Alamy

4 Tortrix moth

There are almost 40 species and the caterpillars bind leaves together with silky threads to shelter and feed inside. Crush the grubs, use pheromone traps or a chemical such as Py Bug Killer.

© Alamy

5 Glasshouse mealy bug

Fluffy sap feeders that excrete honeydew, causing sooty mould to form on foliage. Biological controls can be used from May-September indoors and undercover, or try an organic pesticide.

© Alamy

6 Pear blister mite

Causes blistered foliage in spring, which eventually blackens. Infestations are unsightly rather than fatal to the plant, so remove a few infested tips, but not too many. There is no chemical control.

© Alamy

7 Woolly aphid

A common pest that appears as a fluffy, waxy mass. Scrub with a stiff brush and encourage ladybirds, lacewings and hoverflies, which are natural predators. Use an organic chemical on large populations.

© Alamy

8 Alder leaf beetle

Thought to be extinct in the UK 1946-2003, larvae were found in Manchester in 2004. This pest is impossible to contain, but won’t kill trees. Pesticides work better on grubs than adults.

How to garden well without using chemicals

Going organic is a great way to garden, but it takes a lot of time and effort to do it properly.

However, even if you can’t do away with chemicals altogether, you can reduce their use by keeping plants healthy and encouraging predatory insects into the garden.

Healthy plants are stronger and more robust, and are therefore less susceptible to pests and more able to withstand any attacks.

Make sure your plants are fed and watered regularly, and have plenty of air circulating around them.

Many insects, including ground beetles, ladybirds, hoverflies and lacewing flies, predate aphids and other pests, so make them welcome.

Hedgehogs, amphibians, slow worms and birds will also tuck into pests, including slugs and snails.

Some snail deterrents such as wool pellets also double as a useful mulch to help improve the soil around plants.