5 COMMON PESTS

Slugs and snails love succulents such as hostas and emerging delphinium shoots. Solution Copper collars placed around the plants as the shoots emerge from the ground are the most effective. Enrich the earth with organic matter to encourage faster, more vigorous growth. Hand-pick them off the plants after dark.

Aphids such as greenfly and blackfly suck sap, weaken plants and spread viruses. The sticky honeydew they produce encourages sooty mould. Solution Encourage birds that will feed on aphids. Wasps, lacewings and hoverflies also help, so grow plants that attract these beneficial insects. Dislodge heavy infestations by rubbing them between your finger and thumb or squirting with a hosepipe.

Whitefly colonise the undersides of plants leaves, especially tomatoes, weakening them and secreting honeydew. Solution Plant French marigolds (tagetes) in the same soil as the tomatoes. The pungent exudate given off by the marigolds seems to be effective at discouraging attack. Biological control is available and sticky yellow plastic sheets will trap the pests.

Carrot fly larvae burrow into the roots of carrots and weaken them, as well as making them unappetising. Solution Sow the seeds thinly so that subsequent thinning is unnecessary. When carrot seedlings are thinned out, the aroma released attracts the flies. Cover carrots with fine crop-protection netting that will exclude the pest.

Cabbage caterpillars are laid by large and small white butterflies. They eat the foliage and leave behind nasty black frass (poo!)

Solution Cover the plants with crop protection netting to prevent the butterflies laying eggs. It is a wider mesh than the netting used to repel carrot fly.