Pesticides & Weedkillers

Aphids are extremely common but can significantly impact on plant growth. There are hundreds of species, but the most commonly known can be grouped as greenfly or blackfly – although equally may be orange, brown, or pink in colour. You may spot them clustered on the stem of soft shoots – look under leaves in particular – or may find a sticky substance on your plants that gives away aphids have been there sucking at the sap.

Look for leaves that are curling, yellowing, or misshapen. The presence of Honeydew (a clear, sticky substance, often accompanied by a black sooty coating) is another good indicator of aphids.

Aphids eat a huge variety of plants, both outdoor, and in the greenhouse. They prefer soft, new shoots.

A number of beneficial insects, including ladybirds, lacewing larvae and hoverflies, are natural predators of aphids so a good garden ecosystem will help with control. If there are not too many, you can also squash them. If your plant has a real infestation, gently shake the plant so the aphids fall off. Chemical killers such as Resolva Bug Killer are also effective.

These small white-winged insects, at just 1 or 2 mm in length, look very much like white moths as adults and are related to aphids. You may well spot them on the underside of leaves; they prefer younger, fresher leaves and they will fly in clusters when you disturb them. Their lifecycle is only three weeks long, which means an infestation can occur very rapidly.

Whiteflies cause damage by sucking the sap from plants. This may not be immediately visible – you are more likely to spot the insects themselves – but a large infestation can lead to a black sooty ‘mould’ like appearance on leaves, which weakens plant growth. They are particularly prevalent in greenhouses.

They can be found on a wide range of plants, including azaleas, rhododendrons, honeysuckle, plus edibles including cabbages, tomatoes and cucumbers.

In greenhouses, you can catch adult whiteflies by hanging yellow sticky traps. You can also try companion planting as a form of deterrent; the strong smell of marigolds for example is a deterrent, so these are often grown next to vegetables or in a greenhouse. Chemical killers such as Resolva Bug Killer are also effective.

Ragged leaves with holes in them, scalloped bites / nibbles at the edges of leaves. You are likely to be able to spot silvery slime traces near the damaged plant, or on it. Slugs attack at night so look for fresh damage first thing in the morning. Most plant damage is done by small slugs and snails that go unnoticed.

These voracious molluscs consume almost anything, but particularly love tender leaves along with vegetable, fruit, and salad crops.

Encourage slugs’ natural enemies into your garden; slow worms, hedgehogs and centipedes. Placing copper coins around plants, can also meet with success. Failing that, try control methods such as Slug Gone Wool Pellets or Slugs Be Gone Defence Gel.

Definitely not the only caterpillar species to wish to chomp on your vegetables, cabbage moth caterpillars are particularly destructive as they will happily make their way into the heart of the brassica.

You can see where they have been by the holes in the leaves of your brassicas. You may physically spot the caterpillars.

Create a garden ecosystem that includes natural predators – birds in particular will eat them. It is also possible to pick off the caterpillars and any eggs regularly by hand. You can try and use marigolds as a companion plant that repels the cabbage white butterfly (don’t plant marigolds too close though, as they can reduce the root growth of the cabbage).

The black vine weevil, is a black-brown, moderately sized insect at around 1cm in length. It has a beetle-like appearance, with fused wings meaning they cannot fly, and orange hair tufts on their wing cases.

Black vine weevil larvae are c-shaped, have no legs, and are white with copper coloured heads.

They are particularly keen on plants in containers, such as heucheras and hostas.