Tackle aphids in the greenhouse

Tackle aphids in the greenhouse before they get to plague proportions and do some serious damage to your plants.

Once upon a time, a gardener could reasonably rely on the weather to kill off any aphids lurking in the greenhouse during winter. Not any more though. Rising temperatures mean they're emerging in spring unscathed, and with reinforcements – so you'll need to be on your guard from the word go.

Whatever you grow in your greenhouse, from edibles like sweet peppers and tomatoes to summer bedding seedlings, geraniums or even orchids, they're all martyrs to aphids. You'll find their soft green bodies clustered on the undersides of leaves, particularly near shoot tips where they suck sap and excrete honeydew attracting secondary infections of black sooty mould. They also transmit viruses, so always tackle the problem straight away.

A small infestation can be picked off and squashed – though you'll need to patrol every day. If you really get overrun, insecticidal soft soap sprays, available at our garden centre in Co. Limerick, can be very effective. And remember to encourage natural predators into the greenhouse by opening up windows and doors wherever possible and sowing brightly-coloured annual flowers such as nasturtiums and marigolds - it looks pretty, too!