Q: My chilli plants have aphids and I’m not sure what to do to safely get rid of them. Any advice? NL, Co Laois
A: Aphids – an umbrella term used for many different types of small sap-sucking insects including greenfly and blackfly – are a common sight on the soft, growing tips of many different kinds of plants in summer. Generally found in very dense clusters, they feed on plant sap and produce a sticky substance known as honeydew that many other insects including bees and ants like to eat. The aphids themselves are also an important food source for other garden wildlife, including ladybirds, ground beetles, hoverflies, parasitic wasps and birds, so are a part of your garden’s natural biodiversity. Their numbers are best controlled by leaving them alone for their natural predators to consume, an important process that’s part of the complex cycle of the seasons in any organically-managed garden.
That said, aphids can spread plant diseases and are unsightly and unsavoury on a homegrown food crop like chillies, so I can fully appreciate your predicament. For this reason, I’d suggest using a fine spray of water from a garden “mister”, water pistol, or handheld spray-gun to wash them off your plants. This should do the trick but if the problem persists, then you could try using a traditional soap-based remedy such as Uncle Tom’s Natural Soft Soap (available from fruithillfarm.com), which is regarded by most organic gardeners as environmentally acceptable.
This non-residual, biodegradable treatment works by direct contact only (its active ingredient is the soft soap that works by washing away the insects’ protective cuticles and then clogging up the spiracles they use to breathe) but should still only be used as a last resort to avoid the risk of potential harm to other insects.
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Also bear in mind that aphid infestation can sometimes be a sign of plant stress, indicating that its growing conditions are less than ideal. In the case of chilli pepper plants, this tender, heat-loving species needs a very warm, sheltered, humid position in full sun with protection from cool winds and heavy rainfall, which is why it’s generally best grown under cover in our cool, damp Irish climate in a glasshouse, polytunnel or warm, sunny windowsill. Temperatures between 15 and 30 degrees suit it best, along with a watering regime of “little but often”.
Once the plants start to flower, a regular potash-rich liquid seaweed feed will also boost health and productivity, and help protect them from further infestations.
