• Identification tips for spotting aphids in greenhouse plants
• Control methods using natural predators and cultural practices
• Prevention strategies to keep infestations under control
• Protect harvests by tackling aphids early
• Support beneficial insects with attractants
How to Identify Aphids in the Greenhouse
Aphids are small, soft-bodied insects often green, black, white, yellow or pink depending on the species. They usually cluster on young leaves, new shoots and the undersides of foliage.
Common signs include sticky honeydew, curled or yellowing leaves, distorted growth, and the presence of ants. Ants farm aphids for honeydew, making infestations worse, so both pests need controlling. Treat the ants before you treat the aphids.
Why Aphids Thrive in Greenhouses
Greenhouses provide warmth and humidity, conditions that encourage rapid breeding. Populations can increase in just days, quickly spreading between plants. Enclosed spaces also mean fewer natural predators, allowing colonies to multiply unchecked. This makes regular inspection essential to prevent outbreaks before they take hold.
The Damage Aphids Cause to Greenhouse Plants
• Weaken plants by draining sap and vital nutrients
• Spread viruses that stunt and deform plant growth
• Cause sticky honeydew deposits that attract sooty mould
• Lead to curled, yellowed or stunted leaves
• Reduce harvests from fruiting plants such as tomato, pepper and cucumber
Controlling Aphids in the Greenhouse
Regular monitoring helps catch aphid populations early. Manual removal works for small colonies, while stronger outbreaks benefit from biological control using ladybirds, lacewings or parasitic wasps like Aphidius colemani.
Sticky traps can monitor flying pests. Gardening Naturally offers Aphid Predator Attractant Beneficial Insect Attractant, which helps support these beneficial insects for longer-term control.
Using predator bait for natural aphid control in greenhouses
One of the most effective natural methods to reduce aphids in a greenhouse is to encourage the insects that feed on them. Predator bait sachets are designed to do exactly this.
They release a carefully balanced mix of plant-based scents, the same chemical signals plants naturally produce when under attack. These scents act like a beacon, drawing in insects that prey on aphids and other soft-bodied pests.
By hanging a sachet above fruit trees, vegetable crops, flowers, or greenhouse plants, you can attract lacewings, hoverflies, minute pirate bugs, and parasitic wasps. Each of these predators targets aphids during different stages of their life cycle.
Lacewing larvae, for example, are known as “aphid lions” for their ability to consume large numbers quickly. Hoverfly larvae are equally efficient, while tiny wasps lay their eggs inside aphids, stopping infestations from spreading further.
A single sachet will continue releasing attractant for up to six weeks, depending on the weather, and can be placed wherever aphids are most likely to appear. Unlike chemical sprays, predator bait is safe for pollinators, children, and pets, while supporting a balanced garden ecosystem.
For the best results, start using them early in the season around March or April, and continue throughout the growing period to keep populations under control.
Preventing Aphid Infestations in the Greenhouse
• Cover vents and windows with Veggiemesh insect netting to block entry
• Clean doors, vents and frames to reduce access points
• Avoid excessive nitrogen fertiliser that produces soft growth
• Remove weeds and plant debris that harbour pests
• Ventilate to lower humidity and slow aphid reproduction
• Rotate crops to prevent repeat infestations
Benefits of Tackling Aphids Early
• Protects greenhouse plants from prolonged damage
• Lowers risk of virus transmission between plants
• Supports stronger growth and healthier harvests
• Reduces reliance on chemical sprays later in the season
• Encourages a balanced greenhouse ecosystem