These are one of the most common garden pests and can be found on all sorts of plants both indoor and out. They live by sucking sap from the plant which can leave them damaged or inedible.
How to identify greenfly?
They are very small, ranging from 1-3mm in length and have 6 legs. Their bodies are a teardrop shape and light green as well as having small transparent wings. They are usually easy to notice as they cluster as groups usually on stalks or undersides of leaves.
Damage they cause?
As greenfly are sap-sucking creatures that cause quite a bit of damage to plants when left to get out of control. This can cause the plants to have stunted growth, cause deformations on leaves, buds or stems and decrease vigour.
They also produce a sticky substance, known as honeydew which they leave on plants and can be a perfect environment for moulds and fungus to grow.
How to treat them?
You can try introducing other insects that will feed off of the aphids, such as ladybirds, lacewing larvae and parasitic wasps.
You can also try removing and squashing them by hand if the infestation is still small but greenflies multiple fast so this is not always effective.
If the plants are strong enough, you can try spraying the plants with water to blast the greenfly off.
Insecticide soaps can be found in some garden stores.
Aphids dislike alliums and catnip so by planting them around the garden you can discourage them.
Ants protect aphids, so if you notice you have ants too, try to get rid of them.
You can buy pesticides or insecticides that can kill off greenfly, but always read the labels.
Bifen XTS Bifenthrin Concentrate
Essential IC3 Insecticide Concentrate
Martins Permethrin 10% Indoor and Outdoor
Greenflies can produce both live young and eggs.
In summer, females called the stem mothers can reproduce without fertilization, which is when they produce living young (all female) rather than eggs. When the plant they host becomes overcrowded or they are in danger from predators the young will develop into winged adults and fly to other plants where they will then lose their wings and start to produce live young again.
In the late summer, they will start to produce both male and female greenflies that will mate. The females then lay eggs that will survive through winter.