• Organism

Green Peach Aphid

These small sap-sucking insects are prolific pests, due to their pesticide-resistant genes.


Scientific name: Myzus persicae

Length: 1.7-2 mm

Habitat:  In temperate or tropical climates, on or near the plants which they eat

Diet: Sap

Aphids are small insects, more commonly known as greenflies or blackflies, that live on the undersides of leaves. Green peach aphids are yellow-green in colour and have red eyes. They are the most common aphid in the US and are found all over the world in temperate and tropical climates. 

In warmer months, green peach aphids reproduce asexually, laying nymphs on a range of plants including vegetables like cabbage, potatoes and peppers, as well as flowers such as sunflowers. In the warmest regions, up to 20 generations can be born in a single year. As the weather cools,  they lay eggs on trees of the genus Prunus - which includes peach, nectarine, cherry and almond trees - that hatch in the following spring. Aphids suck the sap of the plants that they live on as their food source. 

Aphids have a curious symbiotic relationship with ants. Ants will ‘milk’ aphids to get honeydew, a sugary waste product that aphids produce as a result of sap-sucking. In return for this food source, ants protect aphids, sheltering them from rain, helping them to move from one plant to the next and sometimes even destroying the eggs of predators such as ladybirds.

Scientific significance.

The green peach aphid’s success in being able to colonise around 400 different plant species is a headache to the agricultural industry, as their sap-sucking can devastate crops, especially as they can act as vectors for over 100 different plant viruses. 

Attempts to prevent crop losses due to aphid colonisation have so far been unsuccessful: incredibly, they have developed resistance to around 71 different pesticides in just 50 years. This has made the green peach aphid an ideal model in which to study mechanisms of pesticide resistance. 

What Earlham Institute is doing.

We are exploring the evolution of pesticide resistance in aphids with the aim of reducing crop loss and increasing food security.

To find new ways to control the green peach aphid, a greater understanding of how this insect adapts to pesticides is needed - and this is what our research focuses on. So far, few investigations have focused on the early steps of genetic agrochemical resistance regulation. This study will identify genes and genetic variants that enable the green peach aphid to rapidly evolve resistance to pesticides and adapt to new plants.

Our research will help the agricultural industry to identify new potential targets for pesticide development. In turn, this will have an impact on agriculture and help improve food security.