Aphids
Aphid Facts
Aphid Common Names: Blackfly, Greenfly, Plant Lice
Scientific Names: Aphididae/Aphis Fabae/Macrosiphum Rosae
Aphids feed on the sap of most plants; their stems, buds and leaves.
They can be seen generally from April to October or all year round indoors.
Symptoms include:
- Poor or distorted growth
- Drooping leaves
- The presence of Aphids by sight
- Sticky honeydew and sooty moulds.
- Curling leaves.
Ants will be attracted to their sticky honeydew secretions left by Aphids, they will eat the Aphids. Other insects will also help naturally remove Aphids, such as ladybirds and beetles.
Aphid eggs are either oval or chisel-shaped. The eggs are attached by threads or supports. Recently-laid Aphid eggs have a light yellow-greenish colouration, with the shade becoming darker as the eggs mature. Certain Aphid species cover their eggs with wax to make them distasteful to predators.
Aphids can be deterred by pungent smelling plants like onions, garlic, sage, nasturtium, lavender and fennel.
Non-Chemical Treatment of Aphids may include:
- Encouraging Aphid predators like ladybirds, wasps, beetles and Lacewings.
- You can use your fingers to squash and remove Aphids and their eggs.
- Spray soapy water on the entire plant. This will suffocate the Aphids on contact.
You will need to treat infested plants daily due to the vigorous rate that Aphids reproduce.
Some Aphids can transmit plant viruses. This is a particular problem on soft fruits, such as strawberry and raspberry, and some vegetables such as tomatoes and plants of the cucumber/marrow family, as well as on some ornamental plants, such as dahlias, lilies, pelargoniums, tulips and sweet peas. Virus-affected plants should be destroyed to prevent the disease being spread to other plants.
About Aphids
Aphid Lifecycle
A generation of Aphids survives the winter as eggs, which allows them to withstand extreme environmental conditions of temperature and moisture. In spring the eggs on the plant (primary host) hatch, leading to the first generation of Aphids. All the aphids born from the winter eggs are females. Several more generations of female Aphids are born during the spring and summer. A female can live for 25 days, during which time she can produce up to 80 new Aphids.
Spring and summer reproduction occurs asexually – without males. In these cases, the resulting Aphids are basically clones of the mother. In addition, the young are born live rather than as eggs. When the autumn approaches, there is a generation that grow into both male and female individuals. Females fertilized by the males lay winter eggs on the plant where they are, closing the cycle.
Aphids can be winged or wingless. Usually, the first generation to emerge from the winter egg are wingless. However, after several generations there can be a lack of space on the host plant. This triggers the birth of a generation of winged aphids, which can migrate to other hosts.
Aphids come in many colours, shapes and sizes, often with particular host plants. Greenfly and blackfly are the most familiar Aphids but there are also yellow, red, orange and brown types. Whilst most Aphids are found in the garden, some end up our homes and target our house plants. Without the natural predators such as birds and ladybirds, they breed rapidly. They can quickly build up into large infestations if not dealt with promptly.
Aphids are tiny, soft-bodied, sap-sucking insects belonging to the superfamily Aphidoidea.
Ranging from 1/16 to 1/4 inch long, Aphids have waxy, pear-shaped bodies that vary widely in colour, depending on the species (to date, about 5,000 species have been discovered).
Green Aphids (greenflies) are often the most damaging because they blend in so well with leaves and stems that they tend to go unnoticed until their numbers grow out of control. Also common are yellow, grey, red, brown, and black Aphids, and the rather wild-haired, fluffy white woolly Aphids that resemble mealybugs.
All Aphids are characterized by a stylus (a kind of syringe needle) that is used to pierce and suck the sap from the plant. Also, they have a couple of tubes in the back called cornicles or siphunculi through which the animals excrete a kind of honeydew called cornicle wax. For nutrition, Aphids usually feed on the plant’s phloem sap, which is rich in sugars, minerals and other elements. The phloem is responsible for distributing this kind of sap throughout the plant. For water, Aphids draw fluid from xylem, where raw sap runs directly from the roots. This allows them to stay hydrated during hot or dry periods.
