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Where do aphids come from? What do aphids look like and how do I recognize an infestation? You can find out everything about the different aphid species in our profile.
One usually speaks of "the aphid", although we know about 3000 species, of which 850 species occur in Central Europe alone. Not only do they differ in coloration, they also prefer different host plants. Therefore, pretty much any plant can be attacked by aphids. Everything you need to know about the most well-known plant pests can be found here.
Aphid profile
Aphids belong to the group of plant lice (Sternorrhyncha) along with leaf fleas (Psylloidea), scale insects (Coccoidea) and whiteflies (Aleyrodoidea), better known as whiteflies.
The small insects only grow a few millimetres large and vary in color depending on the species. Aphids are usually green, black or reddish in color. The lice are mostly wingless, but winged individuals also occur for dispersal purposes.
Aphids (Aphidoidea) feed exclusively on plant sap and cannot infest animals or humans. To get at the plant sap, the aphids have a proboscis. Most of the plant-sucking lice are so-called phloem suckers. The phloem is a vascular tissue in plants in which the particularly sugary sap is transported. Because the aphids also need other nutrients such as protein, they have to absorb a lot of the plant sap, as there is hardly any protein in it. Most of the sugar is therefore excreted again as honeydew. In addition to ants and mushrooms, beekeepers also enjoy honeydew - this is how the well-known forest honey is produced.
In addition to the food intake, the way of life of the aphids is also very interesting. Many aphid species switch between a winter and summer host. The winter host often only serves as protection for the next generation of aphids. Usually only the eggs surviveaphids the winter. However, if the temperatures remain mild during the cold season, adult aphids can also survive. After such a mild winter, veritable aphid infestations can occur on beans, peas and other herbaceous plants in early spring. In the spring, the aphids start looking for their summer host. Many aphid species still have wings at this time so that they can cover greater distances.
Once a host has been found, the way of life often changes as well. There is an alternation of generations and wingless females are formed that are capable of virgin birth. This type of reproduction allows for very rapid multiplication. This is usually also the time when aphids become a problem for the hobby gardener. Due to the large number of offspring, the aphids can severely weaken and damage plants. If the food source is exhausted, winged females are formed again, which infest plants again. In the fall, females lay fertilized eggs that survive the winter and hatch into a new generation of aphids the following spring.
Tip: Whether plants suffer badly from aphids or not also depends on the fertilization. High-nitrogen, mineral fertilization is more likely to result in vulnerable plants with soft tissues that make it easy for aphids. The organic and potassium-heavy fertilization, for example with one of our Plantura organic fertilizers, ensures balanced growth with strong cell walls, which offers more resistance to the bristles of plant lice.
Where do aphids come from?
Aphids are not only annoying pests, but are also often worn unknowingly as amber pendants. The animals trapped in the amber show that the pests have been around for over 200 million years. Aphids are distributed worldwide and have adapted to a wide variety of conditions. In the Middle Ages it was believed that an aphid infestation was caused by a special rain, the "nephew's rain". Today we know that there are winged individuals that can fly quickly from plant to plant. But where do the aphids come from in our garden? Since aphids lay their eggs on very specific winter hosts in autumn, depending on the species, the animals that hatch from them start their search for a summer host in spring. The black bean aphid (Aphis fabae), for example, likes to overwinter on euonymus (Euonymus europaeus) or snowball (Viburnum opulus). ), whereas the green onePeach aphid (Mycus persicae) overwinters on sloe (Prunus spinosa) or peach trees (Prunus persica). For this reason, it can help not to plant such winter hosts in your own garden.
Aphid species
Among the hundreds of different aphid species, there are a few that are particularly common in our home gardens.
Pea Aphid (Acyrthosiphon pisum)
The pea aphid is a fairly large species of aphid, two to four millimeters long, which, as the name suggests, particularly likes to attack legumes such as peas. It usually only forms small colonies and prefers to attack young shoot tips and flowers as well as the pods of peas and other legumes (Fabaceae). The affected shoots and legumes often wither, contain fewer seeds and the yield can drop significantly. This species does not change hosts and lays its eggs in autumn on hardy legumes for overwintering.
By the way, researchers are very interested in this pest. The lice appear in different colors, such as yellow, green and red, but have the same genetic makeup. How these different colors come about is a current scientific issue.
Green peach aphid (Myzus persicae)
This is a smaller representative of the aphids with a maximum size of two millimeters. The flightless lice are colored green, while the flying generation is black-brown to black. As the name suggests, it hibernates on a peach tree or on sloes. The summer hosts also include the potato and other herbaceous plants. The infestation by the green peach aphid is mainly visible through curled and yellowed leaves. When sucking on different plants, the aphids transmit viruses that can damage your plants, even after the aphids have disappeared.
Black bean aphid (Aphis fabae)
This aphid species is a matt black, sometimes dark green aphid about two millimeters in size. They winter exclusively on the euonymus (Euonymus europaeus) or snowball (Viburnum opulus). From there they attack herbaceous plants such as field beans, potatoes and also beets from spring. AlsoHere the leaves often curl up and viruses are transmitted. The colonies can become very large and therefore severely damage infested plants.
Detecting aphids
Most people don't even notice an infestation of a few aphids, as they hide quite well under the leaves. Only when it comes to mass propagation, countless of the little pests can be seen. They are then partly on the leaves and especially on the freshly formed flower buds and shoot tips. The plant suckers, which are usually two to three millimeters in size, can lead to deformed and curled leaves in the event of a severe infestation. Through their sucking activity, they withdraw a lot of water locally from the plant and the tips of the shoots hang down. When aphids suck up the sugary plant sap, they always excrete a large part of the sugar in the form of honeydew. This attracts more ants, which can be an indication of an aphid infestation. If the honeydew falls on the lower leaves, a sticky layer forms there, which is also typical for aphids.
Pests of aphids
Infested plants are weakened and fruits or leaves are deformed due to the sucking activity and thus the withdrawal of sugar, proteins and minerals, as well as the aphid saliva. This can reduce the yield and quality of tomatoes, peppers, lettuce and cucumbers, for example. Plants can also be damaged by infection with viruses transmitted by aphids. If an aphid sucks on a virus-infected plant, the aphid also ingests the virus. If the louse now changes host plants and starts sucking on the new plant, the virus can be transmitted. This can already happen with an infestation by a few animals. Yellow-green, mosaic-like leaf discolouration is a common symptom of plant viruses. But don't worry: Plant viruses are not dangerous for us humans.
Black and sooty mold fungi can form on the leaves on the honeydew that is excreted. As a result, the plant receives less light and is additionally weakened. Crops overgrown with these mushrooms should no longer be eaten.
What does aphid damage look like?
- deformed leaves or fruit
- possible transmission of plant pathogenic virusesand resulting leaf discolouration
- Black mold on honeydew layer on leaves
In the case of these types of damage, we recommend that you take biological measures as soon as possible to combat the aphids. Biological pesticides based on neem oil are a natural and very effective way to get rid of aphids. Our Plantura organic pest-free neem is based on this valuable oil. The herbal remedy ensures that the sucking activity of the lice is quickly stopped and can be used easily both outdoors and in the home. Before use, be sure to read the instructions on the enclosed leaflet.
Aphids are particularly common on roses in early summer. Here they can damage the flower buds so badly that the flowers are in danger. We'll show you how to get rid of aphids on roses naturally.