Any member of the order Homoptera’s group of sap-sucking, soft-bodied insects known as an aphid (family Aphididae), also known as a plant louse, greenfly, or ant cow, is roughly the size of a pinhead.
The majority of aphid species have two tubelike extensions on the abdomen called cornicles. Aphids are potentially dangerous plant pests that can restrict plant growth, induce plant galls, spread viral infections, and deform leaves, buds, and flowers.
Let’s get to know about this bug and ways to prevent them from causing any harm to your garden.
Aphids: Physical description
Aphids are tiny, soft-bodied, pear-shaped insects that range in size from 1/16 to 1/8 inches (2-4 mm). They come in a variety of colours, including green, black, red, yellow, brown, and grey.
- Aphids that have reached adulthood may have wings or not.
- Aphids with wings are a tad darker in colour but otherwise identical.
- Nymphal aphids (immature aphids) resemble adults but are smaller.
Aphids can be recognised most easily by looking for two tailpipes (cornicles) at the end of the abdomen. There are cornicles on all aphids, but some have smaller, less noticeable ones.
As they develop, aphids lose their exoskeletons (skins). These skins with a white cast can be observed on plants or embedded in aphid honeydew discharges.
Aphids: Life cycle
Some species’ life cycles entail an alternation between two species of host plants, such as between an annual crop and a woody plant. While some species specialise in feeding on a single plant type, others are generalists that colonise a wide range of plant families. Aphididae, a family that includes all known species of aphid, numbers over 5,000. About 400 of them are found on food and fibre crops, and many of them are major pests of forestry and agriculture as well as a disturbance to gardeners. In a mutualistic connection, so-called dairying ants care for aphids for their honeydew while also shielding them from harm.
- Aphids have an intricate life cycle. Through parthenogenesis, wingless females, often known as stem mothers, breed all summer long.
- Unlike the majority of other insects, these stem mothers generate living offspring (viviparity) as compared to eggs.
- The plant carrying the stem mother and her progeny eventually becomes congested.
- After that, some of the offspring mature into adults with two sets of reasonably large membranous wings.
- They fly to new plants as adults with wings. Male and female production occurs in the late summer.
- The female produces eggs after mating that last winter. Continuous generations can occur in warm climates if an overwintering egg phase is not required.
- Wax gland secretion causes many aphids to have a white woolly ball-like structure.
- Natural enemies, including ladybird beetles, aphid lions, and lacewings, are effective at controlling aphids. However, insecticidal soaps, horticultural oils, and other conventional insecticides help manage them when they are in economically or physically destructive numbers.
Aphids: Distribution
Aphids are found all across the world, but they are most prevalent in temperate regions. Aphid species diversity is significantly lower in the tropics than in temperate zones, in contrast to many other taxa. They may travel long distances, mostly via passive wind dissemination. Winged aphids can also soar during the daytime to altitudes of up to 600 m, where powerful winds carry them. The human transportation of infected plant materials has also contributed to
Aphids: Types
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Apple aphid
The head and legs of the apple aphid (Aphis pomi) are dark. On the apple tree, which is its lone host, it overwinters as a black egg. It produces honeydew, which helps a sooty mould develop.
Rose aphid
The rose aphid (Macrosiphum rosae) is a large, green insect with pink patterns and black appendages. It frequently occurs on its sole host, the cultivated rose.
Cabbage aphid
Small and grey-green with a powdery, waxy covering, the cabbage aphid (Brevicoryne brassicae) is an aphid infestation. On the underside of the leaves of radishes, cabbage, cauliflower, and Brussels sprouts, it grows in groups. In northern locations, it overwinters as black eggs, whereas in southern regions, it has no sexual stage.
Cooley spruce gall adelgid
On the tops of spruce twigs, Adelges cooley produces cone-shaped galls that are about 7 cm (3 inches) long. Adults move to Douglas fir trees to lay their eggs in the middle of summer when the galls open. However, either Douglas fir or spruce may go through the life cycle.
Corn root aphid
Anuraphis maidi radicis, a dangerous pest that depends on cornfield ants, infests the roots of maise plants. The ants keep aphid eggs in their nests over the winter, and in the spring, they transport the newly developed aphids to weed roots, occasionally moving them to maize roots. Corn’s growth is slowed down by the aphid, which also makes plants yellow and wilt. Other grasses are also infected by corn root aphids.
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Rosy apple aphid
Fruit is deformed by the rosy apple aphid (Dysaphis plantaginea), which results in “aphis apples.” Due to its feeding activities, the leaves around it curl, offering some protection from chemical mists. When the aphid returns to the apple tree to lay eggs in the fall, it uses plantain plants as an alternate host. It also harms mountain ash, pears, and hawthorn.
Potato aphid
On rose plants, the potato aphid (Macrosiphum euphorbiae) lays its black eggs, which hatch into pink and green young that consume the leaves and buds of the rose plant. They go to potatoes, the summer host, in the early spring. Every two or three weeks, one generation takes place. It is the disease vector for the tomato and potato mosaic viruses, which damage blooms and vines.
Melon/cotton aphid
The cotton or melon aphid (Aphis gossypii) ranges in colour from green to black. While there is an egg stage in chilly regions, live young are produced all year round in warm climates. Melon, cotton, and cucumber are just a few of the numerous potential hosts.
Greenbug
One of the most destructive pests to wheat, oats and other minor grains is the greenbug (Toxoptera graminum). On the plant, it shows up as yellow patches and has the potential to destroy a whole field. Adults are light green with a dark green stripe running down the back. There are roughly 20 generations every year, and each female gives birth to between 50 and 60 young.
Woolly apple aphid
Apple trees may get damaged or die from the woolly apple aphid (Eriosoma lanigerum), which dwells on the roots. The young aphids are surrounded by white cottony masses.
See Also: Nightshade: Facts about poisonous plants of the nightshade family
Aphids: Damage caused by aphids
Aphid feeding
Aphids consume plant sap using their thin, needle-like mouthparts. They congregate in areas where they can find fresh succulent growth to feed on, such as the underside of tender leaves, unopened flower buds, and growing stems, twigs, bark, and roots.
There are frequently no outward signs of aphid feeding. Extreme aphid feeding symptoms include:
- Curled and twisted leaves.
- Withering foliage.
- Dead or stunned shoots.
- Poorly growing plant.
Honeydew
Aphids inject saliva into the plant they are feeding on to aid in the sap’s digestion. They produce honeydew, a sticky, glossy waste product, after feeding.
- Insects that feed on honeydew, such as ants and yellowjackets (particularly in the late summer and fall), are drawn to the sugar-rich material.
- It can create a sticky mess on the bark, leaves, and things beneath the plant, such as car windshields and patio furniture.
In general, honeydew is harmless, although it can cause leaves to clump together and can promote the development of sooty mould.
- On trees with aphids, sooty mould, a fungus that thrives on honeydew, is frequently observed.
- The fungus can result in black, fuzzy splotches on leaves and branches, but it is not damaging to the tree.
Aphids and plant viruses
The cucumber mosaic virus is one of many plant viruses that aphids can transport. Numerous crops, such as squash, cucumber, pumpkin, etc., as well as annuals and perennials like impatiens, gladiolus, petunia, phlox, and rudbeckia, are susceptible to infection by this virus.
- Viruses can make leaves yellow, curl, or mottle.
- Stunted plant growth is possible.
- Fruit can occasionally be deformed.
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Aphids: How to protect plants from aphids?
- Natural enemies: In gardens, aphids are frequently controlled by a variety of natural predators, such as lady beetles, lacewings, syrphid fly larvae, and parasitic wasps. Since aphids have a high rate of multiplication, it will probably take a while for the predator insects to catch up and lower aphid populations. By avoiding pesticide applications or using low-risk alternatives, you can protect natural enemies. Plant flowering plants that bloom at various periods during the growing season encourage natural enemies.
- Early detection: The key to controlling aphid infestations is early discovery. Since the flight of avian invaders cannot be foreseen, weekly inspections of the plants will help to establish whether management measures are necessary. Check for colonies or clusters of tiny aphids on the undersides of the new leaves and in the bud area. These colonies show that the aphids are established on the plants and that their numbers will soon start to rise quickly. On small plants, it is possible to manually crush or prune away small numbers of individual colonies when they are discovered. In some circumstances, this might offer sufficient control.
- Remove weeds: To lessen aphid attack possibilities, eliminate weeds from your garden. Mustard and sow thistle are two weeds that can host a lot of aphids.
- Use high-pressure water spray: A high-pressure water spray from a garden hose will physically knock aphids off of plants. Additionally, this will aid in clearing away any honeydew or sooty mould that could be present. Since aphids are weak insects, even a heavy downpour can drive them away. In seasons with little rain, you might see a greater number of aphids.
- Use summer oil: On some types of trees and ornamental plantings, summer oils can be used to control aphids. They destroy the insects by smothering them or rupturing their membranes. Check the package for warnings about using oils on delicate plants; some plants’ foliage can become damaged by oils. The possibility of leaf burn can be increased by weather conditions, particularly high temperatures. Spraying dormant oils during the growing season is not advised. Since there is no lasting effect, further applications can be required.
- Use fatty acid salts: aphids respond well to insecticidal soaps or fatty acid salts. They appear to function similarly to summer oils in rupturing insect cell membranes. They need to come into direct contact with the insects and leave no aftereffects.
- Use nervous system insecticides: Many shade trees and ornamental plants are labelled for use with nervous system pesticides, including malathion, Dursban (chlorpyrifos), and Orthene (Acephate) for the control of aphids. Coverage is crucial, much like with oils and soaps, and a second application can be required. Make sure the plant or crop you are treating is listed on the label of the medication.
Now you just have to keep the above information in mind and enjoy gardening.
FAQs
How long can aphids live without plants?
The aphids can only survive for a short time without their living host plants, and they cannot generate a continuous egg stage indoors. After plants are removed, one week should be enough time for all aphids to die away.
What kind of plant do aphids detest?
Aphids can be repelled by planting garlic, chives, leeks, catnip, fennel, dill, and cilantro. Numerous unpleasant pests have been observed to flee when exposed to marigolds. For these garden additions, find appropriate companion plants and put them strategically.