Aphids are destructive pests that manage to sneak their way into many gardens. These tiny, slow-moving creatures can significantly weaken indoor plants and fruits. It is relatively easy to identify and get rid of the situation. A lot of people keep indoor plants, and they need protection from aphids. Nobody likes an infestation.
What are Aphids?
Aphids are small sap-sucking insects and among the most destructive insect pests on cultivated houseplants. They are members of the superfamily Aphidoidea. Common house names include blackfly and greenfly. Individual Aphids within a particular species can vary widely in color.
They act as vectors for plant viruses and disfigure plants by laying down honeydew and the subsequent growth of sooty molds in addition to weakening the plant by sucking sap. Aphids possess the ability to rapidly increase in numbers by means of asexual reproduction and telescopic development, which makes them a highly successful group of organisms purely from an ecological standpoint. This makes them beneficial insects.
Aphids seem to crawl their way into every garden and house plant. Aphids are tiny and soft-bodied insects. Large numbers of aphids can weaken plans significantly as they feed by sucking the nutrient-rich liquids out of plants. Many generations of aphids can occur in one season, so it’s important to get them under control and as aphid infestation is quick.
1. How to identify an aphid
Adult aphids are under ¼ inch, and you might overlook them. Aphid control is easy as they tend to move quite slowly. Aphids can be black, white, gray, brown, light green, yellow, or even pink. These plant pests could also have a waxy or woolly coating. Tiny aphids have pear-shaped bodies with long antennae, and the nymphs look similar to the adult aphid. An aphid will have two cornicles (short tubes) jutting out from its backside.
An aphid is usually wingless, but when populations become crowded, most species can develop a winged form. So when food quality suffers, an aphid can reproduce, travel to other plants, and start a new aphid population. They usually feed in big groups, but you might occasionally view a single aphid or in small numbers on an infested plant.
Different species of aphids can be specific to certain plants, although, in general, they feed on a wide variety of plants. For example, some species include cabbage aphids, melon aphids, woolly apple aphids, bran aphids, potato aphids, and even green peach aphids.
Unlike plant bugs, leafhoppers, and other insects that are confused with them, most aphids are slow-moving even when disturbed.
2. How Aphids Damage Plants
Aphids remove plant sap from phloem sieve elements that significantly weaken the leaves of the plant and result in lower quality fruit. Heavy aphid infestations can also result in houseplant death. The phloem is an amino acid poor substrate, so aphids must process a large quantity to gain products necessary for protein synthesis.
Their gut is modified into a filter chamber so aphids can shunt larger quantities of phloem, which is excreted in a carbohydrate-rich exudate termed as ‘honeydew.’ These pear-shaped pests produce large quantities of honeydew which can cover the fruit and leaves. There is a growth of black sooty mold due to the sugary substrate.
On the surface of leaves, this sooty mold can become so thick that it reduces photosynthesis on the foliage resulting in poor quantity and quality of fruit. Aphids are also effective vectors of a number of plant viruses.
Adults and nymphs feed on plant juices, attacking stems, leaves, flowers, buds, fruits, and possibly roots. They especially like succulent new growth, so it is vital to control aphids. Varieties such as the green peach aphid feed on a variety of plants, while others, such as the rosy apple aphid, focus on a single or just a few plant hosts.
3. How to identify damaged plants
Identify the damage in plants by looking for curling, stunted, misshapen, or yellowing leaves. It is vital to check the undersides of the leaves of your plants because aphids love to hide there. Check the leaves of the plants, especially the undersides of the leaves, for damage. Fruits and flowers can become deformed or distorted due to these fungus gnats. Some varieties also cause galls to form on leaves or roots.
Look for the tell-tale sign that aphids have been sipping sap from plants. The stems or leaves will be covered with a sticky substance called honeydew. This sugary liquid or sticky substance produced as waste can attract other insects like ants which gather the substance for food. When aphids feed on trees, their honeydew can also fall on cars, driveways, outdoor furniture, and so on.
This honeydew also encourages a fungal growth called sooty mold, causing leaves and branches to appear black. They can also transmit viruses between plants plus attract other insects such as ladybugs to prey on them. Generally, low to moderate numbers of leaf-feeding aphids aren’t damaging on trees or in gardens. However, large populations can stunt shoots and turn leaves yellow. In some cases, you might have to dispose of the entire plant. However, aphid damage is reversible.
4. How different vegetables are infested
Some species can also inject a toxin into plant leaves which distorts growth. Viruses are often transmitted from plant to plant. Vegetables such as cucumber, pumpkin, squash, bean, melon, lettuce, potato, chard, and beets have aphid transmitted viruses associated with them.
Infection of aphids on houseplants can occur even when their numbers are low. It takes only a few minutes for the virus to be transmitted, while insecticides take much longer to kill them. Heavy infestations of root and crown aphids on carrots may weaken tops, causing them to tear off when carrots are harvested.
Different species damage parts of plants other than shoots and leaves. The lettuce root aphid is a soil dweller that attacks roots in summer and spring, causing lettuce to wilt and occasionally die. In fall, these tiny aphids may move to poplar trees. The woolly apple aphid damage woody parts of apple limbs and roots, often near pruning wounds, and can cause overall tree ill-health if roots are infested for several years.
The Aphid Life Cycle
All living things have life cycles, and often these life cycles are beautifully strange and unexpected. A species’ life cycle is the series of predictable major events from its first moment until death. When considering this tiny insect’s life cycle, you can’t avoid focusing on its curious and different reproduction strategies. Also, the kinds of host plants it lives on at different stages of its life make them unique.
1. The Process
The life cycle of this species is complicated. Wingless females, called stem mothers, reproduce by parthenogenesis (without fertilization) throughout the summer. These stem mothers are unique in that they produce viviparity (living young) instead of eggs, an occurrence in most other insects.
Eventually, the plant containing the stem mother and offspring gets overcrowded. Some offspring develop into adults with two pairs of large membranous wings. Now these winged adults fly to new plants. Both males and females are produced in late summer.
After they mate, the female will lay eggs that survive the winter. There is mostly no need for an overwintering egg stage in warm climates, and continuous generations occur. There are some features uniting nearly all the aphids, although each of the many aphid species has its life cycle. One feature uniting them is that they are incredibly prolific. They can produce up to five offspring per day for up to thirty days!
2. Variation with seasons
During spring, the egg hatches, giving birth to a wingless female aphid who soon gives birth to new wingless females. A multitude of wingless female generations survives until hot weather arrives or the plant on which they live dies. Sometimes, some of the females grow wings and fly off.
This new generation of female winged aphid may find a plant host of a completely different species from that on which their spring generations developed. For example, green peach aphids overwinter as eggs on peach and related trees, but they can move to various crops and weeds in spring. Later, they move onto potatoes, only in the fall returning to peach and other trees.
Typically late in the year, when it’s time to move back to the plant species on which the aphid overwinters, some aphids develop into males as well as females. Sexual reproduction then takes place, and the mated females return to the winter plant-host to lay fertilized eggs. Then next spring, the females hatch from the eggs, and therefore, the cycle begins again, with no males in view.
Young aphids are termed nymphs. Nymphs molt by shedding their skin at-least four times before becoming adults without any pupal stage. Some aphid species produce sexual forms that mate and produce eggs in winter or fall, providing a more hardy stage to survive harsh weather and the absence of foliage on deciduous plants. There are cases where aphids lay these eggs on an alternative host, usually a perennial plant, for winter survival.
3. Reproduction of different species
Turnip Aphids live in a part of the country where winters are not so severe, so that an overwintering “egg stage” is not needed. Throughout the year, reproduction is often entirely or nearly entirely parthenogenetic.
The white woolly-ball appearance of many aphid species is the result of a wax-gland secretion. Aphid infestations are often controlled by natural enemies such as aphidlions, ladybug beetles, and lacewings. When economically or aesthetically damaging numbers are present, they can be controlled by various methods like pesticides and oils.
In warm weather, various species of aphids can develop from newborn nymph to reproducing adult in about seven to eight days. Each adult aphid can produce up to 80 offspring in a week, so aphid populations can increase with great speed.
Another amazing feature of most aphid species is that reproduction during at least part of its life cycle can be accomplished without the help of male aphids. Offspring are born from females without the benefit of sexual reproduction. The process is known technically as parthenogenesis. When mothers reproduce in this way, instead of laying eggs, they directly give birth to smaller editions of themselves.
How to treat Aphids
Aphids are natural predators. Aphids may move slowly but can reproduce quickly, which results in heavily infested plants, so aphid control is necessary. After identifying aphids as a reason for the infested plant, it is now time to get rid of common problems. There are many options, most of them non-chemical such as neem oil to kill bugs.
1. Dip in water
A strong stream of water sprayed on your plants is enough to kill or wash the aphids away. They are usually unable to find their way back to the same plant. For light infestations, a cotton swab can be used, or you can brush them away using your fingers to kill aphids.
2. Wash them away
To maintain delicate foliage, first dip the entire plant in water to dislodge aphids on houseplants or use a cotton swab. Turn the houseplant upside down, and using a bucket, dip into clean, room-temperature water.
3. Use a homemade insect spray
A mild solution of water and a few drops of dish soap can be used by wiping or spraying the houseplant with soapy water to get rid of aphids on houseplants. For a homemade recipe of soap, spray mix 1 tsp liquid dish soap, 1 quart of water, and a pinch of cayenne pepper. Use this soap spray undiluted every 2-3 days for 2 weeks.
4. Use Insecticidal Soap
Horticultural oils, insecticidal soap, and neem oil are effective in killing these pests. Be sure you follow the application instructions provided. You can also buy insecticidal soaps on the market like Safer’s Insecticidal Soap. Homemade soaps can be made using dish detergent. Products free of additives and perfumes work well with plants.
First, mix soap with 1 teaspoon per gallon and increase as necessary to create soapy water. Focus on the undersides of leaves while spraying. Avoid spraying on the soil.
5. Apply Rubbing Alcohol
Aphids on your houseplant can be killed easily when coated with a swab dipped in rubbing alcohol. Dilute with water if needed to kill them.
6. Remove damaged plant part
A simple and effective, and natural way is to remove the damaged part of the plant and dispose of aphids on houseplants. This is optimal for a heavy infestation to get rid of aphids.
7. Hang sticky traps
Strips or sheets of sticky paper can be hung around your houseplant to get rid of aphids and will trap any visiting insects. You can buy them online or at garden centers.
8. Use Chemical Spray
It is best to use natural ways, but you face a severe infestation, then treat the plant using a spray containing imidacloprid, pyrethroids, or pyrethrins. Pyrethrin-based sprays are the best as they have low toxicity.
Another non-toxic, organic material that gets rid of aphids is Diatomaceous earth (DE).
How to prevent Aphids
There are various beneficial insects such as lacewings, parasitic wasps, and ladybugs that will feed on aphids. You can order these online to keep populations controlled from the start. Spray dormant horticultural oil to kill overwintering aphid eggs on fruit or shade trees and prevent mold.
Another natural to get rid of aphids is companion planting. For example, aphids are repelled by catnip. They are extremely attracted to nasturtium and mustard. Plant these near valuable plants to trap aphids. Check these plant traps regularly.
Nasturtium will spoil the taste of tree sap and help keep aphids off broccoli. Chives and garlic repel these pests when planted near peas, rose bushes, and lettuce.
Use alcohol to control aphids
Isopropyl alcohol (also known as rubbing alcohol or isopropanol) works well to get rid of aphids. Be sure it doesn’t contain any additives. Ethanol (grain alcohol) is one of the best options.
Alcohol usually comes in 70% strength (or 95% purchased commercially). Mix equal parts 70% alcohol and water to make an insecticidal spray. If you use 95% alcohol, then mix 1 part alcohol to 1 ½ parts of water.
Alcohol can also be added to soapy combinations to increase the effectiveness of a spray bottle. For example, combine 2 cups of alcohol, 1 tablespoon liquid soap, and 5 cups water. Be sure to conduct a test patch and check after intervals how the plant is responding to these treatments.
You can now choose the best to get rid of aphids on houseplants. Get rid of aphids using neem oil and protect your indoor plants. Another great option is horticultural oil. Aphid control and prevention can be easy, natural prevention is better than an infested garden/ plant.
Aphid infestation can make you lose your valuable plants, so get rid of aphids as soon as you spot them. Your indoor plants or garden can stay free of aphids if you follow these simple steps.
James Fields is the founder of Gardener to Farmer. His passion for gardening goes back to his childhood days when he would visit his grandfather during the holidays and help him with the plants in the backyard. This has now translated to creating a dependable resource for gardening.