Aphids, often called plant lice, are one of the most common pests on houseplants. There are over 5,000 species of these tiny insects, classified into a unique . Despite their small size, aphids have a strong sucking mouthpart. This makes them formidable pests for your indoor plants.
Diversity in Appearance
Aphids exhibit a wide variety of appearances, adapting well to the plants they infest. As a result, they can be almost transparent. They can be whitish, black, lettuce green, dark green, yellow, or pale pink. They can have wings or not. The average body size of an aphid is 1 mm.
Reproductive Capabilities
A unique feature of aphids is their extraordinary fertility and rapid reproduction rate. There are both male and female individuals, but males make up no more than 2% of the total population. If there are too few males or if conditions are bad, females can reproduce alone. An adult aphid can lay up to 100 offspring. They can reproduce in 14 days. This is why aphids can devastate a plant. Each colony has a few winged insects. Their task is to scout and find new habitats for the colony. The wingless individuals are for reproduction. Identifying aphids on houseplants is easy. They gather on young shoots and buds and hide under leaves.
Signs of Aphid Infestation:
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Curled, deformed, yellowed leaves;
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Drying of stem tips;
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Sticking of leaves;
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Massive bud drop;
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A shiny, sticky liquid on stems and leaves.
Aphids excrete sticky residue called honeydew. It attracts sooty mold and grey mold. The presence of these pests always leads to fungal and viral infections in plants.
Species Diversity
Much of the is in Eurasia. Canada alone has 1,500 identified species. Which species infest indoor plants?
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The cotton aphid devastates melon crops. But, it can easily adapt to indoor conditions. It targets decorative citrus plants and hibiscus. You can recognize this species by its bright yellow or green body.
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Rose aphids affect all types of roses, including mini indoor varieties. They can move to other flowering plants in homes or greenhouses.
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The oleander aphid is large, with a body length of 2.5 mm. It is from the Mediterranean. Introduced imported fruits and spreads in orchards and indoors.
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The green peach aphid is often found on citrus plants. It is also known for spreading the deadly tristeza virus. The virus kills the plant. This aphid can also live on flowering shrubs.
Plants at Risk of Aphid Infestation
Aphids, being phytophagous, have a sucking mouthpart. They pick plants with succulent leaves. They are easier to pierce with their proboscis. Large, fleshy leaves have lots of juice reserves. These pests target indoor citrus. They also target anthurium, African violet, begonia, geranium, jade, and kalanchoe. They affect all orchids, petunia, and fuchsia.
Specific Plant Vulnerabilities
Indoor mini roses often have rose aphids. Plumeria, dipladenia, and blooming Asteraceae may suffer from oleander aphids. The green (citrus) aphid targets bellflower and indoor periwinkle.
Experienced gardeners have observed that aphids never infest palm trees. They also avoid plants that exude toxic milky sap, such as spurge and various types of ficus.
Prevention of Aphid Infestations on Houseplants
To protect indoor plants from aphids, you must understand how these tiny pests get into homes. Despite their tiny size, aphids can hitchhike into homes. They may even come with groceries.
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Pets and family members may carry aphids on their clothing or in their hair. This happens after time outdoors, especially in warmer months.
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Bouquets contain gardens and wildflowers. They can give aphids to houseplants.
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Aphid larvae can find their way into pots through contaminated outdoor soil.
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Winged aphids can enter homes through open windows.
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Plants placed outdoors in gardens or on balconies can become infected.
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People know that ants spread aphid larvae.
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Farmers do not treat leafy greens and cruciferous vegetables with insecticides. This lets aphids move from these products to indoor plants.
Failure to adhere to quarantine guidelines for new houseplants poses a risk. Whether you receive a potted plant as a gift or buy one from a store, you should isolate it for 7-14 days. Inspect all above-ground parts of the plant during this period. After this quarantine, only place the new plant near other indoor plants.
Methods to Control Aphids on Houseplants
Aphid populations can multiply fast. So, it’s vital to tackle them at the first signs of infestation. If aphids have introduced harmful fungi and viruses, comprehensive measures become necessary. To fight the infestation, you may also need to use fungicides. You’ll use them along with insecticides.
Mechanical Methods
These involve manual pest removal techniques. They work only when pests are still few. Here’s what you can do:
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Crush all visible individuals with your fingers.
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Cover the pot’s soil with plastic and give the plant a warm shower to wash off the insects with a water stream.
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Cut off all infected plant parts along with the pests.
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Wipe the foliage with medical alcohol.
Biological Methods
The first approach is to treat infected plants with non-toxic bio-pesticides. Examples include “Sevin (Carbaryl),” “Captain Jack’s Dead Bug Brew,” and “Fitoverm.” These contain by-products of soil bacteria or their live strains. These do not harm the plant or home occupants but suppress aphid reproduction.
Another biological method is the use of special oil emulsions. When sprayed, they create a fatty film on leaves and stems. This film does not affect photosynthesis or transpiration. But, it prevents pests from piercing the plant.
Introducing natural predators is also a biological control strategy. Many gardeners add ladybugs to their gardens. Ladybugs eat many types of aphids and stop them from spreading on plants. Many think ants can drop aphids. But, in fact, ants eat the honeydew aphids produce and protect them from predators. Thus, using ants to control aphids is ineffective.
Chemical Methods
In cases of severe infestation, the use of toxic substances might be the only solution. Insecticide treatments can be contact-based or systemic. Spray contact insecticides onto the plant to kill adult insects and larvae. Farmers apply systemic insecticides to the soil. The plants’ roots absorb them. They contaminate the cell sap that aphids eat.
Effective chemical aphid treatments include:
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Malathion is a popular insecticide. It has a broad action and is good for fighting aphids and mites.
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Vertimec is another insecticide that kills adults. They die off 2-3 hours after treatment.
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Bonide Insecticidal Soap is insecticidal. It is safe for humans. It is ideal for treating indoor plants.
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Neonicotinoids – a systemic product that eradicates all types of aphids.
Traditional Methods for Combating Aphids on Houseplants
These are inexpensive remedies that are usually available. They are suitable for use as preventative measures or as emergency treatment options. But, traditional methods are often less effective.
Mustard Powder Solution
Dissolve 2 tablespoons of white mustard powder in 1 liter of boiling water. Let it steep for 12-16 hours, then strain and treat all above-ground parts of the plant. You can perform this procedure every other day for two weeks. Ensure that the potent solution does not harm the plant.
Celandine Infusion
Aphids avoid plants that emit toxic milky sap. Take 200 grams of fresh celandine and pour 1 liter of hot water (not boiling) over it. Let it sit overnight, then strain and treat the affected plant. Perform this procedure twice a week. If wild celandine is not available, use houseplants that aphids avoid. For example, use the toxic spurge.
Tar Soap Solution
Dissolve 30 grams of tar soap in 1 liter of warm water. Use the solution to spray all the plant’s above-ground parts. Make sure to protect the soil from the solution. If tar soap is not available, you can use household soap instead. But, the dosage will differ: 50 grams of soap per 1 liter of water.
You can protect your indoor plants from aphids. Do this by understanding the habits and weaknesses of aphids on houseplants. Use a mix of preventive and active measures. Also, stay vigilant for signs of infestation.
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