Houseplants get attacked by many pests. These pests cause extensive damage to a plant’s health and impact its cosmetic value. So, the presence of houseplants pests is harmful to them and a nuisance.
The pest infestation of houseplants includes spider mites, scale insects, fungus gnats, whiteflies, and aphids. That’s why houseplants require protection from insect pests and proper growth conditions to flourish.
Houseplants may get these pest infestations during summer (when outdoor or quarantined) and purchase new plants.
The pest feeding of houseplants interferes with plant growth and causes injuries. Such scale insect damage involves downward curling of houseplant leaves, yellowing, and falling leaves. When scale insects are in high numbers, plants may die due to severe damage.
Note: Another important factor in houseplant insect pest infestation is introducing already infested plants in interior spaces as a new purchase or gift from someone. To avoid such conditions of houseplant health compromise is, follow precautions. For example, isolate the all-new plants for at least three weeks from the existing indoor plants. During this time, carefully inspect them for pest infestations.
What Are the Best Methods for the Control of Houseplant Pests?
A breakdown of best practices for the control of houseplant pests:
Keep Houseplants Healthy to Repel Pests
There are fewer chances that an insect pest infects a healthy plant. Healthy indoor plants have active defenses to ward off insects and injuries, therefore, keep your indoor plants healthy by providing them with proper indoor growth conditions.
Always choose the houseplants that best match the indoor environment and provide good care and attention plants.
What Are the Proper Growing Conditions for Houseplants?
Keep the indoor environment moisture-free and clean. Place the indoor plants in suitable spaces to get more sunlight. Do not overwater the houseplants because high moisture levels in potting soil will attract small insect pests and suck plant sap.
Always understand each houseplant’s water and nutrient requirements and feed them accordingly.
- Water the plants at the base, not on the leaves
- Always ensure the soil is dry between watering
- Choose pots with drainage holes
- Ensure water is draining well, and do not let the entire plant stand in water.
- Do not overwater the plants and always allow water to drain entirely because standing water would cause root rot and encourage the infestation of fungus gnats.
Clean Potting Soil
To avoid infestations of plant pests, permanently sterile the potting soil with 3 percent hydrogen peroxide to kill overwintering eggs and larvae of spider mites and fungus gnats. Always use clean pots or pure them before planting bleach and soap dilutions.
Do not use garden soil for potting plants, or you can use commercially prepared potting soil for healthy indoor plants.
Keep Indoor Plants Clean
Keep potted plants clean and remove dead, fallen leaves from soil surfaces. Damp the leaves with wet cloths to remove dust particles and scale insects secretions (honeydew).
To discourage the neighboring house plant infestations, prune the infected plant parts, leaves, and branches with scissors.
Keep in Mind the Nutritional Requirements of Houseplants
Do not overfeed the plants and always follow the nutrition specified charts for each plant. Actively apply the fertilizers when plants are in the vegetative growth stage or during spring. After that, only fertilize when it is essential or if the plant shows any nutrient deficiency symptoms.
Non-Chemical Control of Houseplant Pests
The non-chemical control methods for common houseplant pests are:
Washing of Tiny Insects to Prevent the Indoor Plant Injuries
Many houseplant pests can be controlled by washing plants periodically with a stream of water. This method is helpful in the removal of more giant and tiny flies. In addition, washing houseplants prevents the damage of aphids and spider mites.
Furthermore, small plants can be washed off in sinks and larger plants in a shower.
Note: If you use cloth wipes for plant foliage rubbing, change clothes in each plant to avoid the spread of insects between hosts.
Handpicking of Houseplant Pests
Plant pests significantly more giant insects can be controlled through handpicking. Handpicking of scale insects and mealybugs (soft-bodied insects) helps in the control of these pests. Regular checking and picking off insects through a handheld vacuum prevents the pest population expansion.
In this way, slugs, snails, mealybugs, fungus gnats, whiteflies, and millipedes can be removed from indoor spaces.
Cultural Control of Plant Pests
Always bring those houseplants compatible with the indoor environment (humidity, air circulation, and temperature).
Once the houseplants are in, provide them with proper and healthy growing conditions because slight changes in the indoor environment attract various pests. For example, excessive nutrient applications and moist soil favor the fungus gnat larvae and adult female gnats for egg-laying.
On the other hand, a scorching and dry environment indoors attracts spider mites and favors their fine webbing process and plant damage.
The good sanitary conditions in interior spaces also discourage common houseplant pests and infestations. Remove and discard plant parts with severe damage and infestations because the injuries on these plant parts can not be recovered and controlled. The reason is it needs lengthy efforts to get rid of insect pests. It is also best to remove and discard the infested plant parts. These may act as a source for the infestation of other plants.
Another best way to get rid of houseplant pests is the practice of periodic “host free” intervals to cause the starvation of insects to die without feeding.
Sticky Traps for the Control of Common Houseplant Pests
Yellow sticky traps can also be used to get rid of houseplant pests. These traps successfully control aphids, whiteflies, fungus gnats, and springtails. However, these sticky traps are not effective for larval or younger stages. Instead, they trap adult pests effectively.
These traps can easily be made by cutting bright color cardboards and covering them with sticky material or can be bought commercially available.
Biological Control of Common Houseplant Pests
Beneficial insects or natural enemies of houseplant pests play a vital role in managing them. These natural predators feed on them and lay eggs on or in their bodies. As a result, they can control the problem of houseplant pests to acceptable levels.
These natural enemies are commercially available and can easily be maintained. However, the spray of chemicals can kill these beneficial insects in indoor plants.
Predatory mites can successfully control spider mites. They vigorously feed on all stages of spider mites and help prevent them in indoor spaces.
Adult lacewings help in the control of whiteflies and aphids. All stages of green lacewings feast on all stages of these tiny flies.
A brown lacewing larva feeds on adult aphids and manages its populations on houseplants. These lacewings are the most effective predator of houseplant pests and control their problems at acceptable levels.
Predatory beetles eat mealybugs and control their numbers at acceptable levels. An adult beetle feasts on adults and eggs and larvae of mealybugs. However, these predatory beetles once required larger populations of mealybugs for their establishment. Once they are established, they continue to feed on mealybug and prevent plants from their potential damage.
Another most effective eater of aphids is aphid predator midge. They feed on aphids and prevent houseplants from the damage of sucking houseplant pests. In addition, the larvae of aphid midge are the killers of aphids and require higher indoor temperatures for their activity.
Chemical Control of Houseplant Pests
If the non-chemical methods are not working to eliminate the problem of indoor pests, then consider using chemical control methods. The chemical control methods for the common houseplant pests involve a spray of insecticides, pesticides, neem oil, insecticidal soap, plant leaf oil extracts, alcohol rubbing, and bacterial strains application.
The Spray of Pyrethrins and Pyrethroid Insecticide
Pyrethrins spray effectively manages fungus gnats and other most common houseplant pests. The pyrethrins spray safe for indoor environments because they are non-toxic to pets beneficial insects and have short persistence. Pyrethrins are natural products that are derived from pyrethrum (daisy).
There are also “synthethic pyrethrins” or pyrethroids commercially available and used to control houseplant bugs. These chemicals are based on the synthetic chemistry of natural pyrethrins resmethrin, permethrin, and sumithrin.
Just like pyrethrins, pyrethroids are fast-acting insecticides with short persistence. As a result, they effectively manage the foliage pests without causing any harm to beneficial insects.
These insecticides are absorbed into the insect body and kill them by interrupting their physiology. The systemic insecticides are available in granules and applied in potting soil to soak plant roots and kill larvae and eggs.
Bacillus thuringiensis var. israelensis
It is a natural soil-occurring bacteria that can control many insects. These bacteria feed on larvae, pupae, adults, and eggs. It falls in microbial insecticides and is commercially available Gnatrol and Knock-Out Gnats.
It controls caterpillars of Lepidoptera in vegetables and fungus gnats larvae in houseplants. The H-14 strain of Bacillus thuringiensis controls houseflies, mosquitoes, and spider mites.
Precautions for the Use of Pesticides
Always keep in mind the following instructions while spraying chemicals in an indoor environment:
- Do not spray insecticides on plants that are suffering the environmental extremes or water shortage to discourage plant injury
- Always take the plant outdoors and then spray pesticides. It will minimize the exposure to chemicals in the home.
- Only use insecticides that are specifically labeled for use in the indoor environment. For example, do not use garden and yard pesticides in interior spaces.
- Do not spray aerosols closer to the plant because it will cause injury to the plant.
- When using systemic insecticides containing DiSyston, be extra careful during watering because they can be highly toxic.
Use of Alcohol to Control Houseplant Pests
Alcohol treatment is best against scale insects and mealybugs. The spray of alcohol or dabbing of alcohol with cotton swabs kills the soft-bodied insects.
However, care should be taken while applying spray because it may cause injuries to foliage and flowers. To avoid houseplants injuries, use dilutions of alcohol or apply them once a week on plants.
Insecticidal Soaps to Get Rid of Houseplant Pests
Insecticidal soaps are potassium salts of fatty acids and the most common insecticides for houseplant pests. These are consistently applied in dilution form (mix one to three parts of insecticidal soap with a liter of water) and can control spider mites and other plant pests.
Many mild dish soaps and other detergents have insecticidal properties and control snails, slugs, fungus gnats, and black flies.
Neem Oil to Get Rid of Plant Pests
Neem oil extracts neem seeds—a commonly grown tree of tropical regions. The neem oil spray interferes with insect growth and development and kills them. And it is most helpful in controlling adult fungus gnats, whiteflies, and some other houseplant pests.
The applications of neem oil are safe indoors and valuable for the rapid control of insects.
Horticultural Oils to Get Rid of Plant Pests
The spray of horticultural or mineral oils is an effective problem solver of houseplants against whiteflies, spider mites, and scale insects. Fortunately, these refined oils suffocate the insects and their eggs.
To achieve effective results, frequent sprays of these mineral oils are required. Once the problem is gone, apply these sprays once a week or after every two weeks.
Note: While applying these oils and insecticidal soaps, always cover the insects. Also, do not mix the mild soaps or dishwashers with insecticidal soaps because this mixture will burn the houseplants.
Precautions for the Use of Mineral Oils, Neem Oil, and Insecticidal Soap
- Always read each product’s label carefully, and you are treating it as mentioned on the label.
- Thoroughly apply the spray on the entire plant (covering both upper and lower surfaces of the foliage)
- If the product must be diluted in water, always dilute it before application.
- After applying these sprays on plants, keep them outdoors for direct sun exposure to dry chemicals.
- Before application of neem oil or insecticidal soap, water the plant before one or two to avoid the water stress after treatment
Early Detection of Plant Pests is Key to Control Their High Numbers
There is another best way to keep pests away from house plants: early detection. Finding plant pests at the early stages of their establishment prevents the problems of houseplant injuries.
The keep steps in early detection include:
- Thoroughly examine the houseplants before purchase
- Use a hand lens for the examination of all plant parts because many insects (spider and russet mites) are invisible to the naked eye
- Inspect the underside of leaves for larvae and eggs because many houseplant pests lay their eggs beneath leaf surfaces
- Carefully inspect the plant leaves for any discoloration and curling because these symptoms are associated with pest problems.
- Inspect the underside of leaves for spider mite webbing
- Carefully monitor the plant for honeydew and sooty mold growths because they indicate the infestations of aphids, mealybugs, whiteflies, and scale insects
- Inspect plant pots before planting
- Thoroughly disinfect the pots with bleach
- Examine the plant-soil ball for the millipede and fungus gnat larvae infestations. It is wiser to change the soil ball for healthy plant growth.
- Quarantine the newly purchased plants for at least one week, and during this period, monitor plant foliage, potting soil and stems.
- Slightly disturb or shake the plant with your hands to monitor for springtails and fungus gnats.
- Feed the houseplants with appropriate water and nutrients to avoid pests
Why Do I Have the Black Aphid Infestations on My Houseplants?
Aphids are sap-sucking insects that secrete a sticky substance called honeydew and weaken plants. The black aphids may get in-home due to the purchase of newly infected plants and through open windows.
These black aphids may also get inside spaces by attaching clothes. Once they are in, they overwinter on the underside of leaves and lay eggs. They also make it difficult for houseplant owners to get rid of them.
What Are the Most Common Houseplant Pests?
The most common houseplant pests are fungus gnat, aphids, spider mites, scale insects, root aphids, mealybugs, whiteflies, and russet mites. Among these plant pests, some suck plant juices while others chew their foliage and make holes in it.
All these pests harm houseplants and their aesthetic value. Therefore, keeping them away from various non-chemical and chemical methods from indoor plants and environments is wiser.
How Do I Get Rid of Bugs on My Houseplants?
The following methods are best to eliminate bugs on houseplants, including chemical and non-chemical.
- The first approach is prevention, which involves providing plants with good growing conditions. If the plant is healthy, there are fewer chances of getting pest infestations.
- Maintain optimum watering and nutrition conditions and remove the fallen, diseased leaves from pots.
- Spray plants with home DIY (mixture of vinegar, water, and sugar) to wash off the adult insects and larvae
- Rub plant leaves with isopropyl alcohol to remove aphids, whiteflies, scale insects, and mealybugs.
What Environmental Conditions Do Attract the Houseplant Bugs?
The moisture and nutrient-rich soils attract houseplant bugs. These bugs reproduce in these soils (lay eggs and overwinter). At the same time, the larvae feed on plant roots and leaves. The high moisture also causes the rotting of plant roots which attract larvae of most common houseplant pests.
So, to discourage houseplant bugs, always water houseplants properly and let the soil surface dry between each watering. If possible, keep plants outdoors in direct sun to dry out the larvae.
When Should I Apply Chemicals to Control Pests?
The chemical sprays should be carried out only when the non-chemical treatment is not working. The chemical spray includes contact, systemic, and microbial insecticides. These pesticides are helpful in the rapid killing of houseplant bugs. For example, imidacloprid is a systemic insecticide effective against mealybugs, soft scales, aphids, and whiteflies.
What Kills Russet Mites on Contact?
Neem oil spray is effective in the removal of adult russet mites and their larvae. It retards the growth and development of russet mites and kills them. The application of neem oil is more practical because they do not have longer persistence in the indoor environment. It also does not kill beneficial insects.
In addition to that, to control russet mites, plants are also sprayed with pyrethrum. This insecticide also kills the russet mites, but it requires the full coverage of the insect body to work correctly.
How Long Can Russet Mites Live in Soil?
Warm and dry conditions encourage the russet mite infestation. However, they proliferate in an indoor environment. And they live in soil for three weeks. The eggs that remain and overwinter in soil do not produce any particular stage.
How Long Does it Take to Kill Russet Mites?
The life cycle of russet mites is completed in seven to ten days. So this period is crucial, and effective monitoring plays a vital role in killing russet mites. During this time, spray plants with neem oil, insecticidal soap, and mineral oils at all stages of russet mites (egg, nymph, pupae, and adults). And make sure to cover the insect bodies for rapid killing of them completely.
Are Aphids Bad For Grapevines?
The grapevine aphids or grape root aphids are not true aphids. Instead, these are tiny insects similar to aphids in appearance and cause severe destruction of grapevines. These grapevine aphids are known as grape Phylloxe. This is because they turn the roots of host plants into brown and mushy. As a result, their host plant dies.
What Are the Tiny Brown Beetles in My House?
These small brown beetles are also known as drugstore beetles, and they prefer store products as their food. Unfortunately, they also infest dried fallen leaves of houseplants and infest a wide variety of indoor plants. The simplest way to get rid of these tiny brown beetles is to vacuum a dehumidifier.
Sources for Further Reading
- Colorado State University Extension. (2016, April 15). Managing Houseplant Pests – 5.595. Extension. Retrieved February 19, 2022, from https://extension.colostate.edu/topic-areas/insects/managing-houseplant-pests-5-595/
- Managing insects on indoor plants. (2020). UMN Extension. Retrieved February 19, 2022, from https://extension.umn.edu/product-and-houseplant-pests/insects-indoor-plants
Scott, J. M., & Williamson, J. (2021, September 13). Common Houseplant Insects & Related Pests | Home & Garden Information Center. Home & Garden Information Center | Clemson University, South Carolina. Retrieved February 19, 2022, from https://hgic.clemson.edu/factsheet/common-houseplant-insects-related-pests/#:%7E:text=Use%20a%20cotton%20swab%20dipped,to%20spray%20all%20plant%20surfaces.
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