White Bugs on Plants: Identification, Damage and Control

As people became more aware of the plants that I was growing in my home, I noticed I would often get the question, “How do you deal with all the insects?”

“All the insects????” I thought. “What on earth do they mean?” I couldnt quite pinpoint the root of their question. Did they assume that benign insects were just generally attracted to flower and foliage—or were they insinuating that I had an outbreak of insect pests? If the latter, I must admit that for the better part of six years I was blissfully unaware of any pesky insects in my home. Not because Im out of tune with plant and bug (most friends know that Ive been raising insects since I was 9 years old and ended up studying entomology in college), but largely because my plants didnt have any noticeable pests.

All of that changed in 2016 when I began growing food in my home. I had converted my closet into a vegetable garden as an experiment and within weeks, the pest numbers exploded. I noticed scale, including mealybugs; whiteflies; thrips; and even the fungus gnat, (the latter which is more annoying than pest-like). As a prolific gardener in an indoor, closed environment, I didnt have any desire to toss out plants or spray toxic insecticides indoors, so I opted for integrated pest management and natural techniques, which Ill go over a little bit here and more in depth in a subsequent post. However, I wanted to use this time to go over some of the common pests that you may eventually get on your houseplants, and simple ways to prevent infestation from the onset.

The list of seven insects and mites are by no means an exhaustive list of houseplant pests, but they are the most typical ones that youll likely see in the home.

Scale are primarily immobile insects that stick themselves to stems and leaves. They come in two families: Coccidae and Diaspididae. The brown soft scale (Coccus hesperidum L.) shown here is a common houseplant and greenhouse pest.

Common brown scale (Coccidae and Diaspididae families) The first time I noticed a scale insect was on a jasmine plant that I had purchased at the farmers market. I didnt see the insect at first, but I did notice that some of the bottom leaves of the plant were shiny and sticky. Upon closer inspection, I noticed brown nubs stuck to the woody stem and underside of leaves, closest to the central vein. This was scale.

There are different varieties of scale but by far the most common is the brown soft scale (Coccus hesperidum L.). They are rather inconspicuous—and dont look like a typical insect—unless you know what to look out for. Firstly, theyre ovate, only about 3-4 mm long and about half as wide. They can range in color, but are most often brownish in appearance (hence the name), but Ive also seen them in shades of yellow, amber, and even olivaceous. Theyre called “scales” largely due to their scale-like appearance on a plant, due to waxy or armored coverings. They are often seen in clumps along a stem, sucking away at the plants juices with their spiky mouthpart.

They are only mobile when they are born. Soft scales, which are just one of the groups of scale insects, can reproduce both sexually or parthenogenetically, which means that they can produce young without fertilization. Quite unique in the insect world, the female scales are ovoviviparous, which means they give to birth to living young by hatching the eggs while they are still in their mother. This is the same in Madagascar hissing cockroaches, which are not a plant pest, but an insect that I raise, and Ill be the first to say that it can be shocking that one day youll have 2 cockroaches and the next day 20X that amount. Same goes for the scale insects. I say this only because you cant really get rid of the eggs unless you get rid of the adults. Once the young, which are called “crawlers” are born, theyll disperse along the plant, find a place they like (usually around some new growth), and literally plant themselves there for the remainder of the time—reaching maturity at around 65 days.

Scale can be a real problem indoors because quite frankly, they have a good temperature year round, which means theyll likely reproduce around the clock. Good news, however, is that scale are, as I shared, relatively immobile, so if they are contained to one plant, then you can control them. Most people choose to discard the plant. Though it was slightly stunted in growth, I decided to keep my jasmine to see if I could revive it. First, homemade soap sprays arent that effective on scale, partially because the scale on the outside of the insect acts like a shield. Youd want to get it under the cap of the insect.

What I did was as follows:

1. Place a plastic bag or some covering around the soil of your plant. This prevents any scale from falling into your soil.

2. Get a natural, rosemary-based insecticidal soap. Spray this on the plant so its nice and soapy.

3. Run your fingers along the stems and plant leaves, turning up the scale with your fingernails. If you dont want to touch the insects, you can use an old toothbrush or even a toothpick, but I feel as if I have more control and accuracy with my fingernails. You may notice some scale fall onto the plastic bags; pick them up and discard them. Really be sure to look over the entire plant. My jasmine had a woody stem and the scale looked like part of the stem, so dont be fooled! If helpful, get a pocket magnifier to look over the plant, including the creases of where the leaf meets the stem.

4. After youve sufficiently soaped and scraped the plant, give it a good, sharp spray with your hose or your shower. Youll want to get all the soap off the plant so it doesnt affect growth. Keeping a plant strong, healthy and growing, can often keep insects at bay.

5. Check the plant again for the next three days, making sure that you hadnt missed any scales. If you did, you can repeat steps 1-4. Check again once a week for the two months, just to make certain you got all the little buggers.

Mealybugs are a type of cottony, mobile scale that often can be seen in clumps on your houseplants. They are generalists, and Ive particularly found them on everything from my potato plants, succulents, Stromanthe and Plerandra.

Mealybugs (Pseudococcidae families) Im not quite sure how mealybugs first got into my home, but I first noticed them on my potato plants that I was growing in my closet garden. Potatoes, particularly the leaves and stems, grow incredibly fast, so I was monitoring them pretty closely. I first planted the potatoes from ones that I purchased in the farmers market and that started growing “eyes”. Interesting enough, I had more potatoes that began growing eyes in my fruit basket, and mealybugs would just “show up” on them. Still to this day Im befuddled by their spontaneous generation.

Mealybugs are an unarmored scale insect, and I personally think they are more difficult to control than the common brown scale. This is for a few reasons. First is the most obvious: mealybugs move. Though its slow movement, if any plant is touching another, there is a chance the mealybug will hitch a ride on a new leaf and spread. Secondly, though their soft, cottony white appearance is quite obvious on a plant, they have a tendency to hide out in the damnedest of places, like the crotch of a plant or in a leaf that has yet to unfurl. Additionally, they have waxy secretions, giving them their cotton-like appearance, which can serve as some basic protection. And lastly, they breed like rabbits of the insect world. Females can deposit around 600 eggs in loose cottony masses, often on the underside of leaves or along stems. The early instars will hatch in about a week and this often causes a population explosion.

As such, its important to get mealybug populations in control. Some will toss out a plant completely, but I did no such thing. Instead I did a three-pronged effort, involving the release of two beneficial insects—the green lacewing (Chrysoperla carnea) and highly effective, aptly named mealybug destroyer (Cryptolaemus montrouzieri), and also spot treatment using a q-tip and isopropyl alcohol. Dabbing the alcohol directly onto the mealybugs will easily kill them on the spot, but the upside to releasing the beneficial insects is that the insects can often get to places in a plant that you often cannot get, so I believe both methods—at least for me—have worked the best.

Aphids are another plant-sucking insect that often congregate in large numbers. I most often see them on my herbs and I take enjoyment in squishing them between my fingers, since they are full of plant juice. No wonder why some ants like to harvest the sweet goodness coming out of these globulous insects.

Aphids (Aphidoidea superfamily, Aphididae family) Aphids may very well be the most commonly known unwanted houseplant pests. However, Ive only ever seen aphids on the food crops that I grow in my home and never on my tropical houseplants. It may very well be a matter of preference of them, but I think what theyre really looking for is that gooey sap that they get from the plant by piercing it with their mouthparts. They also exude a sticky, sweet honeydew from their rear, which often attracts other pests, like ants—or provides a medium for sooty mold to grow on, which essentially spells disaster for a plant, particularly if its fruiting.

Aphids are a soft-bodied insect, so theyre very easy to squish between your fingers, which I typically do. Like scales, aphids are also viviparous, which means they give birth to live young. Aphids are born wingless, but if you see an aphid with wings, its a signal that the colony got too crowded and they are looking for a new houseplant for which to feed.

The best way to get rid of aphids naturally is as follows: on a warm day, early in the morning take your infected houseplant outside and spray it vigorously with a hose. Be careful not to break the plant if its delicate or newly growing. This can be done by spraying short, strong bursts. This should knock down the aphid population naturally. Once youre finished, inspect the plant and crush any remaining ones with your fingers. Repeatedly do the hose-spray method for another few days until you see everything is under control. If you find aphids keep on coming back despite your best hosing efforts, I would then encourage bringing in some beneficial insects, particularly green lacewing larvae or ladybird larvae.

Whiteflies (Trialeurodes vaporariorum) closely resemble tiny white moths, but they are closely related to aphids and scales. Like aphids, they produce honeydew from sucking plant juices, which can then attract sooty mold, which can further harm plants.

Common whitefly (Trialeurodes vaporariorum) At first whiteflies, which are more closely related to aphids and scale, can be mistaken for little white moths or even mealybugs. Unlike their fellow pesky counterparts, they will easily take flight if you disturb them. I first noticed whiteflies in my home when I started growing potatoes indoors (I mean seriously, potatoes indoors brought every pest imaginable!). Whiteflies are more or less generalists when it comes to plants. I noticed that they first were congregated in small numbers on potatoes, but they soon started to alight on my elephant ear plants, which were nearby.

Adults will lay eggs while they are eating (efficient little beasts, arent they?). Eggs will hatch in less than a week and then their nymphs, similarly to scale, will crawl a short distance, plant themselves, and suck the plant until they go into a resting stage at about the 3 week point. In about four, maybe five weeks, they begin to emerge as adults and the process repeats. As indicated, both the nymphs and adults of the whitefly use their mouthparts to suck juices from plants, which can cause leaves to yellow and fall off prematurely. Additionally, whiteflies, like aphids, exude honeydew, which becomes an attractant for sooty mold. If you allow whiteflies to multiply, then they can attack your plant enough to weaken it.

Whiteflies are attracted to the color yellow, so the best way to catch them is by having yellow sticky traps, blasting the leaves with short bursts of water from a hose, and also introducing a beneficial insect, like a green lacewing, ladybird beetle, or whitefly parasite (Encarsia formosa). All three techniques are highly recommended, in that order.

Red spider mites (Tetranychus sp.) Mites are technically not insects but they, like insects, are Arthropods. They are probably some of the most feared of the common household insect pests, largely because they are so difficult to get rid of.

Spider mites are nearly naked to the eye. You often need a magnifying lens to spot them, or you may just notice a reddish film across the bottom of the leaves, some webbing, or even some leaf damage, which usually results in reddish-brown spots on the leaf.

Earlier in the year I was gifted an Alocasia micholitaiana Frydek, which is a gorgeous velvety green alocasia. I typically always check my houseplants before bringing them indoors, which is a proactive way to make sure no pesky insects are in tow, but you cant always rely on eyesight. Within about three weeks, I noticed some webbing and the start of brown dots on some of the mature leaves. Before mites could spread to the other plants, I took the Alocasia and washed it thoroughly in the shower and made sure the humidifier was on daily. Mites prefer dry conditions, so keeping the air humid and the plant on the wet side (something an Alocasia prefers anyway), was able to save the plant, although it still bears the battle wounds of the mites.

Spider mites also have a range of natural predators, including other mites like Phytoseiulus sp. and generalist predators like minute pirate bugs and lacewing larvae.

Fungus gnats (Bradysia sp.) Im including fungus gnats as a common houseplant pest, only because they are common and more of an annoyance to people versus plants. Fungus gnats look similar to fruit flies, and are often mistaken as such. They are pretty feeble fliers and can often be seen circling around soil, particularly if its fresh, damp compost. Their larvae, which are really the more cause for concern here, prefer to feed on fungi in the soil, which you can only get in moist conditions. They technically can eat plant material, but if the fungi levels are high, they often wont.

I ended up getting quite a few fungus gnats when I started to grow microgreens in a nice bed of compost. The adult gnats will often hang around the soil because thats where they like to lay eggs, but adults are harmless. I basically got some BTI, or Bacillus thuringiensis, which is a natural and safe bacteria that you can sprinkle in the soil and some yellow sticky traps to catch the adults. The problem was solved within three days. Additionally, you can bring in a natural fungus gnat predator, such as Stratiolaelaps scimitus, which is a type of mite.

Thrips (Order: Thysanoptera) Thrips are technically a less common insect pest, but Ive found that they are most prevalent in my household. I believe they first came into my home through either my herbs or one of my friends plants, and they quickly spread, as thrips are typically generalists, puncturing the outer layer of a plant and creating a silvery discoloration on the plant leaf. Youll also notice tiny little bits of black frass, which is a nice way of saying “insect poop”. One of my most prized possessions, an African blue basil (Ocimum kilimandscharicum × basilicum), which is particularly hardy and difficult to find, had been almost fully ravaged by thrips. I had saved a couple cuttings, which have now almost entirely bounced back thanks to the help of some natural predators, including Thrips Predators (Neoseiulus cucumeris) and Minute Pirate Bugs (Orius insidiosus), which I released in tandem with much success. Additionally, adult thrips are attracted to the color blue, so you can also affix blue sticky traps around your plants to curtail the population.

When you first bring home a houseplant, you may want to take a few precautions to make sure that it has no pests that will spread to your other plants. Pictured here, an Alocasia reginula.

How to Kill Mealybugs INSTANTLY ☠️ Easy DIY Solution

FAQ

How do I get rid of little white bugs in my plants?

For smaller infestations, soak a cotton ball in rubbing alcohol and wipe down every inch of the plant. Alcohol only kills the bugs by direct contact, so you may need to do a few applications. After you feel like the population is sufficiently taken care of, rinse the plant a few times with water.

How do you get rid of mealybugs?

• Rubbing Alcohol:

  • Soak a cotton swab or cloth in 70% isopropyl alcohol and wipe off mealybugs and their waxy coverings. 

  • Be cautious not to get alcohol on the leaves, as it can cause damage. 

  • Repeat treatment weekly until the infestation is gone. 

• Insecticidal Soap:

  • Mix a mild liquid soap (not detergent) with water and spray the plant, paying close attention to infested areas. 

  • Insecticidal soap disrupts the mealybug’s cell membrane, leading to their death. 

  • Repeat applications every few days as needed. 

• Neem Oil:

  • Neem oil is a natural insecticide that can kill mealybugs on contact. 

  • Apply neem oil to leaves and stems, but be cautious when pollinators are present. 

  • Mix neem oil with water and a small amount of soap to help it spread. 

• Systemic Insecticides:

  • Consider using a systemic insecticide, which is absorbed by the plant and kills mealybugs as they feed. 

  • Follow the instructions on the product label carefully. 

• Isolate Infested Plants:

  • Isolate infested plants to prevent mealybugs from spreading to other plants. 

  • This allows you to focus on treating the affected plant and minimizes the risk of a larger infestation. 

• Pruning:

  • If only a few leaves or stems are affected, you can prune them off and dispose of them properly. 

• Cleanliness:

  • Keep leaves clean by removing debris and excess moisture, which can attract mealybugs. 

• White Oil:

  • White oil is an insecticide spray that works by blocking the breathing pores of insects, causing suffocation and death. 

  • It is effective in controlling aphids, scale, mealybugs, mites, and other pests. 

• Mealybug Traps: 

  • Use mealybug traps to catch and kill mealybugs. 

• Disposal:

  • If plants are heavily infested, it may be best to discard them to prevent the spread of mealybugs. 

• Monterey Fruit Tree Spray Plus:

  • This spray provides quick and complete control of insects, including mealybugs. 

  • It works to flush insects out of their hiding spots. 

Are white bugs on plants bad?

White mites can cause damage to plants. When they feed, they weaken plants and stunt their growth. The most common species of white mite, the citrus mealybug, injects a toxin into the plant when it eats. This toxin can lead to plant malformation, making the citrus mealybug a significant culprit to overall plant damage.

What is the best spray for mealybugs?

• Products highlighted as ‘Overall Pick’ are: …
• Bonide Captain Jack’s Neem Oil, 32 oz Ready-to-Use Spray, Multi-Purpose Fungicide, Insecticide and Miticide for Organic Gardening. …
• Bonide Systemic Houseplant Insect Control, 8 oz Ready-to-Use Granules for Indoors and Outdoors, Protects Plants from Insects.