How to Identify and Manage Them
The Christmas cactus is a lovely blooming succulent. For the most part, this plant is extremely easy to grow. It does well with slight periods of neglect and a good watering schedule. This plant blooms in late December, right around the holidays. If you’re hosting guests this season, you’ll want it to look healthy and pest-free!
Even the best-intended houseplant gardener can run into pest issues from time to time. Most of the time, they can be prevented with good plant care strategies. Other times, the pests have probably come indoors after your plants have had a nice summer break outdoors.
In this article, we will review nine pests you can find in Christmas cacti and how to prevent or manage them.
Aphids
If you are an outdoor gardener as well as an indoor gardener, you will likely have run into an aphid or two. These tiny pests are much more common outdoors than indoors, but if your plant has spent any time outdoors, there is a chance they have moved indoors with your plant.
You will likely see aphids on new foliar growth. These bugs like to feast on healthy and juicy foliage. You may notice yellow or deeply mottled foliage in the presence of these pests.
Aphids secrete a sticky substance called honeydew, which can attract other insects and create a breeding ground for diseases.
Aphids are typically green but can also be brown or black. These tiny insects are pear-shaped and have long antennae. You may find them on new growth.
Monitor your cactus after you bring it indoors. Apply neem oil if you believe it was previously infected. This will smother any aphid eggs that might be on the plant.
- Before any chemical applications, rinse your cactus off in your kitchen sink or outdoors with a hose. This can knock the aphids off.
- If the aphids persist, begin regular application of neem oil.
- Place a plant sticky trap in your soil. You may be able to catch a few of these pesky pests. If not, then you know you have taken care of the issue!
Fungus Gnats
Fungus gnats are pesky little flying insects, but their larvae do all the damage. It is important to control the adults to control the future population of these insects in your plant.
Fungus gnats are drawn to over-saturated soil. Good drainage is key to prevention.
The signs of fungus gnat infestations are adult fungus gnats. The plant will appear to have been grossly overwatered and suffering from root rot. This is because the larvae are nibbling on the roots, which will cut off your cactus’s ability to uptake nutrients from its soil.
These small flies resemble mosquitos. They will rarely reach ½ inch in length and are typically about ¼ of an inch long. They are silver or grey in appearance, with wings and long antennae. They linger near or in the soil.
The damage is in the roots. Above the soil line, damage will resemble that of an over-watered plant. Underneath the soil, the larvae will chew through and seriously damage roots, leaving them open to fungal or bacterial infection.
Because the damaging larvae are in the soil, it’s a good idea to quarantine your plant before bringing it home or bringing it indoors. Use yellow sticky traps in your plants. They can help catch the flying adults. A two-week quarantine will help you establish whether you have a problem and treat it.
If you officially have fungus gnats, you can begin spraying neem oil or a pyrethrin spray. A soil drench incorporating Bacillus thuringiensis var. israelensis is also effective at killing off fungus gnat larvae in the soil. Whichever method you choose, please follow the application instructions for the best results.
Mealybugs
Mealybugs are common houseplant pests. These insects are not a big deal if you catch the infestation early. They reproduce quickly, and small populations can explode before you know it. This is when you have a bigger problem on your hands.
Mealybugs thrive in warm and humid conditions, making the inside of your home a welcome spot for these bugs to feast on your Christmas cacti.
These insects will cause damage, but they are treatable. Keep your eyes peeled for fluffy spots on your plants paired with discolored leaves.
Mealybugs are small, but they appear like white fluffy masses slowly creeping along on your plants.
Damage caused by mealybugs can be discolored leaves and potential early leaf drop.
Putting your plant into quarantine before adding it to your collection is a great way to get started on the right foot.
Do repeated checkups to make sure you catch the infestation early on, making removal easier.
Start by spraying with a hose to remove any mealybugs naturally. If that doesn’t work, try using neem oil or a cotton swab dipped into a diluted rubbing alcohol spray. Both of these will help to get rid of your mealybug population.
Root Mealybugs
Similar to the mealybugs above, root mealybugs are scale insects, but these buggers live in the roots of your tropical plants.
Root mealybugs can show up in your houseplants at any time. The only requirement is moist and warm soil.
You will see a white waxy layer on the soil surface. The plant itself may wilt entirely as the insects suck the juices right out of the plant.
Since these insects live in the soil, it can be hard to detect them. Dig around around in the soil, and look for white fluffy insects just like the aboveground version.
Getting rid of these soil-dwellers can be tricky. Begin by popping your plant out of its pot and very gently removing as much soil as you can from the roots. Take extra care not to damage them. Once you have the dirt removed, discard it. Place your plant in hot, but not boiling, water. Repeat this process as needed. When you feel like you’ve gotten all of the bugs out of the roots, repot into fresh soil.
Applying systemic insecticide is a surefire way to get rid of root mealybugs. It’s best to take your plants outside while you apply this insecticide.
Scale Insects
Scale insects can be found in just about every garden. While some types of scale insects are host-specific, there is also scale that will attack just about any plant you’ve got on hand.
Scale likes warm weather. If your Christmas cactus spent the summer outdoors, monitor your plant for a few weeks after bringing it inside.
Scale insects can cause a lot of damage rather quickly. They will appear en masse and hunker down in your plant until further notice. Some plants are more resilient than others to scale damage, but a heavy infestation often kills your cactus.
Scale insects can be identified as small bumps on the surface of leaves or stems. You can remove them by using rubbing alcohol. If the underside of the bump looks like a bug, well it is.
Scale damage can look different from plant to plant. Oftentimes there is stunted growth, yellowing leaves, and leaf drop. This damage can be fatal to a plant if the scale is not controlled.
The best way to prevent scale insects is by keeping your plant healthy! Scale loves to set up shop on stressed plants.
- Keep soil healthy
- Fertilize as needed
- Water on a schedule
- Provide sufficient light
There are a few ways to control scale insects:
- Keep your plant healthy
- Remove damaged plant tissue
- Use a cotton swab dipped in isopropyl alcohol to force the scale insects to release from the plant, then dispose of them
- Use neem or horticultural oils
- Lastly, use a systemic insecticide for houseplants
Spider Mites
Spider mites are relatively common insects. These microscopic insects resemble spiders. They have eight legs. The females have black spots on their backs.
Spider mites can show up at any point. They could come in from outside or hop from one houseplant to the next.
Symptoms will begin as a yellow stippling to your Christmas cacti’s leaves and progress from there, leading to bronze leaves and potentially plant death if you do not try to eradicate the spider mites.
Spider mites are nearly invisible to the naked eye. You may notice the webbing they produce to protect themselves or the damage they leave in their wake.
The classic damage is yellow or bronze-colored stippling throughout the leaves.
The easiest and best way to prevent spider mites from infesting your plant is to take good care of it. Ensure that your plant is getting the right amount of water and light. Spider mites love a stressed plant, so do your best to avoid that!
Dusting your plants or washing them off with your kitchen faucet or outdoor hose is a great way to keep the mite population in check. In addition to cultural practices, applying neem regularly will help knock back spider mite populations.
Springtails
Springtails are tiny insects that are highly attracted to moisture. Growing to only about 1/8th of an inch long, these tiny insects may be dark in color or white.
Springtails appear in areas of high moisture, such as bathrooms or very overwatered soil.
Springtails are not necessarily damaging but are a warning sign that you could have a fungal issue, most likely root rot.
Most springtails are dark brown or black, but you may see some white varieties as well.
They do not do much damage to your plant, but signal another underlying problem.
Be mindful of your watering. Christmas cacti should only be watered every one to two weeks, depending on the amount of light it receives and the humidity levels in your home. These insects love overwatered plants, so keep the soil on the dryer side.
Unfortunately, pesticides are not effective on springtails. You can remove springtails by hand if there is only a small amount
Thrips
Thrips are very common insects in all aspects of gardening, from agriculture to our houseplants and everything in between.
Typically, you will have thrips in your home if your plant was previously infested or had other infested plants. This could mean that you brought them home from the garden center, or your Christmas cactus could have become a home for thrips while outdoors.
Thrips can be difficult to spot with the naked eye. Common signs of damage are a silvery sheen to the leaves and some oddly colored stippling. If you notice this within your plant but don’t see any insects, place a white sheet of paper under the plant and give the pot a shake. They will fall onto the paper if they are living in your plant.
These insects are long, slender, and dark in color. Their larvae are small and will be yellow or green.
Stunted growth and curling leaves are signs of thrips damage as well as a silvery appearance to your leaves.
Sticky traps as well as good gardening habits, can keep track of the presence of these insects.
Thrips are well controlled outdoors by natural predators such as parasitic wasps. Unfortunately, releasing parasitic wasps indoors isn’t a great idea. Luckily, neem and insecticidal soaps work well at getting rid of thrips. Be sure to follow application rates and a good schedule to keep these insects away. Prune away any infected foliage.
Whiteflies
Whiteflies are very common plant pests, especially indoors or in a greenhouse. Their small size makes it easy for them to move indoors and out.
Whitefly adults will lay eggs toward the end of spring. These eggs hatch in about two weeks, and their larval stage can last about a week before the adult emerges. The adults can hang around for a few months, preparing to lay eggs.
Whiteflies have sucking mouthparts that they use to suck the plant juices out of your Christmas cactus. These insects excrete honeydew, a sticky liquid that can attract ants and mold issues. Because whiteflies can cause other issues, other than just eating the plant, this is an insect that should be controlled.
Adult white flies are extremely small and hard to see. They are white and resemble tiny moths. Their eggs are found on the underside of leaves, typically in concentric circles.
Whiteflies suck out the juice of the plant. This can leave the plant appearing weak and will cause the plant to produce misshaped growth. You may notice yellow, dehydrated leaves as well as dropping leaves.
Quarantine the new plant for a week or two to monitor for a whitefly infestation before adding it to your other plants. You may also opt to spray with neem as a preventative measure. This will prevent adults from laying eggs on your plant, and it can also help control eggs that may already exist on the plant.
Before you spray anything, take the plant to your kitchen sink and spray it down. Sometimes this is enough to get rid of your whitefly problem.
Gardeners have had success using a handheld vacuum to remove any eggs and to catch those fluttering adults. Be careful not to damage your plant!
You may also opt for neem or horticultural oil. These are both easily found at your garden center. Follow the application instructions to be safe!
Final Thoughts
When it comes to keeping your Christmas cactus pest-free, the key is keeping your plant healthy. Following good plant care guidelines makes you less likely to run into pest issues. This is partly because pests love stressed plants, but it is also because you will spend more time up close and personal with your plant and notice if something seems a bit off. Keep your chin up. You can keep those Christmas cacti pest-free and healthy!
