🌵Cactus Care 101🌵: Cactus Pests, Oh No!
Pests are a part of plant life, and as a gardener or plant enthusiast, you will run across some of them eventually. The most important thing to remember when dealing with cactus pests is that everyone will deal with them. Everyone also makes mistakes with their plants, and it’s completely normal to be a little shaky in the beginning. It happens to the best of us, and these are a few tips to take out the pests common in cacti.
A good offense against pests is a good defense. The more preventative measures you do, the less likely you’ll have any major problems.
- Check your plants frequently, you’ll be more likely to notice something is wrong the more aware of your plants you are.
- Remove any dead leaves or dead flowers: The less dead or decaying matter, the less likely pests will take up residence.
- Keep your plant pots and the space where you keep your plants clean.
- Quarantine any new plants for a sufficient amount of time and repot them into fresh soil.
The 3 Most Common Cactus Pests:
Cactus pests are mostly the same for all ornamentals, but they do have a few that prefer to prey on them due to their succulent nature. This is by no means a comprehensive list, but the odds are if you have an infestation, it’s one of the three pests listed below.
As a disclaimer, if you believe you cannot effectively treat a plant and are worried it will infect your entire collection if you keep it, feel free to throw it away. I’m not judging you for it, and most seasoned plant keepers won’t either. Sometimes it’s just not worth the risk or effort.
The Mealybug is also known as Mealies. Scale is the mealybug’s cousin, with the symptoms and treatment for both of them being almost the same. They are probably the most infamous pests of cacti and succulents, and are very difficult to eradicate once they’ve taken hold of a collection.
Mealybugs - image credit homyden.com
Scale - image credit lrgarden.com
Mealies and Scale feed on the juices of cacti, causing little scars where they puncture through the body of the plant to suck its juices.
For Mealybugs, white nests and clumps of insects you will see on cacti are the females of the species, the males are tiny little flies that will fly around and mate with them.
Sometimes mealybugs will burrow into the soil and latch on to the roots of the plant. They turn a pink color and are very difficult to pick out if you’re looking at a root system covered in dirt. These are called root mealies. Mealybugs also have a waterproof waxy coating on them that gives them their white fuzz, making it difficult for some pesticides to penetrate and kill them.
For Scale, they actually do look like little brown scales on your plant, and don’t move much as adults. The juveniles however are extremely small and will crawl around your plant until they find a good place to settle.
Scale can be armored or soft bodied, which can make it difficult for topical treatments to kill them.
Signs of Mealies and Scale:
- White Fuzz, Or Strange White Cotton Spots/ Brown Flecks or “Scales”-On fuzzy cacti, mealies can be difficult to spot, look for irregular white patches that spread. Scale is easier to see but can also hide at the base of your plant.
- Honey Dew - Sticky globs of sap may be found on your plant that are produced by the bugs. They can harden into a resin.
- Sooty Mold - Black sooty mold can grow on your plant due to the presence of the sticky sap mealybugs and scale produce.
- The Plant Wilting Or Failing To Thrive - If you see no signs of mealies and your plant is still wilting or off color, unpot it and check the roots. Root mealies will be pink versions of their white-bodied above ground siblings. Scale can also be hard to spot, so use a magnifying glass to get a closer look if you’re not sure.
- Immediately Isolate Your Plant - I cannot cannot cannot stress this enough. Mealies can crawl, mealies can move, mealies can hide under your pots and in the cracks of your windowsills, mealies can infect your entire collection, easily. Scale bugs as adults, rarely move, but they can reproduce quickly and are harder to eradicate, especially if they are the armored kind. Isolate any infected plants from your other plants. Proper isolation can make mealies or scale a simple frustration instead of an absolute nightmare.
- Alcohol Swaps - A q-tip dipped in rubbing alcohol can be directly applied to each bug you can find on your plant. It kills them instantly. Go over the whole plant and re do this for several days until you stop seeing them.
- Insecticidal Soap - Also known as potassium soap. Insecticidal soap destroys the white waxy coating on mealybugs and smothers them.
- Neem Oil - Sprayed on the plant similar to insecticidal soap.
- Systemic Insecticides - Controversial and should be used as a last resort. Mostly used for root mealies and bad scale/mealybug infestations. Follow the instructions very closely as these can be very toxic. If you have root mealies, systemics are unfortunately the only effective treatment for them.
- Alcohol Spray - Clean off whatever shelf or planter your plant was on, and spray it down completely with rubbing alcohol. Try to get in the cracks and places you normally can’t reach. Mealies can hide all around your plants.
- Repot the Plant - Mealies and baby scale can hide in the soil of your pots. It’s best to get rid of it completely and start again with a sterilized soil.
- After a year, consider your plants safe again, but remain vigilant. Spray all your plants with insecticidal soap every once and a while. I usually give my plants a good soaking with it before and after dormancy.
Disclaimer: Use caution when using soap or oils and exposing your plants to light, as they can cause chemical burns in sunlight!
Red Spider Mites are very small red mites that cluster in groups and can do a lot of damage to cacti. They are tiny red dots, and you’d probably need some help to see them individually with a magnifying glass or phone flashlight.
Red spider mites - image credit cactusnursery.co.uk
Signs of Red Spider Mites:
- Webs - you will see webbing similar to a spider’s all over your plants, with no spiders to be found.
- Scarring of the plant - your plant will have white or yellow patches of scar tissue on it, especially over new growth
- Tiny red dots that move - these guys are small, but you can see them with the naked eye. They also like to clump in larger red clumps.
- Immediate Isolation from the rest of your collection. It would be wise to give your entire collection a spraying with insecticidal soap or miticide as well.
- Spider mites hate to be wet. Adjust the environment to be less dry or drown them with a insecticidal soap or miticide. As a disclaimer, most systemic insecticides do not work on spider mites, so make sure whatever treatment you use actually is effective.
- Neem Oil is an effective treatment against spider mites, just be careful about placing your plants in full sun after using it.
- Continue spraying until the red patches and webs have vanished and no new scarring occurs. Continue to spray for a few weeks afterwards and keep a close eye on the plant to make sure the mites haven’t returned.
Good luck cactus friends!
I know I did this before the sick cacti post, that one is coming up next!
Link To All Cactus Care 101 Posts Here!