Exterminating Pests on Your Succulents and Cacti
Us succulent and cacti owners have it pretty easy – there are relatively few pests that prey on succulents and cacti. We’re extra lucky that our plants are incredibly tough; they can endure infestations for quite a while and can withstand harsh insecticide treatments.
When an infestation happens, don’t panic! By identifying the pest early and treating it promptly, you can almost always guarantee the survival of your beloved cacti.
But before we start, let’s talk about how to prevent pests from popping up in the first place!
An ounce of prevention is worth a pound of cure! Here are a few easy ways to mitigate the spread of pests and make your succulents unappealing.
Whenever you get a new plant you should immediately quarantine it for at least two weeks. Position it at least two yards away from the nearest plant (but be sure it has enough light). This will prevent any existing pests from spreading to other plants.
Although it’s rare to receive plants that are already infested, it happens occasionally (especially if you buy plants at big box stores). Sometimes the soil carries eggs of pests and those can hatch at any time.
Almost all pests thrive in moist, dark, warm environments. Keep your plant is a dry, sunny place with plenty of airflow and you’ll rarely have problems with pests. After all, that’s the environment that succulents like anyway. Win-win!
Be careful not to water too frequently, either. Make sure your soil is fast-draining and loose so it dries out rapidly.
Keeping your plants’ pots neat and tidy will also help keep pests at bay. Trim and prune regularly and remove dead plant matter from the pot.
Leaving dead leaves in there won’t improve the quality of the soil, it’ll just allow pests a place to hide and food for their larvae! Not to mention decomposing material holds a lot of moisture, which is the opposite of what we want.
Types of Succulent and Cacti Pests
While there are more pests that could potentially infect your succulents, the vast majority of infestations will be from one of these four bugs.
Mealybugs are fuzzy, white insects that are usually found in large groups. They have a cottony appearance and are quite distinct, though at a distance you might mistake them for a spiderweb.
They love to inhabit crevices and other hidden, protected place. Examine places where leaves meet the stem of your succulents, that’s a favorite spot.
Fortunately, mealybugs are very easy to deal with. If the infestation isn’t too bad, you can simply unpot the succulent and hose it off thoroughly with a strong stream of water. That should be enough to dislodge all of the mealybugs.
Some species lay their eggs in the soil, so you’ll want to repot the plant in fresh dirt. If you’re concerned about whether your soil is infected, you can bake it in an oven at 200 degrees for a couple hours to kill anything that might be hiding in it.
If water doesn’t do the trick, or you’re not willing to repot the plant, apply rubbing alcohol to the parts of the plant that are infested. Regular 70% isopropyl alcohol will kill the insects immediately, but your succulent won’t be bothered at all. Try putting alcohol in a spray bottle and give the plant a liberal squirt.
Scale are a bit tougher to deal with, and also more difficult to notice.
Scale appear as round or oval bumps on the skin of the plant. They bumps are quite small, no more than a centimeter or so in length, and are always dark-colored.
The reason they’re called scale should be immediately apparent – these insects are covered by a hard, smooth shell. When they reach their adult stage, they pick a spot (often along the stem) and dig in, never moving again. They’re nearly invulnerable to predators and also fairly resistant to chemical treatments.
They tend to spread pretty slowly, though. If you see a few of them on your plant, they can be pretty easily removed by scraping with your fingernail or a blade. If there are more than a few, you’ll want to use a powerful insecticide.
Neem oil is your best bet. Be sure to read the instructions carefully, as neem oil is often sold as an extract and needs to be diluted before use. Also keep in mind that, as an oil, it could cause sunburns if the oil is on the plant and in strong, direct light.
For that reason, it’s best to apply neem oil at night. That also helps prevent beneficial bugs, which are mostly active during the day, from being caught in the crossfire.
Spider mites are particularly resilient because they breed very quickly and can overwinter in the soil. Unlike most pests, they thrive in the same conditions that succulents do – hot and dry is their preferred climate.
Spider mites are very easily identifiable by their tangled, wispy cobwebs they spin over themselves for protection from predators. They vary in color from brown to black to red, and many of them are so small you’d need a magnifying glass to see them. They hang out almost exclusively on the undersides of leaves, so check for webs there.
Although they puncture leaves to suck the juices out, the damage is relatively slow-paced. A plant would have to be totally inundated with spider mites to be in real danger. Look for sporadic patches of yellow, brown, or gray scarring on leaves – that’s probably spider mites.
First step to getting rid of them is using strong water to wash away their protective web covering. Then, apply neem oil like you would with scale. The isopropyl alcohol treatment also works well. Another option is to use insecticidal soap, which you can either buy or make yourself by adding a few drops of dishwashing soap to a quart of water; apply via a spray bottle generously.
Fungus gnats are really just an annoyance, hardly even a pest. They’re ubiquitous though, and worth mentioning.
They are more or less like fruit flies in every regard. Maybe a bit smaller. They rest on the leaves of your plants and will sometimes take off in a swarm when you brush by them.
The adult gnats you see flying around are very short-lived and don’t even eat at all. They lay eggs in moist soil. The eggs hatch into larvae which mostly just eat decomposing material, but will munch on fresh, tender roots if given the opportunity.
While fungus gnats are not very dangerous to your succulents and cacti themselves, they are an indicator that your plant is too wet. Either give the plant more time to dry out between waterings or replace the soil with a looser, fast-draining variety.
Fungus gnats are extremely easy to get rid of. If you let your soil dry out completely (no water for two weeks or so), the eggs and larvae will shrivel up and the adults will eventually die. The adults are exceptionally week flyers, so if you position a fan to blow over the plant they won’t be able to return and lay eggs.
For a more immediate solution, water your plant with an alcohol or insecticidal soap solution and soak the soil thoroughly.
That’s the quick-and-dirty guide to getting rid of pests on your succulents and cacti! Are there any other pests you want information about? Do you need clarification? Let us know in the comments below!