Common Pests & Diseases

No one wants to witness their beloved succulents deal with annoying pests or fungal diseases. But unfortunately succulents do develop issues from time to time and we need to be equipped to get them through the tough times as quickly as possible. This guide will list out some of the most common pests and diseases faced by succulents and cacti as well as how to treat them.


MEALYBUGS

Mealybugs on the stem of a plant. Photo via Planet Natural

Mealybugs are the tiny fuzzy white substances you see crawling on the stems of your plant. If left ignored, the mealybugs can spread and affect many different parts of the plant, causing it to slowly wither and eventually die. Mealybugs are one of the most common pest problems for succulents and a stubborn one that requires a long and thorough fight to get rid of them. You should get alert when ants start crowding your plant area as ants like the sweet water discharged by mealybugs. Another sign of your plants being infected is when they start looking unhealthy for no obvious reason (with adequate light and water). To avoid this mealybugs issue, keep your plant area dry, clean, and free of rotting leaves or flowers.


Treatment of Mealybugs

  • Quarantine the infected plants by moving them away from other plants. Inspect the healthy plants to see if they have any signs of mealybugs.
  • Prepare to clean your infected plants by taking the plant out of the pot and rinsing them under a strong stream of water. Clean the pot in hot soapy water. Letting the plant and pot dry then replant with new soil. Throw away the old soil because there might still be mealybug eggs left in there. 
  • Use either rubbing alcohol (isopropyl alcohol) or neem oil and dish soap mixture to spray the whole infected plant. Or you could use a Q-tip to paint-brush any spot with mealybugs. If you use rubbing alcohol, make sure you don’t put the plant out in full sun for a few hours since it may get burnt.
  • Check your plant and repeat the steps for a few days to see if there are any mealybugs left. Then spray again once a week for preventive measure. If you don’t see mealy bugs reappearing after a few weeks of spraying, put the plant back to its original spot, and keep checking every 3 weeks.


MICE

If you grow your succulents outdoors, you should worry about the possibility of rodents attacking your plants. Mice tend to take a bite out of your succulents or break them into small pieces. As a result, your plants can be mangled and disfigured after one night serving as food for mice.

How to get rid of mice

You can set up mouse traps near the walls of your garden. There are various options to choose from: live traps that catch the rats alive, conventional traps that kill the rats, or some poisonous baits. You can also use some wire mesh to cover your succulents if you don’t want to use lethal methods to keep rodents away, though it’s not the best in terms of the aesthetic aspect. Bringing a cat into the scene might also be an effective way to scare off rats.


RED SPIDER MITES



Photo via israel21c.org

Red spider mites are tiny red mites that leave a silky web that looks like a spider web on the plants. The spider mites are extremely tiny and you might even need a magnifying glass to be able to see them. You need to verify whether the web you see on your plants belongs to a real spider or red spider mites. If it is from spider mites, you will notice the appearance of brown spots on the plants and the new growth also turning brown. If left ignored, red spider mites will continue to eat the entire outer layer of your succulents, after this point it might be hard for the plants to survive.

Treatment of Red Spider Mites

  • Quarantine the infected plants immediately by moving them away from other plants. Inspect other healthy plants with a magnifying glass to see if they have any signs of red spider mites.
  • Red spider mites thrive in hot dry conditions and do not enjoy humid environments, so watering and spraying your succulents can be effective in deterring mite attacks.
  • Purchase some miticide, which is a chemical pesticide that specifically targets plant mites, to spray on your succulents for a few days. Check to see if there are any red mites left then spray again once a week for preventive measure. If you don’t see red mites reappearing after a few weeks of spraying, put the plant back to its original spot, and keep checking every 3 weeks.
  • If you live in areas with hot weather, the high temperature will cause the mites to reproduce more rapidly. Therefore your plants will need more frequent treatment with the miticide. Make sure you don’t put the plants out in direct full sun for a few weeks after treatment.


SCALE 


Scales refer to species of insects that look like flat or slightly mounded waxy, brown scales on the leaves and stems of the plant. The insects hide under the protective scale feeds on the plant sap and can transmit virus diseases to other plants. The protective covering strongly attaches to the plant tissue so it can leave a scar behind when you remove a scale insect from the plant. Scale insects reproduce rapidly and can cover the entire surface of a succulent in a couple of days, especially on the new growth parts of the plant.


Scale insects on succulents. Photo via Sublime Succulents

Treatment of Scale

  • Use your fingers, a small tongs, tweezers, or a water hose to remove the scales from the plant as soon as you see it. Be careful not to damage your plant while you do it.
  • To prevent their return, use a systemic insecticidal spray every week for several weeks. This solution makes the plant poisonous to the scale insects.


SNAILS


Snails can be found on the side of your plant containers or hidden under a fleshy succulent or even spiky cacti. They can be quite destructive if they come in large numbers to eat the flower buds, ingest the tender new growth of your plants or scrape off large chunks of tissue from the plant body. It is easy to detect if snails have visited your garden last night: once the snails move past your plants, they leave a slime trail behind, which dries out and glitters when seen in daylight.


Photo Credit: debraleebaldwin.com

Treatment of Snails

  • You can handpick these snails when you find one near your garden or plants. Check carefully underneath your pots as well as any shady outdoor areas to make sure none is left.
  • If a large number of snails are attacking your plants, use a snail bait to get rid of them.
  • Snails can come back and repeated treatment is necessary especially when the weather is warm and humid.

APHIDS


Aphids are those species of greenfly and blackfly that can reproduce very quickly and commonly seen on garden plants. They feed on the plant sap and produce sweet honeydew which might encourage black mould. Aphids are often found on the flowers, flower buds, and tender new growth of succulents and cacti. You should worry about aphids affecting your succulents when ants start crowding your plant area.


Black aphids on a Coral aloe flower. Photo via Succulents and More

Treatment of Aphids

You can easily get rid of aphids by using a high-pressure garden hose a couple times. Be careful not to damage your plants while you do it. If the aphid problem continues, try spraying the plants with soapy water or a systemic insecticide. Repeated treatments may be necessary for several days to eliminate any survivors.


ROT


For succulents and cacti, cold or damp conditions caused by a fungal attack or overwatering may cause rotting of roots and stems. When there is a high level of moisture in the growing environment of the plants, rot is likely to occur because bacteria and fungi develop vigorously in this type of condition. The rotten tissues tend to turn red, brown, or black. The parts that have gone rotten are usually soggy, slimy, and emit a bad odor. Rot usually starts from the root up, thus when you notice any obvious changes on the plant, there is probably no way to save it.


A rotten Echeveria. Photo via Garden Answers

Control of Rot

  • Cut off all the rotten parts if the plant has just started to rot in a small specific region. Then let the uninfected part of the plant continue to grow.

  • If possible, cut the stem well above the rotten part and propagate it. Sometimes it might be possible to re-root and grow into a new healthy plant.
  • Avoid planting the body of your succulents so close to the soil to prevent the leaves from picking up some moisture from the soil, leading to rotting leaves.
  • Improve ventilation, do not overwater and avoid leaving your succulents in a cold damp condition. Make sure your soil is porous, well drained and doesn’t hold water for an extended amount of time.







Newsletter