If you look closely at one of your prized houseplants and suddenly discover a bunch of fuzzy dots, it can be easy to freak out. We all hate seeing bugs, and these ones are among the most annoying of all: mealybugs. Mealybugs on plants are common, but often difficult to deal with.
What should you do? Let’s do into what they are, how to deal with mealybugs on plants and prevention.
What are mealybugs?
Mealybugs are small, soft-bodied insects that are considered to be pests by many people. That’s because these critters can be found on both indoor and outdoor plants, feeding off the plant sap.
Although small amounts of mealybugs may not cause much harm, if left unchecked, affected plants can start dying off.
As if that’s not bad enough, the presence of mealybugs on plants may also attract other unwanted guests, such as ants, who like to feed off the sweet honeydew that mealybugs excrete! In fact, ants are known to protect mealybugs in order to farm such a delicacy. Just what you needed: plant-sucking bugs and a biting army to back them up.
Excess honeydew also creates additional places for fungus and sooty mold to form, which can further damage plants.
Where do mealybugs come from?
Mealybugs are naturally found all over the world but thrive in warm, moist climates.
In terms of how they may enter your home, it’s sadly often through bringing home a new plant from an affected greenhouse or nursery, unless you yourself live in a warm, moist region where mealybugs naturally live. These pests can be found in everything from fruit trees to succulents.
But how do mealybugs spread? Well, once you have mealybugs on a plant at home, they can easily spread through contact with other plants.
This is especially true if you have a lot of houseplants bunched together with some overlap. For example, a cluster of plants kept together in a humid room, which is usually very good for the plants, is prime real estate for these freeloaders.
Did you know? Mealybugs can also spread plant diseases. Not something the casual houseplant enthusiast should be too worried about, but potentially disastrous for commercial plant growers like vineyard owners.Daane et al., 2012
Mealybug life cycle
The mealybug life cycle starts with an adult female laying anywhere from 300 to 600 eggs. Yikes! No wonder they can spread seemingly overnight. Eggs are usually deposited on the underside of leaves.
After laying eggs for about 2 weeks, the female then dies, her duties having been fulfilled. In about 1 to 3 weeks, the eggs hatch and the brown-yellow nymphs, also known as crawlers, begin crawling all over the host plant.
Did you know? The long-tailed mealybug, Pseudococcus longispinus, gives birth to live crawlers. Yuck.Daane et al., 2008
Once the nymphs find a place to settle and begin to feed, they start to develop a waxy coat, which gives them their characteristic look. The males eventually develop wings through metamorphosis while the females continue to molt, growing larger each time.
The females outlive the males, since the males’ sole purpose is to fertilize the females. The mealybug life cycle is so short that a whole generation of mealybugs can live and die in as little as a month. This is why getting rid of them can be difficult, especially as generations overlap.
Since things can quickly get out of hand, what can you do?
Did you know? Female mealybugs are the ones with the characteristic white, cottony appearance.
Mealybugs on plants: What should you do?
If you find yourself dealing with a mealybug infestation, here’s a list of things you can do to try and get the situation under control.
- If you have other houseplants, you should move the affected plant away to help prevent the spread.
- Prune any stems or leaves that are visibly affected to help stop the spread to other parts of the plant.
- Blast the plant with water to wash away any visible mealybugs.
- Dip cotton swabs in alcohol and dab any visible mealybugs to kill them.
- Use neem oil on the leaves. This oil is used to slow down or stop mealybugs from reproducing. It also acts as a repellent.
- Use Cryptolaemus montrouzieri, also known as mealybug destroyers. These natural predators of mealybugs feed on both mealybug eggs and adults. However, if there are ants protecting the mealybugs, you’ll need to get rid of the ants first.
- Use a pesticide, although this should be done as a last resort since using any kind of chemical can be harmful to other living things.
If you’ve tried everything and it seems like you’re just not winning, the safest thing you can do is cut your losses and dispose of any affected plants. This may be best if you have plenty of other houseplants that mealybugs may gravitate towards.
Although it can be a bummer to lose a favorite plant, you have to think about the ecosystem as well, whether it’s just within your house or outside. And the last thing you want is for the infestation to spread!
Tip: Here at Houseplant Central headquarters, infested plants are banished outdoors. In the warmer months the plant may pull through, while bugs might not like the switch from our cozy homes to the harsher outside world.
Mealybugs on plants: Prevention
Whenever it comes to infestations, it’s always best to be proactive instead of reactive!
Here are a few things you can do to make your plants less appealing to insect pests.
- Inspect any plants before purchasing them. While this is easy enough to do if you’re seeing the plants in person, it may be trickier if you’re ordering online.
- Quarantine new plants. If you’re bringing home plants, even from trusted sources, it’s best to keep them away from other houseplants for a couple of weeks. This will give you a chance to catch any pests before they wreak havoc.
- Inspect your existing plants whenever you water, carefully checking them over for any signs of infestations. Make sure to check under the leaves as well.
- Wipe down the leaves regularly. This can easily be done during inspection or watering. Not only does wiping down the leaves help deter pests, but the practice helps remove dust and dirt for better photosynthesis as well.
- Apply neem oil. Some people use the oil as a general preventative.
- Avoid overwatering. If the soil is too moist, it creates the right kind of environment that mealybugs, as well as other pests, love. Overwatering can lead to other problems as well, such as root rot.
Are mealybugs on plants harmful to humans?
Thankfully, it’s believed that mealybugs don’t bite or spread disease to humans, although some people may experience skin irritation if they come into contact.
The only real harm from these pests for everyday people is the stress and destruction they cause if you’re passionate about your plants!
Are mealybugs harmful to pets?
Fortunately, your pets are just as safe as you are. However, you should still always keep your plants, whether infested with mealybugs or not, out of reach.
It’s also important to keep in mind that while mealybugs themselves may not be harmful to your pets, certain pesticides used to control them may be.
Cover photo: Feey
Daane, K., Cooper, M., Triapitsyn, S., Walton, V., Yokota, G., Haviland, D., … & Wunderlich, L. (2008). Vineyard managers and researchers seek sustainable solutions for mealybugs, a changing pest complex. California Agriculture, 62(4), 167-176.
Daane, K. M., Almeida, R. P., Bell, V. A., Walker, J. T., Botton, M., Fallahzadeh, M., … & Zaviezo, T. (2012). Biology and management of mealybugs in vineyards. In Arthropod Management in Vineyards: (pp. 271-307). Springer, Dordrecht.