Reading some of the things I write about, one would think that I hate the whole entire insect world. But I don’t. No really, I mean it. There are specific members of that club that I think are quite fascinating. Dragonflies are one of them. With a variety of colours and their helicopter-style look, including the fact that they eat much-hated mosquitoes, aphids and other pesky bugs, they rank high on my list of favourites. So dragonflies are a fine example of just one of the ‘good’ bugs that I like.

Along with the good guys, there are also the cute ones. For example, ladybugs are cute. Butterflies are cute. I even think bees are cute. When they accidentally find their way into my home, I go out of my way to try and place them safely back outdoors. Of course, with bees there is always the possibility of being stung, so I make sure that I don’t leave myself vulnerable. The bee is cute but the sting is not cute at all, so I have to protect myself while trying to save the bee that is frantically banging against my window trying to get out. This is an example of ‘cute’ bugs whose lives I will spare.

And just to show that I really do have respect and appreciation for winged, multi-legged and exoskeletal critters in this world, I’ll also applaud a few of the beneficials such as: Parasitic Wasps, Honey Bees, Rove Beetles, Soldier Beetles, Bald-Faced Hornets...and so on... Even though I don’t find them all visually appealing, it doesn’t matter; they are the ‘good’ bugs.

So there are many bugs, most of which you’ll usually encounter outdoors in the gardens, which I value because they are fascinating, cute or beneficial. Sometimes they are all three.

But not mealybugs.
Mealybugs are not cute. Or fascinating. Or beneficial.
These bugs are the most evil presence on plants.
They are the root of all evil.

If you grow houseplants, you probably say a little prayer at night before you go to bed to God, a higher power, a supernatural being, a picture of your cat hanging over your bed, maybe even your pet rock (remember those?); it doesn’t really matter who or what you pray to. The only thing that matters are the pleading words you use and the tone accompanying them.

My own humble appeal goes something like this: “O Green-Thumbed God of houseplant mercy. Bless all my indoor plant life that live in the face of insectism and grant them the courage to go about their daily growing. Protect all my plants from the wicked mealybugs; may these evil spirits never find their way into my home so that my plants will live in peace and remain mealy-free until the end of time. Grant hope to all plants around the world that one day all mealy hostilities will end. Amen.”

And if you’re lucky enough, with enough pleading, you’ll never encounter them on your indoor plants. If you’re not fortunate enough to avoid them completely, the next best thing is that it’s a small, inconsequential infestation. But is there ever an insignificant infestation when it comes to these thugs?

If you grow houseplants, mealybugs will find their way to them. Maybe not today or tomorrow but eventually. It might not be your house or mine but it will be someone’s house. One houseplant lover will not be so lucky and the mealybugs will show up at their door. And no amount of praying will stop them from causing considerable damage or spreading from plant to plant.

The most unfortunate thing that can happen is that you will make the mistake of assuming that the white, cottony blobs on your plant are some type of fungus. They are not. They are insects - mealybugs to be exact. They are one of the most common houseplant pests and one of the most frequently misdiagnosed as well. By misdiagnosing, you are also postponing treatment, which can prove extremely detrimental to your infected plant, decreasing its chances of survival as each bug-ridden day goes by. By delaying treatment you are also putting your entire collection of houseplants at risk.

Mealybugs spread from plant to plant easily. They are not gourmet or finicky feeders; they’ll eat any plant close at hand. And they won’t just fade away either. They will put up one heck of a fight once they move in with you, unwilling to give up their right to coexist in your home. They are, by far, the worst houseplant pest to go to war with. This is an insect that can certainly win both the battle and the war if left to breed numerous generations. Ask a seasoned houseplant lover about this pest and it’s likely they’ll tell you that they will happily swap a mealybug infestation for a scale infestation any time, swearing that the latter is easier to wipe out. And battling an invasion of scale is not exactly a day at the beach, so you can only imagine how much plant lovers hate dealing with this beast.

Now that I’ve scared everyone out of their wits about this insect of horror, let’s learn a little about them and then find out how to exterminate them. Yes, they can be conquered; they are far from being immortal. But you must catch an infestation in its early stages or it may not be worth a battle.


Meddling Mealies

The first thing that struck me as intriguing – or rather confusing – is the contradictory information that you run across on the internet when researching about this bug. Some websites will insist that mealybugs are fairly easy to control since they reproduce and move slowly. Others insist that this insect is difficult to eradicate because it reproduces very rapidly.

Well, which one is it? Probably both.

I personally think it all depends on a couple of factors. I trust that reproduction for any pest is indeed rapid when natural predators are not around and the conditions are ideal. A hot and dry combination will encourage breeding while the opposite will hinder it; it’s only logical. Your home environment is very unlikely to house natural mealybug predators but it sure as heck will give shelter to that warm and arid brew. An indoor environment is not only a safe haven for these nasty insects, away from predatory bugs, but also a cozy vacation spot where the temperature is perfect and the menu is just right.

Physically, these insects are small, white, soft-bodied and oval in shape; they resemble white woodlice. Up to about a ¼ inch long, they can wrap themselves in sticky, white ‘wool’ covering that they secrete. This ‘cottony’ or ‘waxy’ looking coat is there for a purpose – defense; it protects them against predators and is capable of repelling water and even insecticide. If you break the cocoon they build to protect themselves, beneath it you will find a yellowish-gray insect. Some of the places I researched also suggested that the actual mealybug body is a pink shade. My question is: does it really matter? You will most likely race to start some form of extermination treatment when you notice cotton-like deposits on your plant and finally realize that it’s the dreaded mealybugs and not a form of fungus. Do you honestly see yourself cracking the cotton shell during this frantic period to check out what colour this insect – the worst one to end up on your houseplants – really is? Nah.

It’s not the males that cause major damage; it’s the females that actually feed on plant sap by attaching themselves to a host plant. The males of these pests, on the other hand, are short-lived. They don’t feed on the plant as adults; they exist to fertilize the females. Females of some species don’t even need the males; they reproduce without mating (parthenogenesis). There are numerous generations of mealybugs per year, so it’s best to act quickly when signs of mealybug are found.

Mealybugs, closely related to scale, drain a plant of its juices much like aphids do with their sucking mouthparts. The damage caused by their feeding tactics weakens and stunts plants. It causes the yellowing of leaves, leaf distortion and premature dropping of foliage. Infected areas may also be coated with a sticky layer that the bugs produce called honeydew - it is similar to what the evil aphids manufacture – which in turn produces a black fungus commonly referred to as ‘sooty mold’.

Severe infestations resemble cotton patches and can be found anywhere on the plant. Typically, new growth is where these pests congregate and attack, therefore you can usually spot the beginnings of an infestation near budding tips. If you suspect that your plant has mealybugs from its shoddy appearance or the presence of honeydew or mold, you should also inspect the upper growth of your plants, underneath the foliage, along the stems or leaf veins and wherever leaves join.

If left unchecked, mealybugs can (and will) eventually kill a plant.


Arm Yourself And Wage War

If you discover mealybugs on any plant in your home – hopefully it’s only one victim – take action immediately. You don’t want to give them time to breed more evil offspring; the bigger the infestation, the uglier and tougher the battle. A huge invasion of mealybugs is the mother of all indoor insect wars. My personal advice is: unless there’s a significant reason for trying to save your plant, if you discover a severe infestation and the plant if easily replaceable, do not hesitate to toss it – soil, pot and flora. If you simply can’t part with any plant, go ahead and fight for it but don’t count on an easy victory. It’s going to get ugly and the war will last for a long time, sometimes months worth.

Extermination of these nasty bugs proves difficult because they are often found nestled in the nooks and crannies of your plant where it’s difficult to spray. Since your treatment will only work upon direct contact, if the mist doesn’t reach them in their cozy hiding place, they will materialize once again with a whole new generation right when you think the nightmare is finally over. You’ll wonder if they appear out of nowhere and it’ll seem as if they do. They don’t. They get transported indoors by people and pets, they get chauffeured from plant to plant by the same accommodating travelers and they will crawl from one plant to another to infect a whole collection of vegetation. If you don’t chase them out of your home, they will claim an entire area of living green as their own. They’ll eat and breed to their heart’s content.

Their protective coating also repels water so a simple mechanical approach is not entirely effective; rinsing the plant under running water does not automatically cleanse the evil away. Unlike spider mites, mealybugs are pretty darn good at holding on. It takes quite a strong spray and quite some time to dislodge them. I have held a leaf with mealybugs on it under a strong current of water and it took over 60 seconds and ample water pressure for just two or three of those horrible bugs to let go and drop. That’s a lot of muscle for a critter so small. Thankfully, I have only seen mealybugs up close once in the past twenty years of growing houseplants. The bigger blessing is that there were only a few of them present on the infected plant. But even with such a small invasion, the battle was a tough one.

Isolate an infested plant at once. If there is more than one plant, keep them away from one another as you treat them. You don’t want to cleanse one thoroughly from mealybugs only to have them move in again from the plant next door. It will end up becoming a mealybug revolving door with no end in sight. How far should you isolate? The next door neighbour’s house is a good place to start, another city is even better. All kidding aside, separate infested plants from uninfected ones as best as you can. It’s not unheard of to find mealybugs on a previously bug-free plant, which was in an entirely different room from the bug-ridden one, so just do what you can and don’t stress over it more than necessary. Mealybugs are easily transmitted on your hands, your clothing, dusters, etc.

Rubbing alcohol is one of the most effective treatments for these nasty bugs; it strips their protective waxy coating and dehydrates them, allowing you to easily wipe or rinse them away. If the infestation is minimal, dunk some cotton swabs in rubbing alcohol, dab the insects with it and wash them away with the saturated cotton or under running water. Be merciless. Together with alcohol wipes, use brute force when possible; crush, squish and pulverize them with your fingers, then rinse them away with water or wipe them off with cotton swabs dipped in alcohol.

Pick up a plastic misting bottle – preferably inexpensive – and prepare an effective mealy-extermination spray. Fill it with one part (70% isopropyl) rubbing alcohol to three parts water. Mist your infected plant thoroughly, top to bottom, making sure to douse the nooks and crannies of your plant where the mealybugs will take refuge and the alcohol solution is likely to miss them. Your spray has to make direct contact with the bugs for the extermination to be successful. Repeat this application for several weeks – twice a week is highly recommended – to be completely rid of the little demons. This method is more efficient and effective than simply wiping with cotton swabs since it’s more likely to make contact with the newly hatched mealybugs that go into hiding. Many houseplants growers that I’ve met over the years create their own solutions for insect battles. In addition to the alcohol, some plant owners add a few drops of mild dishwashing liquid to the mister.

Rubbing alcohol sprays have been around for years and houseplant growers either swear by them or warn that they cause leaf damage. In my own opinion, it does both – effectively eliminates pests and causes leaf damage. It all depends on your plant. Perhaps the best thing you can do is spray a small area on one leaf to test the effects and proceed accordingly. Just make sure to dilute; using full strength alcohol as a spray will probably prove detrimental to any plant.

Commercial insecticidal soap is another suitable method for the treatment of mealybugs. Because there are several types available, read the label before purchasing to make sure that mealybugs are included as part of the list of insects that the product will be effective against. In the past I have picked up insecticidal soaps that do not include mealybugs. Alcohol can also be combined with insecticidal soaps. Mix up an alcohol-insecticidal soap spray by substituting alcohol for half the water required for the dilution recommendations on your product’s label.

No matter what treatment you use, repeat the application every 5 – 7 days until there is absolutely no sign of mealybugs left. You must repeat treatment for several weeks to make sure mealybugs do not surface from eggs that will hatch further down the line. Don’t take it for granted that they are completely gone when after only one treatment there is no physical evidence of them. They will surprise you with reinforcements one day from beneath the leaves of the treated plant or another one – perhaps one of your favourites – if you are not on your guard. Heed this advice. I don’t want to say ‘I told you so’. Repeat, repeat and repeat treatments.

For my hydroculture fans, I recommend the dunk and sterilize method after you have mechanically removed as many mealybugs as possible – the brute method of squishing and squeezing the life out of unwanted guests with your fingers. As soon as you have claimed a few evil mealy lives with direct force, if your plant fits comfortably into your kitchen sink, mix up a large solution of ¼ alcohol to ¾ water in the basin. Add a couple of tablespoons of mild dishwashing liquid and drop your plant in there, twirling it around now and then for added success. Allow it to soak for about 15 minutes and then remove and rinse very well. As an added precaution, sterilize your pot and clay pellets in a mild bleach solution - 1/2 cup per gallon of water. Make sure to rinse pot and pellets as well and reassemble the hydroculture setup. Repeat as necessary for the next 3 – 4 weeks, once a week. Chances are one application will work since there are no places for mealybugs to hide when the plant is dunked. I have practiced this method and it is very effective.

When all is said and done and the mealybugs keep coming back, there is the amputation method. Prune and discard portions of your plant where the infestation is larger than life itself and threatening to spread like wildfire throughout your plant kingdom.

Finally, as I mentioned earlier, if there is an extremely severe infestation, consider the ‘grip-n-toss’ method. Grab the bug-ridden plant, place the whole kit and infested caboodle in a garbage bag and kick it to the curb. Extermination success: 100%


Photographs by: Whitney Cranshaw, Colorado State University
Photos are posted at: www.insectimages.org

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