Question: My violet hasn’t looked very happy lately. The leaves look dull and a bit limp. There is a white substance around the base of the stem, which makes me suspicious. Could this be a pest problem that’s causing my plant to look this way, and how do I get rid of it?
Answer: It sounds like your violet may have mealybug. If you see slow-moving, white, waxy, insects hiding within the leaf axils of your plant, you may have foliar mealybug. Sometimes, they’ll look like litte bits of perlite–if it “squishes” it’s mealybug; if it’s crunchy, it’s perlite. That white substance around the base of your plant may very well be a mass of mealybug eggs. Soil mealybugs are harder to see, since they are smaller and they do most of their damage within the soil, to the plant’s roots. They, too, can leave egg masses on the soil surface, at the plant base. You’ll know for sure by taking the plant out of the pot and examining the root ball. You’ll see white patches, like “confectioner’s sugar” on the root ball or inside of the pot. These will be the egg masses of soil mealybug.
In either case, you’ve got a problem to deal with. Mealybugs can be difficult to get rid of without taking extreme, or costly, measures. If it’s not a valuable plant, and you don’t want to risk the problem spreading to the rest of your collection, it may be best to simply discard the plant. Too often, growers will take half-measures in an effort to save one plant, meanwhite letting it spread to the remainder of their collection. After (sometimes years) of battling, the original plant, as well as many others, end up being discarded anyway.
Should you want to keep the plant and fight the problem, be prepared to spend some time, effort, and money. To begin, you will need to use chemicals to eliminate the problem with certainty. Unfortunately, many of the chemicals that are proven to work can be either too toxic to wisely use in the home, too costly, or both. Chemicals such as Cygon, diazanon, or Malathion, once popular, and perhaps effective, are just too toxic to safely use in the home (though many of us did). Today, the insecticides of choice areMarathon and its liquid form, Admire. Both contain the active ingredient imidocloprid (look for this on the label if using another product). Though still toxic, and to be used with caution, it is much safer for home use than what’s been used in the past (it’s the same ingredient in the liquid flea medication you may be applying to your pet). Unfortunately, both are quite expensive for the small grower–$100 or more per container, making it impracticale for many small growers and hobbyists. Don’t waste your time and money on less expensive, less toxic, products like insecticidal soaps intended for in-home use. They are ineffective (regardless of what the label says) for problems such as mealybug.
Marathon come in a granular form (it looks like sand) and can be added to your soil mix when repotting the plant. For best results, prepare your plant by removing as much unnecessary foliage and roots as possible. Even better, remove all of the root ball and soil, leaving only the crown of the plant. Then wash the plant, using a mild dish detergent and room-temperature water. Fill a pot with soil and sprinkle the granular Marathon over the surface. As a precaution, wear protective gloves (and mask) while doing this. Next, moisten the soil, press the crown into it, and firm soil around it. Place in a clear container (like a large baggie), seal, then wait 4-6 weeks until rooted. Until you’re certain the plant shows no signs of mealies, keep it separated from your other plants. You might also want to start again from a leaf cutting, taking the same precautions.
Should you want to avoid using chemicals entirely, wash the crown in mild soap and room-temperature water, and reroot as described above. Though not foolproof, if you’ve done a thorough job of washing, you may be lucky enough to have eliminated your this way.