Hi, my Dracaena warneckii used to consist of three canes, planted altogether in a pot. One and a half years ago, the tallest one started getting hectic, the leaves went brown on the edges (but not dry), then something happened like the cane was soaked from inside and the entire cane became black dry and died, although there were still some green leaves for quite some time. After some time when I was sure that the cane was dead, I didn't have the time to do anything, I just removed the dead cane. Somewhat six months later, the same symptoms occurred on the next tallest cane. Then, I was more careful, so I noticed some white flakes between the cane and the beginning of each leave. The second cane died in a similar way, before I managed to do anything. Then I decided to remove the next cane and replace the soil in the pot. Indeed, this gave the third (shortest) cane a summer of life. But just recently it also started having the white fuzzy flakes and seeming hectic. I removed them carefully and washed out the leaves. The suspects have this white fuzzy material of 3mm and in it there is an undefined black mass of 1mm, like a wet node of a cloth. Nothing like insects, just a black mass. There are also long things, i.e. 1-2cm, that look like a piece of hair. I read in some forums that these must be parasites that like dracaenas, but I didn't find a solution. Could somebody please identify the problem and suggest sth?
No idea what you mean by "hectic" (dictionary.com defines this as "characterized by intense agitation, excitement, confused and rapid movement"), but it sounds to me like you have two separate problems. White, fuzzy, cottony spots near the stem are probably mealybugs, an insect pest that sucks sap from the plant. Canes hollowing out from the inside and turning black are most likely the result of a fungus, Fusarium, or a bacterium, Erwinia, and you can tell the difference because Erwinia infection on a Dracaena smells horrendous. Both Fusarium and Erwinia could be the result of overwatering, an excessively water-retentive soil, cuts/wounds on the stem or roots, or some combination of the three. I've had people tell me that they observed their plants taking up less water when infested with mealybugs, and have observed this myself a few times, so it's possible that the mealybugs worsened an existing rot problem. Brown edges on Dracaena leaves also indicate overwatering (or sometimes mineral build-up in the soil). My Dracaenas do best when I water them thoroughly, then let the soil dry out almost entirely before giving them another thorough watering. It might be helpful to know what kind of soil you used to repot. I am unable to guess the identities of your black mass or piece of hair; neither sounds like any pests or diseases I'm familiar with. Mealybugs secrete a sugary substance called "honeydew," and sometimes mold will grow on honeydew where it's fallen on a plant, but that usually looks more sooty/powdery, not like a mass. My advice on this one would be to throw the plant away and start over with a new one. Plants are fairly cheap, and getting rid of a mealybug infestation can take a lot of time and energy. (I once spent a year and a half battling mealybugs on a cactus.) If the plant has extreme sentimental value or something, the simplest (but most time-consuming) way to deal with mealybugs is to wipe the leaves and stem off with rubbing alcohol on a paper towel, including the little crevices between leaf and stem (those are best attacked with cotton swabs). You'll have to repeat the treatment every 4-7 days, and continue doing so for a little while after there are no more bugs visible, because if you miss any, the problem will come back again later. Spray insecticides are unlikely to be particularly helpful, because the white waxy coating of the mealybugs repels water and keeps pesticides from reaching the insect. Spraying the plant with rubbing alcohol, followed by a spray insecticide, is somewhat more effective, but you still have to keep it up for a long time, it's very important to follow the directions on the label, and it's not necessarily going to be any faster than the rubbing alcohol and cotton swabs approach. There's not really anything you can do about Fusarium or Erwinia once they're already in the stem; if the infection hasn't spread very far up the stem, and the plant is still fairly healthy, one can sometimes cut off the healthy top and root it to start a new plant, but I wouldn't attempt this with a plant that's battling mealybugs.
Thanks for this very detailed opinion. Indeed, hectic was a wrong word. I haven't kept the description of the soil I used, it was regular soil bought from a neighborhood shop. I have also used it for planting flowers and probably other plants and I haven't noticed anything weird with them. The plant was indeed overwatered the first year, until it started the first symptoms. Since then I have radically reduced watering. Instead, I used a water spray to wet the leaves, because somebody suggested that they may need some humidity. Weirdly enough, the escalation of the problem occured after a 3 weeks of no watering at all. Ii don't get any smell, so the other thing must be the Fungus. I will follow your advice about cleaning the leaves of the plant with alcohol for a while, and see if it gets any better. I am very pessimistic because in previous cases the deterioration was very fast, but anyway, worst case I will throw it away and replace it. Thanks again
