Gadenin日本語Get the appWork out which problem you have first
Lady palm damage tends to look similar from a distance: dull, marked, browning fronds. The treatments are completely different, though, and applying the wrong one wastes a season on a plant that grows too slowly to afford it. Take one frond to a window, turn it over and look at the underside and the stalk before you do anything.
| Symptom | Where to look | Likely cause |
|---|---|---|
| Fine pale speckling, dull gray cast, faint webbing | Underside of fingers, where they join the stalk | Spider mite |
| Sticky film on fronds or the floor below | Stalks and midribs | Scale or mealybug |
| Small brown limpet-like bumps that do not brush off | Stalks, cane bases, frond undersides | Scale insects |
| White fluff in the joints | Where stalks meet the cane | Mealybug |
| Neat brown tips on many fingers at once | Whole plant, evenly | Mineral or fertilizer salt burn |
| Fronds collapse, base feels soft, sour smell | Compost and cane bases | Root rot from standing water |
| Bleached or scorched patches on the sunward side | Fronds facing the window | Direct sun scorch |
Spider mite, the one that does real harm
Spider mite is the pest most likely to kill a lady palm, because it multiplies fastest in exactly the conditions of a heated room in winter: warm, still, dry air. The mites are almost too small to see, so you find them by the damage. Hold a frond up to the light and look for a fine pale stippling, as though someone had touched it repeatedly with a dry pin. Later the whole plant takes on a dull, dusty gray look and fine webbing appears where the fingers meet the stalk.
Act as soon as you see stippling. Take the plant to the shower or outdoors and wash both sides of every frond with a firm spray of tepid water, paying attention to the undersides and the crowded interior of the clump where mites shelter. Repeat every five to seven days for at least three rounds, because washing removes the adults but not all of the eggs. If washing alone is not winning, add an insecticidal soap or a horticultural oil, again applied to the undersides, and again repeated on the same interval. Raising humidity and lowering the temperature both work against the mites.
Isolate the plant while you treat it. Mites walk to neighboring plants and any nearby palm or ivy will be colonised within days.
Scale and mealybug
Scale insects are the other pest that settles on this palm for the long term. They look like small brown or tan bumps stuck to the stalks and the undersides of the fingers, and they do not brush off with a fingernail the way debris does. Under each shield an insect is drinking sap and excreting sugar, which is why the first thing many people notice is a sticky film on the leaves or on the floor. Mealybugs are the same problem in a white, cottony form, and hide in the tight joints where the stalks meet the canes.
- Isolate and inspect the whole plant Move it away from other plants and check every stalk and cane, including the parts hidden inside the clump. Scale is nearly always more widespread than the first few you find.
- Wipe off what you can reach Use a cloth or a cotton bud dipped in dilute soapy water, or in rubbing alcohol for mealybug, and rub each bump off individually. On a plant with few canes this alone can finish the job.
- Follow with horticultural oil Spray both sides of the fronds and the whole length of the stalks and canes so the film covers any insects you missed. Do this out of direct sun and never on a plant with bone dry compost.
- Repeat every ten to fourteen days, three times The mobile young hatch over several weeks and are the only stage the treatment kills easily. A single application always fails.
- Cut out fronds that are beyond saving A frond that is more than half brown or crusted with scale is not worth treating. Remove it at the base of the stalk, but never take more than a quarter of the healthy fronds at once.
Brown tips and root rot: the two problems that are not pests
Brown tips are the signature complaint of this palm and they are usually chemical, not biological. Lady palm is unusually sensitive to fluoride, chlorine, boron and to accumulated fertilizer salts, all of which are carried to the far ends of the leaf fingers and left there as the water evaporates. If the browning is a thin, even edge appearing across the whole plant rather than in patches, change your water source, feed at half strength or not at all, and flush the pot right through twice a year.
Root rot works the other way round: it starts unseen and only announces itself when several fronds go limp at once. It is nearly always caused by a decorative pot cover or saucer that is never emptied. If you suspect it, tip the plant out. Healthy roots are pale, firm and thick; rotted ones are black, soft and slide out of their skins. Cut all the dead ones away, repot into a fresh gritty mix in a pot no bigger than the remaining roots need, and keep it barely damp and shaded until new fronds appear.
Prevention and what to log
Almost all of this is preventable with two habits. Wash the foliage down thoroughly every couple of months, which removes mite colonies before they establish and takes the salt film off the leaves. And empty every saucer and cachepot twenty minutes after watering, without exception.
Keep a short record of each outbreak: the date you first saw it, which pest it was, what you used and how many rounds it took to clear. Spider mite in particular tends to return in the same weeks each year, when the heating goes on and the air dries out, and a record from last year tells you when to start washing the plant preventively rather than reactively.