Mealybug and thrips: a scouting routine that catches them in week one
Two pests account for nearly all succulent losses indoors, and both are far easier to eliminate in the first two weeks than the sixth. The difference is a five-minute inspection done on a schedule, at the right places.
Where mealybug actually lives
Not on the leaf faces. Root mealybug (Rhizoecus) lives in the top 2 cm of mix and on the roots, and foliar mealybug colonises the tightest available crevice: leaf axils, the base of offsets, the underside of the lowest leaf ring touching the soil, and the growing point of a closed rosette.
The visible evidence is white cotton, honeydew sheen, and ants. Ants are the most reliable early indicator — if you see ants on a succulent shelf, assume mealybug is present somewhere within 2 m and go looking rather than treating.
Thrips damage versus thrips presence
Western flower thrips on succulents produces silvery, stippled patches with tiny black frass specks, most often on the newest leaves deep in the rosette and on flower stems. The damage is usually noticed weeks after the insects arrived, which is why scouting has to be proactive.
To find the insects themselves, blow sharply into the centre of a rosette over a white sheet of paper. Thrips are 1–2 mm, elongated and translucent yellow to black, and they will move within a few seconds. Do this on three plants per shelf per week.
The five-minute weekly routine
Week's checklist: part the top three leaf axils of two plants with a toothpick; lift the pot of one plant and look at the drainage hole for root mealybug; blow-test one rosette centre; check the underside of the lowest leaf ring of one plant; look at the shelf surface for frass and honeydew.
Rotate which plants you inspect so that every plant gets a full check once a month, and always inspect any plant that has just arrived from a nursery or a swap, in isolation, for two weeks before it joins the shelf.
Treatment that does not require systemics
For light infestations, 70 % isopropyl alcohol applied with a cotton swab kills on contact and evaporates without leaving residue. Treat every seven days for four weeks to break the 21–28 day egg-to-adult cycle; a single application always fails because the eggs survive.
For root mealybug, unpot and wash the roots completely, cut away infested root sections, and repot into fresh mix in a pot that has been scrubbed. Discard the old mix rather than reusing it — the waxy egg masses survive drying for months. For thrips, a 1 % insecticidal soap spray applied at dusk, three times at five-day intervals, is usually sufficient indoors.
| Month | State | What the plant wants |
|---|---|---|
| January | Growth | Deepest rest. Water only if the lowest leaf ring softens; keep the room as bright as you can. |
| February | Growth | Late rest. Daylight is returning — begin adding an hour of supplementary light every two weeks. |
| March | Growth | Repotting window opens for summer growers. Trim roots, refresh the mineral fraction, dry for a week. |
| April | Growth | Growth restarts. First full watering at the rim, then resume the published interval. |
| May | Growth | Peak growth and the offset season. Feed at quarter strength every third watering. |
| June | Growth | Lengthening days, rising heat. Watch the leaf turgor test rather than the calendar. |
| July | Growth | Hottest weeks. Water in the evening, a third of the spring volume, and only on a visible symptom. |
| August | Growth | Heat eases at night. Prepare mix and pots for the autumn repotting window. |
| September | Growth | Autumn window for winter growers. Root-prune and repot while the soil is still warm. |
| October | Growth | Peak autumn growth. This is the season when most colour work should be done. |
| November | Growth | Daylight falls fast. Taper watering by a quarter and stop feeding entirely. |
| December | Growth | Slow, dry and bright. This is the colour peak for most genera in the collection. |
Tinted rows are the months this genus is genuinely out of action: no repotting, no feeding, and water only if the plant visibly shrinks.
Four things to take away
- Look in crevices, not on leaf faces: axils, offset bases, the lowest leaf ring, and roots.
- Ants on a succulent shelf mean mealybug within 2 m — go looking, do not treat blind.
- Blow into a rosette centre over white paper to find thrips; they move within seconds.
- Any treatment must repeat weekly for four weeks to break the egg cycle.
Informational only — This page is a cultivation record, not horticultural or plant-pathology advice. Any treatment should follow the product label and local regulation.