Black vine weevil

Black vine weevil larvae are C-shaped white grubs that devour roots underground, while adults are nocturnal beetles that chew leaf edges. Larvae destroy the root system, preventing the plant from taking up water and essential nutrients. Without treatment, root destruction causes sudden wilting and plant death, even when leaf damage remains limited.

Signs to check

• Clean, semicircular, scalloped notches in the outer edges of leaves.
• White, legless, C-shaped larvae, 8–10 mm (about 0.3–0.4 in) long, visible in the potting mix.
• Sudden wilting despite adequate watering, caused by root destruction.
• Slow-moving, nocturnal black beetles, 8–10 mm (about 0.3–0.4 in) long, hiding at the base of the plant during the day.

What you may see

• Scalloped notches in leaf edges · Leaf edges have neat, regular semicircular cutouts, as though punched out along the margin.

What to do now

Trap and identify plant pests

1. Buy yellow sticky traps, available at garden centers or online.
2. Remove the protective film and insert a trap into each infested pot, just above the potting mix where the insects emerge.
3. For larger plants, you can also hang traps from the lower branches.
4. Check the traps every 2 to 3 days to monitor how many insects they catch.
5. Leave the traps in place for at least one week to get a good picture of the pest population.
6. After a week, identify the insects caught. Fungus gnats look like tiny black flies, while whiteflies are small white flies.

Prevention

• Inspect every new plant carefully before bringing it into your home.
• Let the top 3–5 cm (about 1.2–2 in) of potting mix dry between waterings to discourage fungus gnat larvae.
• Avoid leaving standing water in saucers.
• Keep leaves clean and free of dust so early signs of infestation are easier to spot.