Mammillaria lauii · Succulent
Mealybugs: Isolate the plant and treat with a systemic insecticide or dab spots with alcohol-soaked cotton wool.
Scale insects: Remove small infestations manually or apply a recommended horticultural oil or insecticide.
Root rot: Ensure well-draining compost and allow the soil to dry out completely between waterings.
Vine weevil: Use nematode treatments in the soil during warm months or apply a granular insecticide.
Overwatering: Reduce watering frequency and ensure the pot has adequate drainage holes.