Mammillaria baumii · Succulent
Root rot: Ensure well-draining compost and allow the soil to dry out completely between waterings.
Mealybugs: Isolate the plant and treat with a systemic insecticide or wipe off with alcohol-dampened cotton buds.
Scale insects: Remove manually with a soft brush or apply a suitable horticultural oil spray.
Sunburn: Gradually acclimatise the plant to brighter conditions and avoid direct midday sun in summer.
Vine weevil: Use nematode treatments in the soil during warm months or apply a systemic insecticide.