Quotes from Royal Horticultural Society

Select a large bulb with several well-developed offsets. Clean off the soil from the offsets and pull them away from the parent bulb, taking care to preserve any roots. Prepare pots with a moist, sandy compost. Inset a single offset into each pot, and cover it with compast. Label, and water.

Symptons of tulip virus: Patterns of yellow discoloration (mosaics, ringspots, mottles) are common. Cause: Sub-microscopic virus particles in the sap of infected plants may be transmitted to healthy tissues by sap-feeding pests such as aphids, by nematodes or other soil-borne pests