Scale insects and mites are the most common insect pests of dracaena. Dry tips and edges are usually caused by too little humidity. Round dry patches and streaks on the leaves may be caused by excessive sunlight on the foliage. A sudden loss of many leaves can be caused by changes in temperature, drafts, too much water, poor drainage or heavy insect infestations. Leaf tips and margins may burn or become yellow if plants are fertilized too heavily.
Dracaena is very sensitive to fluoride.
Symptoms include yellowing of the tips or margins of the leaf or dead, scorched areas. Avoid potting soils that have a high percentage of perlite and keep the soil pH between 6.0 and 6.5 to prevent fluoride from causing injury. Do not use fertilizer which contains superphosphate since it often has high levels of fluorine. If a plant that has been growing in dim light is moved to a brighter spot, the new leaves will be thicker and stronger and growth rate will increase. Allow dracaenas to dry slightly between waterings .