12 pp. / plant disease bulletins; July 2006 original publishing date, rev. 10/08 / Cacti, agaves and yuccas are classified as succulents, plants that have highly specialized anatomical features such as thick waxy cuticles, fleshy or minimal leaves, modified leaves (spines), and roots with extra storage capabilities for food and water. These modifications allow them to survive and thrive in harsh desert environments. They survive long periods of drought in areas of sparse rainfall and intense heat. During stressful periods, many succulents cease to grow, drop unnecessary leaves, dehydrate and become dormant until conditions for growth return. Despite their adaptations, succulents suffer from diseases, insect pests and cultural problems. Some of the more common problems that occur in cacti, agave and yuccas in Arizona are discussed in this bulletin.