• Cotton (Texas) Root Rot

      Olsen, Mary W.; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009-05)
      Cotton root rot commonly causes a sudden wilt and death of susceptible plants in summer months but may also cause a slow decline, especially at cooler temperatures. So, positive identification of disease by an experienced person is essential. This publication addresses the symptoms, environmental conditions, disease, prevention and control methods, sampling, identifying susceptible plants and the tolerant and immune plants of cotton root rot.
    • Damping Off

      Olsen, Mary W.; Young, Deborah; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011-01)
      Damping off is caused by several different fungi under different environmental conditions. The fungi include Pythium, Rhizoctonia solani, and Thielaviopsis basicola. This article discusses the symptoms, environmental conditions, diseases, prevention and control methods for the damping-off caused by fungi.
    • Diseases of Urban Plants in Arizona

      Olsen, Mary W.; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1999-04)
      Geographically, Arizona can be divided roughly into four areas, southwest, central, southeast, and northern. These regions correspond with four climatic zones, allowing a large and diverse number of plants to be grown for landscaping purposes. But, interestingly, in this desert environment many of the parasitic diseases in landscape plants are caused by a limited number of plant pathogens. This publication discusses some of those diseases that are sufficiently important to the urban plants in all areas Arizona.
    • Fire Blight

      Olsen, Mary W.; Young, Deborah; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011-01)
      Fireblight is a bacterial disease that affects only plants in the rose family, particularly apple, pear and pyracantha. This article briefly discusses the symptoms and environmental conditions for this disease and the way to control it.
    • Powdery Mildew

      Olsen, Mary W.; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011-01)
      Powdery mildew, a plant disease, appears as white, powdery spots on the leaf surface of several different kinds of plants. They are specific to their hosts and one type will infect only certain plants, usually those in the same or closely related plant families. This publication discusses the symptoms, environmental conditions, disease of powdery mildew and the methods used to prevent / control this plant disease.
    • Problems and Pests of Agave, Aloe, Cactus and Yucca

      Kelly, Jack; Olsen, Mary W.; Plant Sciences, School of (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011-03)
      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.
    • Sooty Canker

      Olsen, Mary W.; Young, Deborah; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011-01)
      Sooty canker causes cankers and dieback in tree branches. This article briefly explains the host, symptoms, environmental conditions, disease and preventing / controlling method for sooty canker.
    • Susceptibility of Mesquite Species to Powdery Mildew in Arizona

      Nischwitz, Claudia; Olsen, Mary W.; Department of Biology, Utah State University, Logan, Utah; University of Arizona, College of Agriculture and Life Sciences (College of Agriculture, University of Arizona (Tucson, AZ), 2014-12)
      Mesquite (Prosopis sp.) is a popular tree in landscapes in Arizona because of its drought tolerance and attractive growth habit. Powdery mildew has been observed from late summer until early spring on mesquite leaves. It has been identified as Pleochaeta polychaeta based on morphological descriptions and comparison to herbarium specimens. Surveys were conducted in fall 2008 through winter 2009 at two locations in southern Arizona to determine the susceptibility of different mesquite species to powdery mildew. Twelve mesquite trees representing two species were sampled at Texas Canyon near Willcox, AZ, and 177 trees representing eight species were sampled at the University of Arizona campus in Tucson, AZ. The North American mesquite species P. glandulosa var. glandulosa and P. velutina were infected with powdery mildew at the University of Arizona campus and P. velutina at the Texas Canyon site. No powdery mildew was observed on P. alba, P. cinerea, P. nigra, P. chilensis, P. pubescens and P. chilensis x flexuosa. The powdery mildew affects the aesthetic value of severely infected trees but seems to have little effect on long term tree health.
    • Verticillium Wilt

      Olsen, Mary W.; Young, Deborah; Plant Pathology (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011-01)
      Verticillium Wilt causes wilting and yellowing of leaves, death of limbs, often on one side or a portion of the plant. This article provides information on the disease caused by Verticillium Wilt including the host, symptoms, environmental conditions, disease and the preventing / controlling method.