Alfalfa varieties differ in fall dormancy, defined as growth during the fall. Nondormant alfalfa varieties are usually planted in mild winter areas for their ability to grow in the fall. However, fall growth of nondormant alfalfa may be undesirable in areas subject to repeated frosts or freezes. Nondormant, very nondormant, and extremely nondormant alfalfa varieties (fall dormancy class 8, 9, and 10) are adapted to elevations below 4000 feet in Arizona. Other dormancy classes not included in this publication are moderately nondormant varieties (fall dormancy class 7) which may be grown from 3000 to 5000 feet, and semi-dormant and dormant varieties (fall dormancy 6 and below) which are adapted to colder winter areas above 4000 feet.

We injected AGRA PHOS (Potassium Phosphite) 0-2.4-2, Propiconizole – 0.05%, Zn, Mn and Fe 0.105, 0.112, and 0.10% respectively, Zn, Mn and Fe 0.210, 0.220, and 0.200% respectively and Propiconizole – 0.05% + Zn, Mn and Fe 0.105, 0.112, and 0.10% respectively using a low pressure injection system for the control of Antrodia sinuosa in lemon trees. No treatment led to a significant reduction in fungal growth.

Environmental conditions between awn emergence and the end of flowering is the overriding factor in disease development. 2 The University of Arizona Cooperative Extension Cultural practices may be partially effective in controlling Karnal bunt but cannot eliminate the disease completely. Karnal bunt is most likely to be found in areas where lodging or water ponding have occurred.

The most important disease of woody dicotyledonous plants in Arizona is Phymatotrichopsis root rot (Cotton or Texas root rot) caused by a unique and widely distributed soil-borne fungus, Phymatotrichopsis omnivora. The fungus is indigenous to the alkaline, low-organic matter soils of the southwestern United States and central and northern Mexico.

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.

Nematodes are microscopic round worms found in many habitats. They are the most abundant multicellular organisms on earth. Most are beneficial memebers of their ecosystems, but a few are economic parasites of plants and animals. There are several plant parasitic nematodes that cause problems on landscape and garden plants in Arizona and the most widespread and economically important are the root-knot nematodes. This article discusses the hosts and environmental conditions, symptoms and disease of root-knot nematode, and the prevention / control method to it.

Dwarf mistletoes are parasitic flowering plants that grow within host plants for about two years before producing characteristic yellow to orange or green to brown leafless aerial shoots on the outside of infected host tissue. They occur only on conifers in the pine family in Arizona and are usually host specific. This article gives information about the disease cycle, the symptoms and prevention and control methods for dwarf mistletoes.

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.