Plant Pathology and Plant Pathogens. John A. Lucas

Plant Pathology and Plant Pathogens - John A. Lucas


Скачать книгу
wilt of tomatoes, bacterial wilt of cucurbits Hypertrophy Growth regulation Club root of brassicas, maize smut, peach leaf curl Hyperplasia Growth regulation Crown gall, cocoa witches broom, peach leaf curl Leaf abscission Growth regulation Leaf blight of rubber, coffee rust, black spot of roses Etiolation Growth regulation Bakanae disease of rice Inhibition of flowering and fruiting Reproduction Choke of grasses Ergot of grasses, cereal smut diseases Abnormal coloration Pigment synthesis Grapevine leaf roll virus, citrus greening, tulip breaking virus Image described by caption. Image described by caption and surrounding text.

      Source: Courtesy of D.J. Royle.

      (b) Scanning electron micrograph of rust pustule on willow leaf showing spiny urediospores of the fungus.

      Source: Spiers and Hopcroft (1996).

      While visual symptoms are still routinely used to diagnose diseases and disorders in crops growing in the field, in recent years a range of molecular assay techniques have become available to directly detect the agents causing the symptoms. Such molecular diagnostics are discussed in more detail in Chapter 4.

      A useful distinction can be drawn between animate (biotic) and inanimate (abiotic) causes of disease (Figure 1.5). Many of the animate agents, including the microbial pathogens, the parasitic angiosperms, and some of the animal pests, are infectious. Due to their capacity for growth, reproduction, and dispersal, these agents spread from one host plant to another. Under particularly favorable conditions, they may be dispersed rapidly over wide areas and even entire continents.

      Pests

Diagram illustrating agents responsible for plant disease, disorders, and damage with 2 overlapping circles for biotic (left) and abiotic (right) having segments for animals, pollutants, physical factors, plants, etc.