Plant Diseases and Their Pathogens - Westcott's Plant Disease - page 51

Part III

Plant Diseases and Their Pathogens

Because this is a reference topic and not one to be read for pleasure or
continuity, most of you will come to the material you need in this section
by way of the index or the lists of diseases given under the different hosts in
▶

Part IV you will find a list of headings
under which diseases are grouped and described, from Anthracnose to
Witchweed. In the Host section,

Part IV . At the beginning of ▶

Part IV , the key word, for example, rot
or blight, is given in capital and small capitals, followed by the name of
the pathogen (agent causing disease) in boldface. In this Diseases section,
Chap. 3, the pathogens are listed in boldface in alphabetical order under
each heading such as ROTS or BLIGHTS and so on, followed by the common
name of the disease. This system was adopted for quick and easy reference
because trying to alphabetize hundreds of similar common names would lead
to endless confusion. Also, it allows a very brief summary of the classification
and diagnostic characters of each genus before going on to a consideration
of diseases caused by the various species. This brief summary is in small
type, so that it can be readily skipped by readers uninterested in the technical
details. Perhaps I am the only one who feels the need for this quick review, to be
used in conjunction with the classification given in

▶

Part II ; perhaps others
who have to answer questions over a broad field instead of their own specialty
can make use of

▶

these capsules sandwiched in between nontechnical

descriptions.
An alphabetical arrangement has the great disadvantage of being thrown
out of alignment every time the name of a fungus is changed, as it so
frequently is. In some such cases the old name is retained to avoid change
in order, but the present accepted name is also given. Sometimes names have
been changed under several hosts and the old name inadvertently retained
under others. And sometimes the old name is purposely retained because it is
so familiar to everyone. This is particularly true of a few fungi far better
known by their anamorph states than by the correct name of the teleomorph
state. A fungus not only can have several names; it also can cause more than
one type of disease. For instance, Pellicularia filamentosa is the present name
of the fungus formerly known as Corticium vagum when causing Rhizoctonia
rot of potatoes and Corticium microsclerotia when causing web blight of
beans. As Rhizoctonia solani , the name given to the sclerotial stage, the same