[PDF]Index Of Plant Diseases In The United States

Plant Pests of Importance to
North American Agriculture

INDEX OF
PLANT DISEASES

IN THE

UNITED STATES


AGRICULTURE HANDBOOK
No. 165

Crops Research Division
Agricultural Research Service


UNITED STATES DEPARTMENT of AGRICULTURE


BELTSVILLE BRANCH

UNITED STATES
DEPARTMENT OF AGRICULTURE
LIBRARY


Plant Pests of Importance to
North American Agriculture


INDEX OF
PLANT DISEASES

IN THE

UNITED STATES


CROPS RESEARCH DIVISION
AGRICULTURAL RESEARCH SERVICE
UNITED STATES DEPARTMENT OF AGRICULTURE


AGRICULTURE HANDBOOK NO. 165


Issued August I960


shington, D.C.


or sale by the Superintendent of Documents, U.S. Government Printing Office
Washington 25, D.C. — Price $3.75


CONTENTS


Page

Scope 1

Nomenclature

Geographic distribution

Geographic regions ^

Plant diseases 4

Host index 486

Scientific names: families and genera 4§6

Common names 4<^

List of authors of plant-parasite names; recommended abbreviations


PREFACE


This Handbook is truly a cooperative accomplishment. Ever since the Plant
Disease Survey was founded, in 1917, each member of the staff has, at one time or
another, worked on the project. Paul R. Miller directed the work. Freeman Weiss
compiled the first part of the Handbook; Muriel J. O'Brien took over the task of
completing it. J. A. Stevenson was responsible for checking fungus nomenclature;
Nellie W. Nance, for abstracting and cataloging much of the basic data; and Jessie
I. Wood, for critical review. Host nomenclature was checked by S. F. Blake and his
associates in the New Crops Research Branch, and nematode names by workers in
the Crops Protection Research Branch, Nematology Section.

The principal sources of data were reports from plant pathologists throughout
the country to the Mycology and Plant Disease Reporting Section (formerly the
Plant Disease Survey), and the Section's index of the literature on plant-disease
occurrence. The National Fungus Collection of the Smithsonian Institution (formerly
the Mycological Collections of the Department of Agriculture) constituted another
source of information, as well as a means of verifying identification of disease-
producing organisms.

This Handbook supersedes Department Bulletin 1366, "A Check List of
Economic Plants of the United States," issued in 1926. It replaces the processed
report, "Index of Plant Diseases in the United States," issued in six parts, from 1950
to 1953.

The Handbook does not constitute a revision of the "Index," issued from 1950
to 1953. There are no real changes in content. Condensation of the introductory
explanation, and some minor changes, mainly in the host descriptions, to permit
better arrangement of the printed page, are the most conspicuous differences from
the original "Index." The only nomenclatorial changes are insertion of the current
names of the root-knot nematode and the curly-top virus in the first part and
correction of Xantbomonas solanacearum to Pseudomonas solanacearum in the latter
part of the Handbook. Authorities for species are more consistently cited, and a few
typographical errors are corrected. There are no additions to hosts, diseases, or
distribution.


Id


ii


Index of Plant Diseases in the United States


SCOPE


This Handbook lists more than 1,200 host
genera and some 50,000 parasitic and non-
parasitic diseases. The scope of this index has
been broadened with respect to the number and
variety of plants that are considered "eco-
nomic." In the earlier "Check List" of 1926
very few noncultivated plants, except forest
trees, and no weeds were admitted. Yet many
such plants possess economic importance for
some special reason. Even weeds may occupy
a significant place in a plant-disease index,
since they often harbor pathogens that also
infect crop plants.

As it is important to obtain disease-resistant
plants by selection or by breeding from resist-
ant relatives, the index indicates the species
and sometimes the varietal relationships be-
tween host and parasite.

The inclusiveness of the present list has been
extended not only with respect to the number
of host plants represented but also by less
selectivity among the associated organisms on
the basis of disease-producing capacity. The
simplest way to make an index satisfactory to
all prospective users is to include every avail-
able record, but difficulties mount as more and
more selection is practiced. For example,
among the wood-inhabiting fungi, it is easy to
list all species (assuming that they can be dis-
tinguished and are properly identified) that
have been reported upon a particular kind of
substrate. Similar nonselective lists, repeated
for each kind of host, would result in imprac-
ticable bulk in an index. On the other hand, the
Check List of 1926 attempted to include only
the wood-inhabiting fungi "known to cause
definite diseases or rots of living trees or tim-
ber, for which the symptoms have been de-
scribed in pathological literature." It omitted


"saprophytic species" and "those whose eco-
nomic importance has not been demonstrated."
In this Handbook a middle course has been
followed, in which all wood-inhabiting fungi
are included that are described in literature as
producing a rot, especially if occurring on
trunks and branches of sizable dimensions.
Thus, fungi contributing to the decay of
stumps, logs, and slash and those causing heart
or sapwood rots of standing trees and decay of
structural timbers are included.

A major problem in the selection of items
was posed by the numerous bark-inhabiting
Ascomycetes and Coelomycetes. Many of them
are, respectively, the perfect and imperfect
stages belonging to single life cycles, of which
either or both phases may have been identified.
Some are known, usually in the imperfect stage,
to cause twig blight, dieback, and canker ; often
the perfect stage is produced only after death
of the affected parts, but the organism as a
whole is parasitic. Many others grow only on
dead parts of living plants and are designated
as "perthophytes" ; though not parasitic, they
are sometimes pathogenic. Most lists of plant
diseases include both groups. A third and per-
haps larger group of leaf- stem-, and twig-
inhabiting fungi develop on dead plants, and
are called "necrophytes" ; they are usually ex-
cluded from lists of plant diseases and are
found only in inclusive lists of fungi. The
boundaries separating the three nutritional
groups are tenuous at best. Furthermore, rep-
resentatives of two and sometimes all three
groups may be found on the same leaf or stem.
As one of the purposes of such an index as this
is to facilitate the identification of pathological
specimens, it is preferable to include as many
organisms occurring in similar associations as


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9


AGRICULTURE HANDBOOK 165, U. S. DEPARTMENT OF AGRICULTURE


space limits permit, and to distinguish them by
annotations as to pathogenicity or other char-
acters. Thus, parasitic organisms are differen-
tiated by giving a general or specific name of
a disease that they may cause, and perthophytes
by noncommittal expressions such as "on
leaves" and "on stems. " Necrophytes can be
further distinguished by specifying dead leaves,
stems, or other parts, but present information
is not sufficient to make these distinctions in all
cases.

For example, on Mains sylvestris (apple),
we may have Num miliaria disc r eta, blister
canker; Valsa leucostoma, on twigs and
branches, canker; and Daldinia concentrica, on
dead wood.

In addition to the organisms that are para-
sitic or pathogenic on living plants, account
must be taken of those causing spoilage or


deterioration of agricultural produce and cer-
tain byproducts. The fungi that cause decay of
structural timber and the fungi and other
organisms that are responsible for spoilage of
fruits and vegetables in commerce are usually
accorded recognition in any list of plant dis-
eases. However, those causing wood stain
(without decay) of logs and various forms of
fiber deterioration usually are omitted. Al-
though phytopathology may justifiably restrict
its field to the ailments of growing plants and
their primary products, industrial mycology
must take account of the effects of fungi on
some manufactured products. Without attempt-
ing to extend this index into such areas as the
deterioration of textiles and other manufac-
tured plant products, the organisms associated
with fiber deterioration — for example, in cot-
ton and hemp — may properly be included.


NOMENCLATURE


In accordance with the policy of the U.S.
Department of Agriculture, the scientific names
of host plants and associated organisms in the
Handbook are in general those sanctioned
under the International Rules of Botanical
Nomenclature. In resolving questions of nomen-
clature pertaining to host species, Bailey's
"Hortus," "Standardized Plant Names," Ren-
der's "Manual of Cultivated Trees and Shrubs/'
and "Index Kewensis" have been the standard
guides. Controversial matters were referred to
the botanical specialists of the Department.
Common names, where given, are mainly from
"Hortus" and the "Standardized Plant Names"
or from regional floras.

A wholly consistent application of the Rules
of Nomenclature to fungi is not at present
feasible. For example, for the rust fungi the
nomenclature of Arthur's "Manual of the Rusts
in United States and Canada" has been fol-
lowed, though it deviates from the Rules in
matters affecting a few names. The nomencla-
ture of the downy mildews conforms to the rule
giving priority to the specific name first applied
to the perfect stage, although in a few in-
stances this results in the displacement of
familiar names, which are, however, also given.
How to apply the Rules of Nomenclature to
some of the powdery mildews, Microsphaera
aim for example, has not been satisfactorily
determined, but certain names, equivalent in
usage to nomina conservanda, have gained wide
acceptance. Several fungi that are commonly
found in nature only in the mycelial or sclero-
tial state, though possessing known Basidiomy-
cetous fructifications (e. g., Rhizoctonia solani,
R. crocorum, and Sclerotium rolfsii) , are ordi-
narily listed here under the cited names, since
the production of the perfect stage is rare or


unknown in nature and may require special
technique in culture. Sclerotium bataticola is
usually listed under Macrophomina phaseoli, its
pycnidial state, since this is readily produced
in culture.

The pleomorphic Ascomycetes are usually
listed under the perfect-stage name, but a cross
reference from the name of the often more
familiar conidial stage is given wherever this is
thought to be helpful.

In the nomenclature of certain Hymenomy-
cetous genera having a large number and vari-
ety of species, as Polyporus, Porta, and Fomes,
a conservative disposition has been followed for
the most part in retaining these generic names,
although several authorities have proposed
ways of subdividing them. There is no compre-
hensive and generally accepted treatment of all
species in our range, however. The genera
segregated from Hijdnum are accepted here
because authorities appear to be in closer agree-
ment on its subdivision than they are on
Polyporus.

The names employed for bacteria conform
generally to those in the sixth edition (1948)
of "Bergey's Manual of Determinative Bacteri-
ology," and are arranged in alphabetical order
among the scientific names of other organisms.
As there has been thus far no general agree-
ment upon a scientific nomenclature for viruses,
they are here designated by the name most
commonly applied to the associated disease,
followed by the name of virus, according to the
binomial system of nomenclature as given in
Supplement No. 2 of Bergey's Manual. For the
convenience of those favoring K. M. Smith's
numerical designation, the corresponding name
in this system is also given.

Diseases of unknown cause that have distinc-


INDEX OF PLANT DISEASES


o


tive names and those attributed to nutritional
deficiencies and other specific physiological fac-
tors are listed under the names by which they
are commonly reported. Physiological diseases
of wholly nonspecific character, such as those
caused by high or low temperature or drought,
are not listed unless they are especially fre-
quent in certain plants (as leaf scorch in
maples used as street trees) or produce distinc-
tive effects.


Virus and physiological diseases and those
of unknown cause are grouped at the end of
the list of scientific names of organisms.

Common or descriptive names of plant dis-
eases have not been standardized in the United
States as has been attempted in England by a
semiofficial committee, which has issued a "List
of Common British Plant Diseases." However,
certain names that have long been familiar and
distinctive are listed.


GEOGRAPHIC DISTRIBUTION


The designation of the geographic range of
the various diseases and pathogens, in so far
as the available reports afford information,
follows nearly the same plan as that adopted
in Department Bulletin 1366. Thus, the desig-
nation "general" means that the disease or
pathogen is coextensive with host; "wide-
spread" means that the disease or pathogen is
reported from many scattered points, too
numerous to list separately, but with some gaps
in continuity that preclude the designation
"general." These terms are sometimes modified
by the addition of words such as "frequent" or
"occasional," to denote intensity as well as
range of occurrence. All these terms must be
considered in relation to the range, in nature
or in cultivation, of the host plant, but where-
as Department Bulletin 1366 made no mention
of host distribution, this information is now
provided.

Since an undoubtedly influential factor in the
occurrence of certain types of disease is the
climatic adaptation, or lack of it, of the host,
it seems important to indicate where the host
grows naturally or is successfully cultivated.
For woody plants, the Plant Growth Regions
of the United States as designated by Mulford
in Van Dersal's "Native Woody Plants of the
United States" have been used (fig. 1). For
cultivated plants, where temperature is the


predominant factor affecting the geographic
range, the Hardiness Zones as mapped by the
Arnold Arboretum and adapted from Wyman's
"Shrubs and Vines for American Gardens"
have been used (fig. 2).

Certain regional designations employed most
frequently are explained in the following list.
The original source of some records reported
distribution by areas not conforming to this
list and without further information; in such
cases the distribution is given as in the original
source. When the reported range covers an
indefinite area comprising more States than it
is practicable to list separately but not coincid-
ing with any one or more of the regional desig-
nations, a general circumscribed area is given,
usually proceeding from northeast to southeast,
southwest, and northwest. Sometimes, how-
ever, the direction is from north to south on
the east, then north to south on the west; and
there are other variations. It should not be
inferred that reports of the disease have been
made from every State in the circumscribed
area, but available information indicates that
it is likely to be found anywhere within or
adjacent to such an area. When reported dis-
tribution is less extensive the States are listed
alphabetically, sometimes in more than one
sequence if records indicate definite gaps in
distribution between widely separated regions.


GEOGRAPHIC REGIONS


Eastern States or The East

Xew England States: Connecticut (Conn.),
Maine, Massachusetts (Mass.), New
Hampshire (N.H.), Rhode Island (R.I.),
and Vermont (Vt).

Xortheastern States : New England and Dela-
ware (Del.), New Jersey (N.J.), New
York (N.Y.), and Pennsylvania (Pa.).

Middle Atlantic States: Delaware, Maryland
(Md.), New Jersey, and Virginia (Va.).

Southeastern States: Florida (Fla.), Georgia
(Ga.), North Carolina (N.C.), and South
Carolina (S.C.).


1 These regions do not always conform to the regional designa-
tions given by the U.S. Census Bureau.


Central States

North Central States: Illinois (111.), Indiana
(Ind.), Iowa, Michigan (Mich.), Minne-
sota (Minn.), Missouri (Mo.), Ohio, and
Wisconsin (Wis.).

South Central States: Alabama (Ala.), Ar-
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