Biology Reference
In-Depth Information
Endophyllum sempervivi III on houseleek and
hen-and-chickens. Succulent leaves may be cov-
ered with reddish pustules. This is not common,
but may be serious. Clean out infected parts.
Endophyllum tuberculatum III on hollyhock
and checkermallow.
eastern United States in 1822, present from Can-
ada to Florida and from Alaska to southern
California.
Gymnosporangium
Pucciniaceae. All but one species heteroecious.
Picnia and aecia usually on trees and shrubs of the
apple family; telia confined to cedars and junipers
except for one species on cypress; uredia want-
ing. Teliospores thick-or thin-walled, various in
form but mostly flat, tongue-shaped, expanding
greatly when moistened, usually with two cells;
walls smooth, one to several pores in each cell;
pedicel colorless, usually with outer portion
swelling and becoming jellylike when moistened.
Aecia are highly differentiated and conspicuous,
with catenulate aeciospores, deeply colored with
verrucose walls (see
Fig. 2
).
The life cycle is similar in all juniper leaf rusts.
In early summer, small, slightly swollen spots
appear on leaves of the pomaceous host, then
small raised specks in this area on the upper
surface, openings of flask-shaped pycnia embed-
ded in leaf tissue. After exuding an orange liquid
containing pycniospores, the specks are black.
Later, aecia push out on the underside of the
same spots as dingy white columns, rostelia,
with the outer coating rupturing to release
a powdery mass of yellow to brown aeciospores.
The ruptured segments sometimes make the open
aecium look star-shaped, but in the common
cedar-apple rust aecia are cup-shaped. Aecia are
also formed on fruit and tender green stems.
Aeciospores released during summer are wind-
borne to junipers. Mycelium winters in the juni-
per needle or stem, and in spring galls are started
that take a year or more to produce teliospores in
cushions or horns.
Gymnosporangium bermudianum 0, I, III on
stems of eastern and southern red-cedar in the
Gulf states. No alternate host; aecia precede
telia on small galls.
Gymnosporangium bethelii III on Rocky
Mountain juniper; 0, I on fruits of hawthorn.
Gymnosporangium bethelii III on stems of
prostrate and Rocky Mountain junipers; 0, I on
Frommeella
Pucciniaceae. Teliospores two-to many-septate;
aecia and uredia erumpent.
Frommeella duchesneae II, III on mock-straw-
berry, false strawberry, or Aztec Indian berry.
Arthuriomyces (Gymnoconia)
Pucciniaceae. Uredia lacking; aecia present but
without peridium;
teliospores two-celled, one
pore in each cell.
Arthuriomyces peckianus (formerly
Gymnoconia peckiana
(
G. interstitialis
).
Orange
Rust
of blackberry. 0, I, III on blackberry, dew-
berry and black raspberry, first described from
eastern United States in 1822, present from Can-
ada to Florida and from Alaska to southern Cal-
ifornia. Very bright orange spores cover
underside of leaves in spring. The mycelium is
perennial in the bush, living throughout the year
between cells of the stem, crown, and roots, each
season invading new tissue as new growth begins.
Shoots may be bunched, often with a witches'
broom effect; plants are dwarfed. Spraying is
useless; infected plants never recover. Plant
only healthy stock, obtained from a nursery
where the disease is unknown. Remove infected
plants showing upright habit of growth, yellow
color, and glistening yellowish dots of pycnia
before the orange spore stage appears. Black-
berry varieties Eldorado, Orange Evergreen, Rus-
sell, Snyder, Ebony King, dewberry
Leucretia
,
and boysenberries are quite resistant.
Gymnoconia peckiana (G. interstitialis) (see
▶
Arthuriomyces peckianus
).
Orange Rust
of
blackberry. 0, I, III on blackberry, dewberry
and black raspberry, first described from
