Biology Reference
In-Depth Information
Lophodermium nitens Frequent but apparently
saprophytic on five-needle pines. Hysterothecia
short, black, shining.
Lophodermium piceae
Needle Cast
,
Needle
Blight
of fir,
Tar Spot
on fir and spruce, most
severe on young specimens. Needles turn yellow,
reddish, or brown, and drop. Short, shining black
hysterothecia are formed on all needle surfaces.
Lophodermium pinastri
Pine Needle Cast
,
widespread. Pycnidia appear in spring or early
summer as tiny black spots on browned needles,
followed by dull, occasionally shining, black,
short, elliptical hysterothecia. The fungus is
a weak parasite but can be epidemic in nurseries.
Bordeaux mixture will control it.
Lophodermium seditiosum
Needle Cast
of
scotch pine.
Phoma
Blackleg
.
Phoma eupyrena
Needle Cast and Blight
of red
fir and Douglas-fir.
▶
Rhabdocline
Ascomycetes
Apothecia innate, brown, exposed by irregular
rupture of epidermis; paraphyses present; spores
one-celled, becoming septate after discharge
from ascus, rounded at ends and constricted in
the middle.
Rhabdocline pseudotsugae
Needle Cast
of
Douglas-Fir,
Needle Blight
, common on Pacific
Coast and in Rocky Mountain States on native
Douglas-fir and in northeastern states on orna-
mental forms. The disease has reached Europe
on trees from western North America and is caus-
ing much concern there.
Needles are infected in spring or early
summer, with first symptoms showing as slightly
yellow spots, usually at ends of needles, in
autumn or winter. By the next spring the color
is reddish brown, and leaves have a mottled
appearance. In severe infection needles turn
a more uniform brown, and the entire tree
appears scorched. Apothecia are usually on
underside of needles, sometimes on upper. They
are at first round cushions; then the epidermis
ruptures to expose a brown, elongated disc.
Infected needles drop after ascospore discharge,
thereby living only 1 year instead of the normal
8 or so.
Control
Spraying with bordeaux mixture when
new needles develop, repeating twice at 10-to
14-day intervals has been suggested; also,
spraying with lime sulfur at time of ascospore
discharge in early summer. In forests, control
will probably depend on early elimination of
susceptible trees. Rhabdocline weirii.
Needle
Cast
of Douglas-fir.
Mycosphaerella
Blights
.
Mycosphaerella laricina
Needle Cast
of Euro-
pean larch and western larch.
▶
Cyclaneusma (Naemacyclus)
Ascomycetes, Rhytismatales
Apothecia bright-colored, soft, opening with
a cleft; paraphyses much branched;
spores
worm-shaped.
Cyclaneusma niveum (formerly
Naemacyclus
niveus
).
Needle Cast
, occasional on various
pines. Fruiting bodies tiny, elliptical, first waxy,
dark brown, later concolorous with leaf surface.
Naemacyclus
Cyclaneusma
niveum
).
Needle Cast
, occasional on various pines.
niveus
(see
▶
Pestalotia
Blights
.
Pestalotia microspora
Needle Spot
,
Cast
of
Torreya.
▶
