Biology Reference
In-Depth Information
a web from leaf to leaf, over petioles, flowers, and
fruit, in wet weather and at temperatures 70
to
90
F; in dry weather growth is inconspicuous
except on fallen leaves. The fungus is spread by
wind, rain, irrigation water, cultivating tools, and
bean pickers; it survives in sclerotial form from
season to season.
Control
Destroy infected plants; clean up refuse.
In Florida, do not plant beans between June and
September if web blight has been present. Use
a copper spray or dust.
Thanatephonus cucumeris (formerly
Pellicularia filamentosa
f. sp.
sasakii
).
Leaf
Blight
of grasses, clover, etc.
Thanatephorus cucumeris (formerly
Pellicularia filamentosa
f. sp.
timsii
).
Leaf Blight
of fig.
temperature than the fungus; shading transplants
is helpful.
Pestalotia sp. and Penicillium sp.
Flower Blight
on camellia.
Pestalotiopsis funerea (formerly
Pestalotia
funerea
).
Tip Blight
of conifers,
Needle Blight
,
Twig Blight
of chamaecyparis, retinospora,
cypress, bald cypress, arborvitae, juniper, yew,
and giant sequoia. The fungus is saprophytic on
dead and dying tissue and also weakly parasitic,
infecting living tissue through wounds under
moist conditions. It appears in sooty pustules on
leaves, bark, and cones.
Phacidium
Ascomycetes, Helotiales
Apothecia innate, concrete above with the epi-
dermis and slitting with it into lobes; spores one-
celled, hyaline.
Phacidium abietinellum (see
Penicillium
Penicillium oxalicum
Leaf Blight
of grass.
Nothophacidium
abietinellum
).
Needle Blight
of balsam fir.
Phacidium balsameae (see
▶
Sarcotrochilia
balsameae
).
Needle Blight
of balsam fir in New
England, of white and alpine fir in the Northwest.
Phacidium infestans
Snow Blight
of conifer
seedlings on fir and young pines in the Northeast,
also on arborvitae and spruce; on white and
alpine fir in the Northwest. This native fungus is
most damaging in nurseries, attacking foliage
under the snow. The needles turn brown, with
a covering of white mycelium, just as the snow
melts. In late summer and fall brown to nearly
black apothecia appear on underside of browned
needles. Ascospores are spread by wind, primary
infection being in autumn. Additional infection
occurs in late winter, when mycelium grows out
under the snow from diseased to dormant, healthy
needles.
Control
Spray nursery beds with dormant-
strength lime sulfur in late fall; remove infected
seedlings; dip new stock in lime sulfur before
planting.
Nothophacidium abietinellum (formerly
Phacidium abietinellum
).
Needle Blight
of
balsam fir.
▶
Pestalotia
Deuteromycetes, Coelomycetes
Acervuli dark, discoid or cushion-shaped, subcu-
taneous; conidiophores short, simple; conidia
fusiform, several-celled with median cells col-
ored, end cells hyaline, a short stalk at the basal
cells and a crest of two or more hyaline append-
ages, setae, from the apical cell (
Fig. 1
). Weak
parasites or saprophytes; some are treated under
Leaf Spots.
Pestalotia
Pestalotiopsis
funerea
).
Tip Blight
of conifers,
Needle Blight
,
Twig Blight
of chamaecyparis, retinospora,
cypress, bald cypress, arborvitae, juniper, yew,
and giant sequoia.
Pestalotia hartigii Associated with a basal stem
girdle of young conifers but parasitism not
proven. The stem has a swelling above the gir-
dling lesions, and the tree gradually turns yellow
and dies. The effect may be more from high
funerea
(see
▶
