Dactuliophora Leaf Spot
Dactuliophora elongata Leakey
Symptoms: Symptoms begin on the upper leaf surface as
pinpoint isolated brown lesions. As the lesions increase in size,
they become brownish at the edge and dirty white or straw colored
toward the center. In wet weather, irregular water-soaked areas
develop around the spots and turn necrotic. Well-developed lesions
have no definite shape or are roughly oval or semicircular, zonate
with kidney-shaped patches of necrotic tissue and brown or yellow
tissue in between. Black sclerotia develop in upper surface of
necrotic tissue.
Pathogen and disease characteristics: Tan aerial mycelium
without sclerotia develops on potato dextrose agar. On the host,
the white mycelium is appressed to the cuticle on the lower leaf
surfaces. Obclavate-ellipsoid to pyriform, brown sclerotia develop
on erumpent, cup-shaped sclerotiophores. Sclerotia germinate by
producing germ tubes over the entire surface after 4 to 8 hours.
Host range: Pearl millet.
Geographic distribution: Nigeria (Tyagi
1985), Mali, Niger (Wilson et al.,
in press).
Nomenclature discrepancies: Disease symptoms illustrated
in Williams et al. (1978) and attributed
to zonate leaf spot (Gloeocercospora sorghi) are probably
those of dactuliophora leaf spot.
Seed transmission: Not known to be transmitted by seed.
Primary citation: Tyagi 1985.
United States
Department of Agriculture
Agricultural
Research Service
The material on this page is in the public
domain.
Original posting: June 5, 1999.
|
previous page