Download Blight - CocoaSafe

BLIGHTS
IMPORTANCE
Hawar bebenang hitam or horse hair blight (Marasmius crinis-equi) is of little economic significance
on cocoa, and is not known to cause noticeable crop loss. The disease is generally associated with
poorly maintained trees.
Hawar bebenang putih or white thread blight (Marasmiellus scandens) is of little economic
significance on cocoa when it is kept under control. The disease is associated with poorly maintained
plants already weakened by poor field management, other pests and diseases. The disease can
usually be adequately controlled using cultural methods.
DESCRIPTION
HORSE HAIR BLIGHT
Hawar bebenang hitam forms an irregular
network of black mycelial hair-like strands
entangling the leaves of the branches. These
strands are loose hanging from branches or
leaves. Leaves that are so entangled are easily
detached.
THREAD BLIGHT
Hawar bebenang putih fungus forms a network of
white mycelial strands that grow across the
leaves, petioles and branches. The infected
leaves are shed from the branch and are held
together by the fungal threads and dense
mycelial pads.
ECOLOGY
On cocoa, horse hair blight is similar to white
thread blight, the disease is more common in
unattended fields where field sanitation practices
are poor and infrequent. The likely means of
spread of the disease are through fallen infected
twigs and spores of the fruit bodies.
The fungus fruiting bodies are produced during
long periods of continuous rains, sometimes in
chains along the black strands. Fruiting bodies or
basidiomata are small with the upper surface a
light brown and growing from the branch or on
short black stalks.
The occurrence of white thread blight is higher in
plantations with poor cultural practices, especially
when the normal rounds of sanitation pruning are
not maintained and shade is too dense.
The disease spreads mainly by the fungus
threads (hyphae) growing from leaf to leaf or
along branches within a tree, and from tree to
tree through infected fallen branches from tall
shade trees. The disease also spreads through
airborne basidiospores released from
basidiomata formed during wet weather.
The disease might also be spread by a
hemipteran bug, Usingeria mirabilis.
MANAGEMENT
These minor diseases only become a problem if cocoa orchards are neglected or poorly maintained.
The disease is associated with poorly maintained plants already weakened by poor field management
and other pests and diseases.
Both diseases are adequately controlled through regular sanitation pruning rounds. Infected and
dead branches must be removed from the canopy.
CROP LOSSES
Horse hair blight is of little economic significance on cocoa, and is not known to cause noticeable crop
loss.
White thread blight is of little economic significance on cocoa when it is kept under control.
PREFERRED SCIENTIFIC NAME
Marasmius crinis-equi F. Mueller ex Kalchbr
Horse hair blight; Hawar bebenang hitam
Marasmiellus scandens (Massee) Denis & D.A. Reid
Thread blight; Hawar bebenang putih
Taxonomic position
Domain: Eukaryota
Kingdom: Fungi
Phylum: Basidiomycota
Subphylum: Agaricomycotina
Class: Agaricomycetes
Subclass: Agaricomycetidae
Order: Agaricales
Family: Marasmiaceae
Domain: Eukaryota
Kingdom: Fungi
Phylum: Basidiomycota
Subphylum: Agaricomycotina
Class: Agaricomycetes
Subclass: Agaricomycetidae
Order: Agaricales
Family: Marasmiaceae
DISTRIBUTION MAP
Horse hair blight (Marasmius crinis-equi)
White thread blight (Marasmiellus scandens)