Longan diseases By Allah Dad Khan Provincial Coordinator IPM KPK MINFAL

2. Longan Diseases
A
Lecture To ToT trainees ( FFS)
By
Mr. Allah Dad Khan
Provincial Coordinator IPM KPK
MINFAL Pakistan

4. Anthracnose Colletotrichum gloeosporioides
Symptoms
 Anthracnose attacks both
leaves and fruit of the lychee
tree. However, fruit of the
lychee variety 'Mauritius' is
more susceptible to
anthracnose than is the fruit of
the 'Brewster' variety. The
lychee fruit is susceptible to
anthracnose infection from
blossom until the fruit is half-
grown. Most of the decay on
mature lychee fruit is from latent
infection when the fruit is small.
The small spots coalesce into
large brown spots as the fruit
ripens. A white mycelial mat
grows over the fruit during
storage

5. Stem Canker Caused by Botryosphaeria sp
Symptoms
 This fungus is normally
found attacking the
terminal branches of the
lychee tree. Signs of
infection include sunken,
shrinking, oval to
irregular lesions, which
may crack and expose
wood. The fungus is
managed by pruning out
infected branches and
limbs.

6. Pink Limb Blight Caused by Erythricium
salmonicolor
Symptoms
 This pathogen attacks
the limbs and trunk of the
lychee tree. The fungus
grows above and below
the bark. The outer layer
appears light pink to
white. The fungus
encircles the plant part
and girdles the vascular
tissue, causing foliage
wilt and death. This
fungus is also managed
by pruning exposed
wood

7. Algal Spot Caused by Cephaleuros virescens
Symptoms
 Algal spot has a wide host
range among tropical trees,
including both lychee and
longan trees. Lesions on leaves
are roughly circular, raised, and
greenish-gray in color. The alga
will eventually produce rust-
colored, microscopic 'spores' on
the surface of the leaf spots,
giving the spots a reddish
appearance. The alga may also
spread to branches. If branch
splitting occurs, the branches
may become girdled and die.
Algal spot seems to flourish in
groves that are treated with
organic fungicides, rather than
with copper-based compounds

8. Parasitic lichen Strigula sp
Sympodium
 Parasitic lichen may
parasitize leaves on the
longan. Symptoms include
white star-shaped spots on
leaf surfaces. This lichen
colonizes leaves reducing
their ability to
photosynthesize. Please
contact your local County
Cooperative Extension
 Service for current control
recommendations.

9. Brown blight
Symptoms
 Brown blight, Peronophythora
litchii, is a major disease in both
lychee and longan in China and
Thailand, although more
important in the former. It is also
reported to affect lychee in
India. It is well described in
Guangdong, and attacks leaves
and panicles, as well as fruit
that can be infected right up to
harvest. These infections all
reduce production and shelf life.
Flower panicles are particularly
susceptible. Immature fruit turn
brown, while those infected
before harvest have a white
mildew growing on the skin.

10. Tree Decline
Symptoms
 The symptoms include a
sudden branch wilt that is
followed by the decline of
new growth on the
affected branch over a
period. In other
situations, the tips die
without wilting. The tree
or branch may recover
temporarily, but
subsequently dies. Parts
of the tree flush and
grow, while other
sections die.