Litchi Physiological disorders A Lecture By Allah Dad Khan To FFS Trainee

2. Lychee Physiological Disorders
A
Lecture To ToT trainees ( FFS)
By
Mr. Allah DadKhan
Provincial Coordinator IPM KPK
MINFAL Pakistan

3. Pericarp Browning
 Browning of the pericarp
occurs at ambient
temperatures of 20-30°C
within 24 hours of harvest.
Water loss (desiccation) of
litchi results in brown spots
on the bright-red shell
(pericarp). Under severe
conditions or prolonged
exposure, packaging in
polymeric films reduces
water loss and browning
severity
Symptoms Fruit Cracking

4. Fruit cracking
 Fruit cracking is one of the major limiting factors in the
cultivation of lychee, especially early cultivars (Singh,
1986). The early varieties are more prone to the
problem of fruit cracking in comparison to late
cultivars. The low atmospheric humidity, high
temperature and hot winds during fruit development
and maturity stage favour fruit cracking. Light irrigation
to maintain soil moisture and to improve humidity has
been found to minimize this problem through
maintenance of a better micro-climate. Mulching with
farm residues and 3 irrigations significantly reduced
the cracking (Singh, 1986) in a trial conducted on the
cultivar Shahi. In addition, spraying with either 100
ppm NAA or 0.2 percent borax during the developing
stage of the fruits has been found to be highly
effective in checking the cracking.

5. Pericarp Browning.
 Water loss (desiccation) of lychees results in
brown spots on the bright-red shell (pericarp).
Under severe conditions or prolonged
exposure, the spots enlarge and coalesce until
the surface is completely brown. The flavor of
the arils within browned fruit may or may not
be adversely affected. Packaging in polymeric
films reduces water loss and browning
severity.

6. Chilling injury.
 Symptoms include pericarp browning (similar
to that caused by water loss) and increased
susceptibility to decay. Storage at 1°C (34°F)
for 12 days before transfer to 20°C (68°F) for
one day resulted in pericarp browning

7. Pericarp split (cracking).
 Incidence and severity of cracking depend on
cultivar and desiccation during storage. Cracks
provide an entry way for decay-causing
pathogens.

8. Aerial Breakdown
 Prolonged storage and overmaturity may
cause aril breakdown (softening, loss of
turgidity, translucency) and loss of flavor
beginning at the blossom end and spreading
to the stem end.