Bacterial canker of mango, caused by the bacterium Xanthomonas citri subsp. mangiferae, poses a significant threat to mango cultivation worldwide. Diagnosing this disease accurately is a pivotal step in effectively managing its impact on orchards. A range of diagnostic methods is employed to identify the presence of the pathogen and confirm the disease's occurrence. These methods encompass both visual observations and sophisticated laboratory techniques, collectively providing a comprehensive understanding of the disease's prevalence and severity. Through these diagnostic measures, farmers and agricultural experts can make informed decisions to mitigate the disease's effects and safeguard mango production.

2. • Angular to irregular
lesions on leaves, dark
brown to black,
cankerous on lower side
but occasionally on both
the sides and surrounded
by chlorotic halo.
• Cankers on petioles are
raised and dark brown to
black in colour, while on
twigs and branches are
raised with longitudinal
fissures.
Lesions on fruits are
raised and dark brown to
black which gradually
develop in to cankers.
• Under favourable
condition lesions increase
in size and sometimes
cover complete fruit.
• Lesions often burst
extruding gummy
substances containing
bacterial cells of the
pathogen.
Fruits may drop off, if
infection comes at stem
end.
Xanthomonas campestris pv. mangiferaeindicae

4. Common
Methods
Used
in
Diag
Visual
Examination
Culture -
dependent
Methods
Serological
Methods
leaf spots, stem cankers, and fruit lesions,
which are indicative of bacterial canker disease.
isolate and identify the pathogen.
Antibody-based ELISA tests to identify bacterial
canker pathogens.
Grow bacteria obtained from diseased tissue
on selective media supplements to

5. Enzyme-linked Immunosorbent Assay
(ELISA)
What is
ELISA? Process
Result
ELISA uses specific
antibodies to detect
bacterial proteins present
in diseased host tissues
and can yield results
within a few hours.
Antibodies that bind to the
bacterial antigens are added to a
sample of the diseased tissue. If
bacterial canker is present, the
antibody will bind to the antigen,
producing a color change that
can be measured
spectrophotometrically.
The final result of ELISA
is a measure of the
amount of bacterial
antigen present in the
sample, which is used to
confirm the presence of
bacterial canker.

6. Challenges in Diagnosis
SymptomSimilarity SamplingTiming
The time of sampling
during the disease
development stage
can affect diagnostic
accuracy, making it
essential to sample
at the optimal time.
Limited
Compatibility
Current methods are
often not compatible for
detecting multiple
bacterial infections or the
pathogen in a mixed
infection, which can lead
to challenges in
diagnosis.
Many bacterial diseases
of mango have similar
symptoms, making it
difficult to differentiate
bacterial canker from
other diseases.

7. A promising new diagnostic method for bacterial
canker of mango involves using DNA sequencing to
identify the specific strain of bacteria causing the
disease. This method has shown great accuracy in
identifying the pathogen and could lead to more
targeted treatments.
Another new method involves using hyperspectral
imaging to detect changes in the reflectance of light
from infected leaves. This non-invasive technique
has the potential to quickly and accurately detect
the disease in large orchards, allowing for early
intervention and prevention of further spread.
•Early diagnosis and accurate identification of
bacterial canker pathogens are essential for
managing disease spread and reducing economic
losses in the mango industry.