Bacterial and phytoplasma diseases of gram and urd bean

1. Presented by
Fahnaz Sultana
2017-AMJ-105
Dept. Of Plant Pathology,AAU

2. GRAM OR CHICKPEA
 Gram (Cicer arietinum ), is reportedly
originated from western Asia
(Turkey).
 India is the largest producer,with
about 8 million tons, accounting
for about 67% of total world
production .
Economic Importance:
They are rich source of protein ( 17-20%) and form an
important part of vegetarian diet.
Source: Food and Agricultural Organisation (FAO)

3. Source: Food and Agricultural Organisation (FAO)

5. INTRODUCTION
• Bacteria are not major pathogens of gram
(chickpea) and urd bean.
• There are very few bacterial and phytoplasma
diseases reported for gram and urd bean and
only limited information is available describing
the symptoms produced, the causal agent,
disease cycle or management practices.

6. 1. Bacterial leaf blight :
Xanthomonas campestris pv. cassiae
SYMPTOMS:
occur at any stage of plant growth
 This disease is characterized by water-soaked
lesions on the radicle and young root tissue which
turns dark brown.
 Water-soaked lesions can also
appear on the leaf surface that
progress into dark brown lesions
with chlorotic halos.

7.  Petiole infections will result in brown lesions and
defoliation.
 Post emergence seedling rot is also common.

8. CAUSAL ORGANISM:
Xanthomonas campestris pv. cassiae is a Gram-negative, rod-
shaped bacterium approximately 0.8 x 1.4 μm in size .
DISEASE CYCLE :
• The pathogen survives on seed and plant debris and
spreads rapidly by rain splash, wind and irrigation water.
EPIDEMIOLOGY:
 Warm weather condition (28-32°C )
 Rainfall
 High humidity (70-90%).

10. MANAGEMENT:
 Use disease free seed.
 Use effective sanitation practices
 Destruction of plant debris and stubbles.
 Resistant variety
 Soak the seeds in 500 ppm Streptocycline solution
for 30 min before sowing followed by two sprays of
Streptocycline combined with 3 g of Copper
Oxychloride per litre at an interval of 12 days is
recommended.

11. 2. Bacterial Stem Canker:
Pseudomonas andropogonis
SYMPTOMS:
 Stem cankers, leaf spots and dieback are observed
on grams infected with Pseudomonas andropogonis.
 The infected plants will produce few blossoms
resulting in reduced pod set.
 Complete plant defoliation can be seen in severely
infected plants.

12. CAUSAL ORGANISM:
Pseudomonas andropogonis is a Gram-negative
rod approximately 0.6 x 1.6 μm in size.
• Warm, rainy and wet weather.
FAVOURABLE CONDITIONS:
***Infection of chickpea by P. andropogonis is not
common.

13. 3. Phyllody of gram:
 Phyllody is a minor problem in gram because of its
infrequent occurrence.
 The disease is caused by a leafhopper-transmitted
phytoplasma (formerly known as a mycoplasma-like
organism or MLO).
 Gram or Chickpea phyllody disease was first
reported in 1959 from Coimbatore in Tamil Nadu,
India.

14.  Phyllody means transformation
of floral parts into green leaf-like
structures (Figs. 1)
And this is the most
characteristic
symptom of the
disease. The normally
white to purple calyx of
flowers is small and
green or absent.
SYMPTOMS:
Fig. 1. Healthy and normal flowers (left)
and abnormal green structure (phyllody)
on right.

15.  If infection occurs
early, pods are not
produced after the onset
of infection.
If infection is late,
phyllody can be less
pronounced and small
sickle-shaped pods
(Fig 2).
Fig. 2. Healthy pod (left) and sickle
shaped pods (right).

16. Shriveled seed (Fig. 3) may also form.
 Infected plants are commonly stunted and bushy in
appearance and remain green after surrounding plants have
matured (Fig 4).
Fig. 3. Healthy seeds (left) and
abnormal degenerated seeds (right).
Fig. 4 stunted and bushy in appearance.

17. CAUSAL ORGANISM:
Phytoplasma ( formerly known as a mycoplasma-like
organism or MLO)
Fig. 5. Leafhopper Orosius albicinctus, vector
of gram phyllody
 Gram or Chickpea phyllody is caused by leafhopper
transmitted phytoplasma.
 The principle vector of gram phyllody in India and Pakistan
is Orosius albicinctus .

18. The disease agent can also be transmitted by grafting but is
not mechanically transmissible.
DISEASE CYCLE :
MANAGEMENT:
 Destroy weed reservoirs located near the crop to reduce
primary inoculum and discourage buildup of leafhopper
populations.
 Spraying systemic insecticides to eliminate leafhopper
colonization within the crop.
 The disease symptoms can also be suppressed by foliar
application of oxytetracycline hydrochloride solution (500 ppm)
at weekly intervals.

19. Urd bean

20. INTRODUCTION
In India, Total cultivated area 3.24 million hectare.
Production 1.82 million tonnes.
Average productivity 469 kg /ha.
***26 Per cent protein.
Source: Food and Agricultural Organisation(FAO)

21. SYMPTOMS:
 Common bacterial blight
affects mainly the foliage
and pods.
Symptoms initially appear
as small, water-soaked spots
(lesions) on the leaves
(Figure 1 ).
1. Common bacterial Blight:
Xanthomonas axonopodis pv phaseoli
Figure 1 . Water-soaked lesions

22. The lesions gradually
enlarge and coalesce into
irregular shapes ,
frequently one inch or
more in diameter, and they
exhibit a scalded
appearance.
The lesions may become
dry and brown and
surrounded by a narrow,
lemon-yellow-coloured
margin (Figure 2).
Figure 2. Mature common bacterial
blight lesions.

23. Infected pods may
exhibit circular, slightly
sunken, water-soaked
areas .
The infected areas on
the pods usually dry to
become reddish-brown
lesions.
Pod infections
frequently result in
discoloured
and shrivelled seeds.
Figure 3. Common bacterial blight on pods.

24. DISEASE CYCLE:
 The pathogen survives on seed and plant debris.
 Spreads rapidly by rain splash, wind and irrigation water.
EPIDEMIOLOGY:
 In general, pathogen causes most severe disease under
fairly warm temperature conditions ( 28-32 °C ).
 Also requires high rainfall
 Humidity (70-90%).

25. MANAGEMENT:
 Use disease free seed.
 Destruction of debris and stubbles.
 Seed treatment with bleaching powder and a spray
of stable bleaching powder (1000 ppm) is effectively
manage the disease.
 LGG 407, LGG 444, JAL 781 and ML 537 are tolerant
to this disease.

26.  Soak the seed in 500 ppm streptocycline
solution for 30 min. Before sowing followed
by two foliar sprays of plantomycine 100 mg
combined with 3 g of copper oxychloride per
liter of water at 12 days intervals.

27. Figure . Halo blight on leaves.
The first symptoms are
small, water-soaked lesions
resembling pinpricks on the
leaves.
 These spot progressively
turn dark brown and are
surrounded by a wide
greenish yellow halo.
2 Halo Blight
Pseudomonas syringae pv. Phaseolicola

28. Figure . Halo blight on bean pods.
Pod symptoms begin as
tiny, water-soaked spots
on the pod surface that
gradually enlarge to form
dark, sunken lesions .