My Email Id : dineshdalvaniya@ymail.com My Mob. no: 09574031169

2. Pl. Path. -508
(Diseases of Vegetables and Spices Crops)
SUBMITTED BY:
Dinesh Dalvaniya
Reg.no:04-00876-2011
M.sc.(Agri.) 2nd Sem
Ag. Entomology

3. DISEASES OF OKRA
5.Yellow vein mosaic
7. Root-knot
9.Wilt
11.Cercospora leaf spot
13.Powdery mildew

4. 1. Yellow Vein Mosaic
 C.O.:- Virus (Yellow Vein Mosaic virus)
 Transmission: By vector – White fly
 Symptoms
 Yellowing of the entire network of veins in the
leaf blade is the characteristic symptom.
 In severe infections the younger leaves turn
yellow, become reduced in size and the plant is
highly stunted.
 In a field, most of the plants may be diseased
and the infection may start at any stage of plant
growth.
 Infection restricts flowering and fruits, if
formed, may be smaller and harder.

6. • Diseases cycle
Diseases
Secondary inoculum
Host • through vectors
Season
Favorable condition Off season Primary inoculum
• wild hosts
Temp. > 32-40 0C,
Less relative
Humidity ( < 60 % )

7.  Control
• The virus is transmitted by the whitefly (Bemisia
tabaci), So control of this pest will gives better
results.
• Parbhani Kranti, Janardhan, Haritha, Arka Anamika
and Arka Abhay can tolerate yellow vein mosaic.
• Spraying monocrotophos 1.5 ml/litre of water can
restrict the disease spread.
• It can be controlled by application of Chlorpyriphos
2.5 ml + neem oil 2 ml/lit of water.

8. 2 Root Knot
 C.O.:-Meloidogyne incognita & Meloidogyne javanica
 Symptoms
• Above ground symptoms:
• Plant shows unthrifty development and stunted growth.
• The leaves are yellowish green to yellow and tend to
dropping and then there will be a wilting.
• Below ground symptoms:
• The most characteristics symptoms of the disease is the
formation of knots or galls on the root .

10.  The main root and laterals bear spherical to elongated
various size of galls.
 In some cases the plants would show chlorosis but
rarely do the plants die from nematode infection.
 Disease cycle:
 Each female lays approximately 500 eggs in a
gelatinous matrix produced by female.
 First and second stage juveniles (Larvae ) are worm
like and develop inside each egg.
 The second stage juvenile emerges from egg into the
soil.
 The nematode than enter under third and forth moult.
 Fourth stage continues to grow in thickness and
become adult female, which appear pears like shape.

11.  Favourable conditions :-
• Egg larvae develop in 16 days at 270C temperature
and 80 days at 140C temperature.
• Nematode female favours 25-280C.
• Sandy light soils favours their movement.
• High temp. such as 40-500C kill these larvae quickly.
• In general, the temperature of 25-280C are best for
infection, rapid multiplication and increased size of
galls.

12.  Control
• Follow crop rotation and elimination of weed host.
• The addition of non-edible oil cakes like castor cake/
mustard cakes @2.5 t/ha.
• Summer deep ploughed
• Flooding is effective to minimize the disease.
• Soil solarization with 100 gauge (25µm) LLDP
plastic covering during April-May for 15 days.
• Soil application of carbofuran (3G) @33kg/ha or
phorate (10 G) @ 10 kg/ha in furrow.

13. 3. Wilt Of Okra :
 C.O.:- Fusarium vasinfectum
 Symptoms
 The conspicuous symptom is a typical wilt, beginning
with a yellowing and stunting of the plant, followed
by wilting and rolling of the leaves as if the roots
were unable to supply sufficient water.
 Finally, the plant dies.
 If a diseased stem is split lengthwise, the vascular
bundles appear as dark streaks.
 When severely infected, nearly the whole stem is
blackend.
 The fungus has mostly three-septate spores.

15. • Diseases cycle
Diseases
Secondary inoculum
Host • Through water
• Irrigation rain
Season
Favorable condition Off season Primary inoculum
• Soil borne
 Temperature range of • Diseased plants
54 to 100°F, with the
optimum at 77°F.

16.  Control
• A better plan is to use a 6-year rotation before the
fungus is destructive; this permits many years of okra
growing without too much loss.
• Drench the field with Copper oxychloride @3g/litre
of water.
• Treat the seeds with Carbandazim or Mancozeb @
3g/kg seed.
• Grow resistant varieties like Pusa Makhamali, Okra
I.S. 9273, 9857, C.S. 3232, 8899, I.S. 6653, 7194 and
Pusa Sawani.

17. 4. Cercospora Leaf Spot
 C.O.:- Cercospora malayensis & C. abelmoschi
 Symptoms
• In India, two species of Cercospora produce leaf
spots in bhendi.
• C. Malayensis causes brown, irregular spots and C.
abelmoschi causes sooty black, angular spots.
• Both the leaf spots cause severe defoliation and are
common during humid seasons.
• The fungi survive through conidia and stomata on
crop residue in soil.

19. • Diseases cycle
Diseases
Secondary inoculum
Host • air borne conidia
Season
Favorable condition Off season Primary inoculum
• plant debris
•High humidity • Infected plants
•Low temperature
•More application of N
&P

20.  Control
• Spraying Mancozeb or Zineb 2 g or Carbendazim 1 g/
litre can control the disease.
• They can be controlled by spraying Bordeaux mixture
(1 per cent) or Diathane M-45 (0.2 per cent), starting
from about a month after sowing and repeating at
fortnightly interval, depending upon the severity of
the disease incidence.

21. 5. Powdery Mildew :
 C.O.:- Erysiphe cichoracearum
 Symptoms
• Powdery mildew is very severe on bhendi.
• Greyish powdery growth occurs on the under as well
as on the upper surface of the leaf causing severe
reduction in fruit yield.

23. • Diseases cycle
Diseases
Secondary inoculum
Host • air borne conidia
Season
Favorable condition Off season Primary inoculum
• plant debris
•Temp. 28 oC,
• Dry weather condition
(< 60 % RH)
•cloudy weather favours
the disease
development.

24.  Control
• The disease is effectively controlled by dusting finely
ground sulphur at 30 kg/ha or spraying wettable
sulphur 3 g/litre of water or Dinocarp 1 ml/litre of
water three to four times at 15 days intervals.
• Karathane (0.03 per cent) and Bavistin (0.2 per cent)
are also effective.