1. Yellow vein mosaic virus infects okra and is transmitted by whiteflies. It causes yellowing of veins and stunting. Controlling whiteflies through insecticides can help manage the disease. 2. Root-knot nematodes infect okra and cause galls or knots on roots, reducing plant growth. They are soilborne and favor warm temperatures. Crop rotation, solarization, and nematicides can control them. 3. Fusarium wilt of okra is caused by a soilborne fungus and leads to wilting and death. Using resistant varieties, crop rotation, and fungicides can manage this disease.

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.