MAJOR DISEASES IN BHENDI

27 मई 2025

1. Cercospora leaf spot : 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.

Mode of spread and survival:

Management

2. Fusarium wilt: Fusarium oxysporum f.sp. 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.

Management

3. Powdery mildew: Erysiphe cichoracearum

Symptoms

The disease is found mainly on the older leaves and stems of plants. Yields of many of the infected vegetables are reduced due to premature foliage loss.
Increased humidity can increase the severity of the disease, and infection is enhanced during periods of heavy dew.
The disease symptoms appear as subtle, small, round, whitish spots on leaves and sometimes stems.
The spots enlarge and coalesce rapidly and a white mass resembling talcum powder becomes evident on the upper surface of older leaves or other plant parts. Young leaves are almost immune.
A large part of the talc-like powder on the leaf surface is composed of spores. These spores are easily blown by winds to nearby susceptible plants.
Heavily infected leaves become yellow, then become dry and brown. Extensive premature defoliation of the older leaves can ensue if the disease is not controlled.

Management:

Healthy, vigorous leaves and stems are less prone to infection.
Plants under nutritional stress in most cases will develop powdery mildew much sooner than plants the same age grown under a good nutritional program.
Hence the plant should be well manured and application of fertilizers should be done on the basis of standard recommendations.
Application of Wettable Sulphur (0.2%) or Bavistin (0.1%) or at an interval of 1 week interval effectively controls the disease.

4. Vein Clearing or Yellow vein mosaic

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.
The veins of the leaves will be cleared by the virus and intervenal area becomes completely yellow or white.
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.
The affected plants produce fruits with yellow or white colour and they are not fit for marketing.
The virus is spread by whitefly.

Management

Spray azadirachtin 0.03 WSP @ 5 g/10l or methyl demeton 25 EC @ 1.6 ml/l or thiamethoxam 25 WG @ 2 g/lit to kill the insect vector, whitefly.
By selecting varieties resistant to yellow vein mosaic like Parbhani Kranti, Arka Abhay, Arka Anamika, and Varsha Uphar, the incidence of the disease can be minimised.
The virus is transmitted by the whitely (Bemisia tabaci,.
Parbhani Kranti, Janardhan, Haritha, Arka Anamika and Arka Abhay can tolerate yellow vein mosaic.
For sowing during the summer season, when the whitefly activity is high, the susceptible varieties should be avoided.
Synthetic pyrethroids should not be used because it will aggravate the situation.
It can be controlled by application of Chlorpyriphos 2.5 ml + neem oil 2 ml lit of water.
For effective control of whiteflies we can use bio pesticides like Dr.Eliminator 250ml/acre.

5.Damping Off (Pythium sp., Rhizoctonia sp.):

Cool, cloudy weather, high humidity, wet soils, compacted soil, and overcrowding especially favor development of damping-off.
Damping-off kills seedlings before or soon after they emerge. Infection before seedling emergence results in poor germination.
If the decay is after seedlings emergence, they fall over or die which is referred to as "damp-off." The destructiveness of the disease depends on the amount of pathogen in the soil and on environmental conditions.
Seedlings that emerge develop a lesion near where the tender stem contacts the soil surface. The tissues beneath the lesion become soft due to which the seedlings collapse.

Management

Excessive irrigation should be avoided to reduce humidity around the plants.
Seed treatment with antagonist fungal culture of Trichoderma viride (3-4 g/kg of seed) or Thiram (2-3 g /kg of seed) and soil drenching with Dithane M 45 (0.2%) or Bavistin (0.1%) affords protection against the disease.
The field should be regularly inspected for the disease-affected seedlings. Such seedlings should be removed and destroyed.

6.Enation Leaf Curl of Bhendi:

The natural transmission if the disease occurs through whitefly. The disease symptoms appear prominently on the lower surface of the leaf as small, pin head enations.
These later on become warty and rough textured. Size of the leaf is reduced. The most characteristic symptoms of the disease are twisting of the main stem and lateral branches along with enations.
The bending of the plants is so severe that the entire plant appears to be creeping on the soil surface. Twisting of leaf petiole is conspicuous. The leaves become thick and leathery in structure. In case of heavy infection the newly emerged leaves also exhibit bold enations, thickening and curling. Fruits produced on the infected plants are few and deformed.

Management

Removal and destruction of virus affected plants reduces the disease incidence.
Controlling the whitefly population minimizes the incidence of YVMV. 4-5 foliar sprays of Dimethoate (0.05%) or Monocrotophos (0.02%) at an interval of 10 days effectively controls the whitefly population.
For effective control of whiteflies we can use bio pesticides like Dr.Eliminator 250ml/acre.

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