Bacterial blight is a serious disease that affects pomegranate cultivation in India, which is caused by the bacterium Xanthomonas axonopodis pv. punicae. The disease can cause significant damage to pomegranate trees, leading to reduced yield (in some cases up to 90%) and poor fruit quality. This, in turn, can affect the marketing value of the fruits and lead to significant economic losses for farmers. Thus, effective disease management strategies are crucial for controlling bacterial blight in pomegranate and maintaining productivity.  

What causes Bacterial Blight Disease in Pomegranate? 

Bacterial blight disease is more severe during fruiting stage. The bacterium can survive on infected plant debris, in soil, and in plant tissue, and can be transmitted through various means as given below. 

• The bacterium can be spread from infected plant tissues to healthy tissues through splashing rain or irrigation water. 
• Natural openings and wounds can act as a source for bacteria entry. 
• Contaminated pruning tools, equipment and movement of workers may spread the disease over short distance. 
• Infected planting material such as seedlings or cuttings can serve as a means of introducing the bacterium to new areas. 
• Certain insects, such as thrips, blister beetles and whiteflies, can transmit the bacterium from infected to healthy plants while feeding. 
• Environmental factors such as high humidity (> 50%) and temperature (25 – 35°C) along with intermittent rainfall and cloudy weather can create favorable conditions for the growth and spread of the bacterium.  

Bacterial Blight in Pomegranate Symptoms: 

• Small, circular, water-soaked spots appear on the leaves, which later turn brown and necrotic. The spots may coalesce and form larger lesions. 
• In severe cases, the infected leaves may turn yellow and fall off the plant, leading to defoliation.  
• Infected twigs turn brown or black and may wilt, causing dieback of the affected branches.  
• Small, dark, sunken spots appear on the fruit surface, which can enlarge, cover the whole fruit surface and cause the fruit to crack or split open. 
• The bacteria can cause the formation of gum-like exudates on the surface of infected tissues.  
• Infected fruits may show internal discolouration due to rotting.  

Bacterial Blight in Pomegranate Preventive Measures: 

Cultural:

• Use disease-free planting material. 
• Use disinfectant pruning tools and equipment. 
• Remove and destroy infected plant parts. 
• Avoid overhead irrigation to reduce the spread of the disease. 
• Ensure proper spacing between plants to promote good air circulation. 
• After harvesting during Dec – Feb, prune the secondary and tertiary branches with infection. 
• Apply the recommended dosage of fertilizers and incorporate well-decomposed farmyard manure and vermicompost along with it to enhance the resistance of plants against diseases. Application of manures and fertilizers during the rest period is also important. 

Biological:

• Apply Biocontrol agents such as Pseudomonas fluorescens (10 ml/lit water) or Bacillus sp (250 ml + 10 kg FYM/Compost) and Trichoderma sp (1 – 2 kg + 100 kg FYM) as a prophylactic measure.  
• Give a spray of 40% Tulsi extract followed by neem oil spray. 
• The extracts of garlic bulb, meswak stem, and patchouli leaves at a concentration of 30% can be sprayed. 
• Spray Geolife Geomycin Bio Bactericide at 0.5 – 1 gm/lit water or Terra BactoKill.at 3 ml/lit of water. 

Chemical (Prophylactic Measure):

• To reduce the severity of the disease, apply a 1% Bordeaux mixture by spraying prior to pruning. 
• Smear application of copper-based fungicides onto the surface of the plant parts susceptible to infection, such as the basal trunk, branches and twigs, before the onset of disease symptoms helps to control the disease. 
• For this, following pruning, apply Streptocyclin or Streptomycin sulphate (0.2 gm/lit water) or Bactinash (0.5 gm/lit water) + Copper oxy chloride (2 gm/lit water) to the basal trunk of susceptible plants to decrease the occurrence of the disease.  

(Note: Always prepare Bordeaux mixture fresh and use on the same day) 

Management of Bacterial Blight in Pomegranate:  

In order to effectively manage bacterial blight in pomegranate, it is recommended to implement an integrated approach that combines preventive measures with other methods, as relying solely on chemical control is ineffective. 

The below mentioned chemicals can be used alone or in combinations.  

(Note: After application of bactericide, spray General liquid micronutrient (2.5 ml/lit of water). It helps in effective management of the disease and also increases plant’s resistance against the disease. Also, check the product’s label to know the right time of application) 

Click Here to Discover More: Effective Strategies for Managing Bacterial Leaf Blight in Rice/Paddy

Bhendi (Abelmoschus esculentus), also known as okra or lady’s finger, is a popular vegetable that is widely grown and consumed in India. Like any other crop, bhendi is also susceptible to various diseases like fusarium wilt, powdery mildew, leaf spot and yellow vein mosaic virus. that can affect its growth and yield. Among these, yellow vein mosaic or vein-clearing is the most devasting viral disease in all bhendi growing regions of India. If the crop is affected by the virus at early stages, up to 80% of crop loss can be expected. 

Yellow Vein Mosaic in Bhendi 

The virus can infect plants at any growth stage. The infections are more prevalent during the summer months when the incidence and infestation of whiteflies are more severe.  

Causal organism: Bhendi Yellow Vein Mosaic Virus 

Vector: Whitefly (Bemisia tabaci) 

Symptoms of Yellow Vein Mosaic / Vein Clearing in Bhendi:

• Yellowing of veins and veinlets of the leaves. 
• Later, interveinal regions of the leaves turn yellow or white. 
• The leaves of the infected plant may show mosaic patterns of yellow and green. 
• In case of severe infection, affected young leaves show complete chlorosis. 
• The infected plants may show stunted growth and reduced size. 
• The leaves may be smaller in size and may show distortion or curling. 
• Affected plants may produce fewer flowers and fruits, and the fruits may be deformed, smaller in size, harder and yellow green in colour.

Preventive Measures: 

There are no known treatments for yellow vein mosaic virus, once a plant is infected. However, a combination of preventive measures and control strategies can be effective in managing the disease and minimize crop loss.  

• Use Yellow Vein Mosaic Virus (YVMV) tolerant varieties/hybrids of bhendi like Rudraksh F1 Roshani Okra, Urja Agri – Bhindi Marina, Sarpan F1 hybrid bhindi, Indam 9821 bhendi, Pan 2127 hybrid bhendi. 
• Avoid growing susceptible varieties during summer, since whitefly activity is high during the season.
• Remove and destroy the disease affected plants from the field to avoid secondary spread.
• Keep the field clean and free from weeds. 
• Control the population of whiteflies and prevent the spread of the virus. 
• Introduce natural predators of whiteflies, such as ladybugs and lacewings, to control their populations. 
• Avoid excessive use of ammoniacal nitrogen fertilizers as it can increase the susceptibility of plants to viral infections. 
• Plant leguminous crops like beans or lentils in rotation with bhendi to improve soil health and reduce the risk of disease transmission. 
• Plant marigold, maize or sunflower as border crops to trap the vector, whitefly. 
• Spray chilli and garlic extracts to repel whiteflies. 
• Give foliar spray of Magnum Mn and Geo life No Virus to enhance the plant’s resistance to YVMV and reduce the incidence of the disease. 
• Crop rotation with non-host crops. 
• Installation of yellow sticky traps @ 6-8 per acre. 

Control Measures for Vector, Whitefly: 

Discover more about diseases and insect-pests affecting okra: symptoms and control measures. CLICK HERE

Bitter gourd (Momordica charantia), also known as bitter melon, is a tropical and subtropical vine that is widely grown for its edible fruit. It is an important vegetable crop in many regions of the world, including India. It belongs to the family of cucurbits that includes several other commonly grown vegetables such as cucumbers, pumpkins, squash and melons. Like other cucurbits, bitter gourd is also vulnerable to a range of diseases that can cause significant yield losses if not managed effectively. Bitter gourd diseases can be caused by bacteria, fungi, viruses and other pathogens and can affect all parts of the plant, including the leaves, stems, flowers and fruits. Effective management of bitter gourd diseases includes understanding of the diseases that affects the crop, their symptoms and the methods to control them.

1. Powdery Mildew

Causal organism: Podosphaera xanthii (formerly Sphaerotheca fuliginea) 

Powdery mildew is a common fungal disease in bitter gourd diseases. Its pathogen thrives in warm and humid conditions and can spread quickly in crowded plantings. 

Symptoms:  

• Presence of white powdery residue on upper surface of the leaves, stems and other growing parts. 

  

• The leaves of the infected plant may start turning yellow or brown, especially in areas with heavy fungal growth. 
• Eventually, it leads to drying and falling of leaves. 
• Infected leaves may shrivel and become distorted or misshapen. 
• Plants show stunted growth due to decreased photosynthesis caused by fungal growth. 
• Infected plants may produce smaller and less flavorful fruit. 
• In severe cases, the entire plant may be covered with the powdery growth, leading to the death of the plant. 

Management of Powdery Mildew in Bitter Gourd:  

2. Downy Mildew

Causal organism: Pseudoperonospora cubensis 

Downy mildew is favoured by cool, moist conditions and can spread rapidly in humid environments. 

Symptoms:

• Appearance of yellow angular patches or spots on the upper surface of the leaves. 
• As the disease progresses, brown spots may develop on the infected leaves, often surrounded by a yellow halo. 
• Under moist conditions, fuzzy grayish-white water soaked lesions appear on the underside of the leaves. 
• Causes rapid defoliation of affected leaves. 
• Affected plants becomes stunted and kills the plants in severe cases. 

Management of Downy Mildew in Bitter Gourd: 

3. Anthracnose

Causal organism: Colletotrichum spp. 

Warm and humid conditions provide favorable conditions for the growth and spread of the fungus that causes anthracnose. 

Symptoms:  

• Dark, sunken lesions develop on the leaves, stems and fruits of the bitter gourd plant. 
• These lesions or spots may be circular, oval or irregular. 
• As the infection progresses, small black spots/flecks may appear scattered on the affected parts. 
• Infected leaves may wilt, dry and fall off. 
• Petioles and stems may develop elongated dark spots with light centers, which can cause the death of surrounding tissues. 
• When the lesions on the stem base enlarge, it causes wilting and lodging of plants. 

Management of Anthracnose in Bitter Gourd: 

4. Angular Leaf Spot (Bacterial Disease)

Causal organism: Pseudomonas syringae 

The disease can be transmitted through contaminated seed, infected plant debris, or by wind-driven rain. Warm and humid weather conditions are conducive to disease development and once established, the disease can spread rapidly. 

Symptoms: 

• Appearance of small, angular, water-soaked lesions on the leaves which later expand rapidly under favorable conditions. 
• As the disease progresses, the lesions turn brown and necrotic, with a dark brown center and yellowish margins. 
• Affected leaves shrink and often tear away healthy leaf tissue forming irregular holes giving ragged appearance. 
• The disease can also affect other plant parts, including stems, fruits and tendrils. 
• Infected fruits will be small with circular spots. 

Management of Angular leaf spot in Bitter Gourd: 

5. Fusarium Wilt

Causal organism: Fusarium oxysporum f. sp. niveum 

It is caused by the soil-borne fungus which can infect the plant at any stage of its growth, but symptoms are most pronounced in the mature stage. The fungus can be spread through contaminated soil, water, and infected plant debris. Warm and humid weather conditions can also increase disease incidence. 

Symptoms: 

• Leaves of the affected plants show yellowing and drooping symptoms. 
• Infected plants may start to wilt, particularly during the hottest part of the day and may not recover even after watering. 
• The stem of the infected plant may show a brown discoloration, particularly at the base, which can progress upward. 
• Infected plants may exhibit dark brown or reddish-brown discoloration of the vascular tissue when the stem is cut open. 
• The plant shows stunted growth and later dies.  

Management of Fusarium Wilt in Bitter Gourd: 

6. Cercospora Leaf Spot

Causal organism: Cercospora citrullina 

The disease is most common in hot and humid regions. The fungus thrives in crop debris and weeds. Their spores can transmit through rain splashes, wind and tools/implements. 

Symptoms: 

• Small, circular or irregularly shaped spots appear on the leaves. 
• The spots are usually brown or gray in the center and have a yellow or reddish-brown border. 
• Under warm and humid conditions, the spots on the leaves may grow and merge, forming larger lesions that can cover most of the leaf surface. 
• The infected leaves may start to turn yellow or brown around the spots, and then dry up and fall off. 
• Causes premature defoliation of leaves. 
• In some cases, the disease can also cause dark, sunken lesions on the fruit, which can reduce the quality and yield of the crop. 

Management of Cercospora leaf spot in Bitter Gourd: 

7. Mosaic Disease

Causal organism: Cucumber mosaic virus (CMV) / Papaya ringspot virus (PRSV) 

Vector: Aphids 

This viral disease is transmitted by vector and by mechanical mechanical inoculation of plant sap. High temperatures and low humidity can increase the replication and spread of the virus. 

Symptoms:

• Appearance of alternate light and dark green (mosaic) patches on the leaves. 
• Reduction in leaf size. 
• The leaves may be distorted, wrinkled, or twisted. 
• Affected plant’s growth is inhibited thus giving bushy appearance.
• The fruits may develop raised bumpy protrusions that can make them unmarketable. 

Management of Mosaic Disease: 

The disease can be controlled by managing the vector, aphids which spreads the virus. In addition to spraying insecticides, spray Geolife No Virus at 3 – 5 ml/lit water which helps to increase plant’s resistance to the disease. 

(NOTE: Check the product label to know the right time of application) 

ITK Practices to control Diseases in Bitter Gourd 

• Spraying neem oil can control Powdery mildew, Downy mildew and anthracnose. 
• Sprinkling ash over the plants can help to control powdery mildew. 
• Buttermilk Fungicidal spray: 250 – 500 ml of 15 days fermented buttermilk + 15 liters of water can be used as foliar spray to control fungal diseases. 
• 20 gm of ginger powder mixed in 1 liter of water can be sprayed at an interval of 15 days. It is effective in checking the incidence of powdery mildew and other fungal diseases.  
• Leaf extract of Prosopis juliflora can be sprayed to control leaf spot and powdery mildew. 
• Following crop rotation with non-host crops like legumes or corn to reduce pathogen buildup in the soil. 

Discover effective strategies to protect your gourd crops from downy mildew and boost your yield. CLICK HERE