“Chlorosis of leaf margins, wilting, oozing of gum, cracking of fruits” – Are you seeing these signs in your cucurbits farm?
If yes, it’s high time to take immediate action against this highly destructive fungal disease: gummy stem blight. This fungus has the ability to spread rapidly, causing significant damage and loss to your crops. Visualize the devastating consequences of allowing this disease, caused by the pathogen Didymella bryoniae, to go unchecked. It can lead to substantial yield losses and a decline in fruit quality.
Whether you’re already engaged in cucurbit farming, or if you’re planning to venture into it, it is crucial to familiarize yourself with the signs and causes of gummy stem blight and equip you with the tools to safeguard your harvest.
Symptoms of Gummy Stem Blight in Cucurbits
Gummy stem blight symptoms can be observed on all parts of the plant except the roots.
Leaves:
- Initially, water-soaked leaf spots can be seen, particularly near the leaf margins where chlorosis (yellowing) may also be observed.
- Infections can occur on young seedlings, presenting light to dark brown spots on the cotyledons.
- These spots may expand, merge together and result in leaf blighting and wilting.
Stems:
- If the infection occurs in the nursery, it can cause stem splitting, wilting and under severe conditions, the affected seedlings die.
- On the stems, the infection appears as brown water-soaked lesions that develop into stem cankers. These cankers exude a gummy brown fluid.
Fruits:
- Fruits of affected plants show cracking and rotting symptoms.
- Additionally, they may exhibit a characteristic black rot, which manifests as rotting with a black color.
Causes of the disease
Following are the conditions which create favourable conditions for the disease to develop and spread;
- High humidity levels of around 85% and moist conditions, especially with frequent rains or overhead irrigation and poor drainage.
- Infected seeds used for planting.
- Wind and rain splashes facilitating the disease’s dissemination within and between fields.
- Undecomposed plant material provides reservoir for fungus survival.
- Alternate host plants and weeds.
- Contaminated tools, equipment or even through clothing of farm workers.
Ways to Prevent Gummy Stem Blight in Cucurbits
- Use disease free healthy seeds from reputed source. Treat the seeds before sowing to avoid infection.
- Take proper precaution measures during nursery, by cleaning and disinfesting the growing area regularly and inspecting seedlings for at least every 2 days for any signs of spots/patches and remove all infected seedlings and burn.
- Deep plough the soil during summer to expose and kill the fungal spores.
- Keep the field free from weeds.
- Avoid overcrowding of plants for allowing proper penetration of air and sunlight.
- Avoid overhead irrigation to avoid wetting of leaves and spreading of fungal spores to other healthy plants.
- Rotate the crop every 2 years with non-host crops like Brassicas, onion and legumes.
- Avoid any damage to the plants as well as fruits to avoid entry of fungus through wounds.
- Collect and burn all the plant debris after harvest.
Management of Gummy Stem Blight in Cucurbits
1. Biological Management
Spray or drench with Trichoderma viride or Pseudomonas or Bacillus spp, 15 days after sowing at every 15 days interval to prevent and manage gummy stem blight disease in melons and other cucurbits.
| Product name | Technical content | Dosage |
| Anand Dr Bacto’s Fluro | Pseudomonas fluorescens | Foliar: 2.5 ml/lit of water
Drenching: 10 ml/lit of water |
| Multiplex Nisarga | Trichoderma viride | Foliar: 3 gm/lit of water
Soil Application: 1 – 2 kg of the product + 100 kg of FYM |
| Mildown Bio Fungicide | Bacillus subtilis | Seed treatment: 0.15 – 0.2 ml/kg seed
Seedling treatment/nursery bed: 5 ml/lit Drip: 2.5 ml/lit of water |
| Multiplex Bio-Jodi | Bacillus spp. & Pseudomonas spp | Foliar: 5 gm/lit of water
Soil Application: 2 – 5 kg of product + 120 – 150 kg of FYM |
2. Chemical Management
It is recommended to apply fungicides preventively in combination, about 1 week after germination or when the plants have 3-4 leaves to minimize crop damage and losses to a greater extent. As a curative measure, spray fungicides after disease occurrence and at appropriate developmental stages of the crop.
| Product name | Technical content | Dosage |
| Krilaxyl Powder | Metalaxyl 35% WS | Seed treatment: 6 – 7 gm/kg seed |
| Amistar Top Fungicide | Azoxystrobin 18.2% + Difenoconazole 11.4% SC | 1 ml/lit of water |
| Cabrio Top Fungicide | Metiram 55% + Pyraclostrobin 5% WG | 3 – 3.5 gm/lit of water |
| Roko Fungicide | Thiophanate Methyl 70% WP | Foliar: 0.5 gm/lit of water or
Drench: 2 – 4 gm/lit of water |
| Splash Fungicide | Chlorothalonil 75% WP | 2 gm/lit of water |
| Kocide Fungicide | Copper Hydroxide 53.8% DF | 2 gm/lit of water |
| Tata Master Fungicide | Metalaxyl 8% + Mancozeb 64% WP | 1.5 – 2.5 gm/lit of water |
| Custodia Fungicide | Azoxystrobin 11% + Tebuconazole 18.3% w/w SC | 1.5 ml/lit of water |
| Curzate Fungicide | Cymoxanil 8% + Mancozeb 64% WP | 2 – 2.5 gm/lit of water |
Learn more about Gummy Stem Blight in Watermelon. CLICK HERE
