Bendangsenla, E Lireni Kikon and Kavi Sumi
Toria (rapeseed) is an oilseed crop that is grown for its oil-rich seeds. In Nagaland, Toria is considered to be a profitable rabi oilseed crop. However, like any other crop, toria is also susceptible to fungal diseases that cause significant crop losses. Therefore, it is essential to control fungal diseases in toria crop to ensure good yields and quality seeds.
Before discussing the management practices, it is important to identify the fungal diseases that affects the crop. Some of the common fungal diseases in toria are listed below:
1. Alternaria blight (Alternaria brassicae & A. brassicicola): Alternaria blight is a major fungal disease that affects the leaves, stems, and pods of toria plants. It causes small, circular, brown to black lesions on the infected plant parts, eventually leading to premature defoliation and reduced seed yield.
2. White rust (Albugo candida): Characterized by white, creamy, blister-like pustules on the lower leaf surface, often appearing alongside downy mildew (a complex infection), leading to stunted growth.
3. Sclerotinia Stem Rot (Sclerotinia sclerotiorum): A soil-borne disease causing cottony white mycelial growth and rotting on stems. Symptoms include premature ripening and shredding of stems, plant wilting, and desiccation. It is particularly severe when cool, humid weather occurs, often in densely planted, early-sown crops.
4. Powdery Mildew (Erysiphe cruciferarum): Appears as white, powdery patches on leaves, stems, and pods, reducing photosynthetic capacity. In later stages, the leaves may turn yellow, then brown, and fall off prematurely.
Some of the effective ways for managing Toria crop is mentioned below:
1. Use resistant varieties: It is the most effective way to control fungal diseases in toira crop. Select varieties that have maximum degree of resistance to the fungal disease that is prevalent in Nagaland. Use healthy and certified quality seeds.
2. Crop rotation: This method is another effective way to manage fungal diseases in toria crop. Crop rotation with non-host crop like cereals, legumes should be done to prevent the build-up of fungal pathogens in the soil.
3. Seed treatment: Seed treatment using fungicides before sowing is a useful and economical way to prevent seed-borne fungal diseases.
4. Cultural practices: Cultural practices like proper spacing, timely weeding and good drainage can assist in managing fungal diseases in toria crop. It will help in reducing humidity and moisture levels, which are favorable for the growth and development of fungal pathogens.
5. Avoid excessive use of Nitrogen fertilizers.
6. Destroy crop residues to prevent pathogen survival, e.g., Sclerotinia Stem Rot (Sclerotinia sclerotiorum).
7. Spray 3-4 times at 10-15 days interval with mancozeb (Dithane M45) @ 0.2% for Alternaria leaf blight and white rust diseases.
8. To manage Sclerotinia rot, apply Trichoderma-colonized cow dung or vermicompost into the soil, followed by seed treatment with garlic bulb extract (2%) and Trichoderma (10g/kg seed).
9. For Powdery mildew management, spray 2-3 times at 10-15 days interval with sulphur dust at 30kg/ha or by spraying 2g wettable sulphur or 1 ml dinocap or 1 ml tridemorph per litre of water
Conclusions: One of the major threats to toria crop is fungal diseases that causes considerable losses and also deteriorates the quality of yield produced. Therefore, it is important to implement appropriate management practices to prevent and control the fungal diseases of toria. The measures discussed above are effective and can be used individually or in combination. However, integrating all the management practices will produce the best result in managing the fungal diseases of toria.
Bendangsenla, Department of Plant Pathology, School of Agricultural Sciences, Medziphema Campus, Nagaland University- 797106
E Lireni Kikon Krishi Vigyan Kendra (KVK), ICAR, Dimapur Centre
Kavi Sumi, ICAR- AICRP on Kharif Pulses, SAS:NU
