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Diseases of Gram.pptx..............................................................................
- 1. Mahatma Phule KrishiVidyapeeth, Rahuri (M.S.), India Affiliated to Saikrupa College of Agriculture, Ghargaon Course Title:- Diseases of Filed and Horticultural Crops and their management-II Course No:- PATH-365 Semester- VI Credit:- 3 (2+1) Course Teacher:-
- 2. Diseases of Gram 1.Ascochyta blight - Ascochyta rabiei 2. Wilt - Fusarium oxysporum f.sp. Ciceris 3. Collar rot - Sclerotium rolfsii 4. Botrytis gray mold- Botrytis cineria
- 3. Ascochyta blight- Ascochytarabiei Etiology- Pathogen- The fungus produces hyaline to brown and septate mycelium. Pycnidia are spherical to sub-globose with a prominent Ostiole. Pycnidiospores are hyaline, oval to oblong, straight or slightly curved and single celled, occasionally bicelled. Favourable conditions • High rainfall during flowering. • Temperature of 20-25˚C. • Relative humidity of 60%.
- 4. Disease cycle- The fungussurvives in the infected plant debris as pycnidia. The pathogen is also externally and internally seed- borne. The primary spread is from seed-borne pycnidia and plant debris in the soil. The secondary spreads is mainly through air-borne pycnidiopores (conidia). Rain splash also helps in the spread of the disease.
- 5. • Symptoms- All aboveground parts of the plant are infected. On leaf, the lesions are round or elongated, bearing irregularly depressed brown spot and surrounded by a brownish red margin. Similar spots may appear on the stem and pods. The spots on the stem and pods have pycnidia arranged in concentric circles as minute block dots. When the lesions girdle the stem, the portion above the point of attack rapidly dies. If the main stem is girdles at the collar region, the whole plant dies.
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- 7. • Management • Removeand destroy the infected plant debris in the field. • Treat the seeds with Thiram 2 g or Carbendazim 2 g or Thiram + Carbendazim (1:1 ratio) at 2 g/kg. • Exposure of seed at 40-50˚C reduced the survival of A. rabiei by about 40-70 per cent. • Spray with Carbendazim at 500 g/ha or Chlorothalonil 1kg/ha. • Follow crop rotation with cereals.
- 8. Wilt of Gram •C.O- Fusarium oxysporum f.sp. Ciceris • Etiology- • Pathogen- • The fungus produces hyaline to light brown, septate and profusely branched hyphae. • Microconidia are oval to cylindrical, hyaline, single celled, normally arise on short conidiophores. • Macroconidia which borne on branched conidiophores, are thin walled, 3 to 5septate, fusoid and pointed at both ends. • Chlamydospores are roughwalled or smooth, terminal or intercalary, may be formed singly or in chains.
- 9. • Favourable conditions •• High soil temperature (above 25˚C). • • High soil moisture. • Disease cycle • The disease is seed and soil borne. • The primary infection is through chlamydospores in soil, which remain viable upto next crop season. • The secondary spread is through irrigation water, cultural operations and implements.
- 10. • Symptoms- • Thedisease occurs at two stages of crop growth, seedling stage and flowering stage stage. • The main symptoms on seedlings are yellowing and drying of leaves, drooping of petioles and rachis, withering of plants. • In the case of adult plants drooping of leaves is observed initially in upper part of plant, and soon observed in entire plant. • Vascular browning is conspicuously seen on the stem and root portion
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- 12. • Management Treat theseeds with Carbendazim or Thiram at 2 g/kg or Carbendazim 1 g+Thiram 1g/kg or treat the seeds with Trichoderma viride at 4 g/kg Pseudonomas fluorescens @ 10g/kg (106 cfu/g) of seed. Apply heavy doses of organic manure or green manure. Grow resistant cultures like ICCC 42, H82-2, Avrodhi, Alok Samrat, Pusa-212, JG- 322, GPF-2, Haryanachana-1 and Kabuli chickpea like Pusa-1073 and Pusa-2024.
- 13. Collar rot -Sclerotium rolfsii • Etiology- • Favorable conditions • High soil moisture, low soil pH and high temperature. • The presence of undecomposed organic matter on the soil surface and high moisture at the time of sowing and at the seedling stage. • Disease incidence is higher when sown after rice or early sown crop.
- 14. • Symptoms • Itcomes in the early stages i.e up to six weeks from sowing. • Drying plants whose foliage turns slightly yellow before death, scattered in the field is an indication of the disease. • Seedlings become chlorotic. • The joint of stem and root turns soft slightly contracts and begins to decay. • Infected parts turn brown white. • Black dots, like mustard in shape known as sclerotia are seen appearing on the white infected plant parts.
- 16. • Management • Deeppluoghing in summer. • Avoid high moisture at the sowing time. • Seedlings should be protected from excessive moisture. • Destroy the crop residues of last crop and weeds before sowing and after harvest. • All undecomposed matter should be removed from the field before land preparation. • Treat the seeds with a mixture of Carbendazim + Thiram (1:1) @ 2g per kg of seed.
- 17. Botrytis gray mold:Botrytis cineria • Symptom • Lack of pod setting is the first indication. • Under favourable conditions, foliage shows symptoms and plants often die in patches. • Shedding of flowers and leaves, covered with spore mass can be seen. • Lesions on stem are 10-30 mm long and girdle the stem fully.
- 18. • Tender branchesbreak off at the point where the gray mold has caused rotting. • Affected flowers turn in to a rotting mass. • Lesions on the pod are water-soaked and irregular. • On infected plants, the pods contain either small, shriveled seeds or no seeds at all.
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- 20. • Management • Avoidexcessive vegetative growth. • Intercrop with linseed. • Avoid excessive irrigation. Use compact varieties. • Deep summer ploughing Reduce plant density and increase in air passage between the plants. • Seed treatment with Carbendazim + Thiram (1:1) @ 3g/kg of seed is recommended or Spray the crop with Captan 5 - 6 kg/ha at 15 days interval./Spray of Carbendazim @ 1.5g/lit of water is recommended./Spray Mancozeb @3 g/lit of water.