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Studies On Colletotrichum Blight Of Bitter-Gourd
(Birsa Agricultural University, Ranchi, 2001) Savita Ekka; S.C.Dubey
Bitter gourd (Momordica charantia Linn.) is an important annual cucurbitaceous vegetable growing widely in Jharkhand as well as in India. The crop was severely affected by a defoliating disease Colletotrichum blight caused by Colletotrichum capsici (Syd.) Butler and Bisby. Intensity of disease varied from 37.4 to 74.9 per cent in different locations of Ranchi. The characteristic blight symptom of the disease was observed on leaves and fruits. The pathogen was isolated, purified and proved pathogenic following standard techniques. Among the varieties/lines of bitter gourd screened against the disease, none of them was found to be resistant. Only one variety i.e. Creeper showed moderately resistant reaction against disease. All ten plant species belonging to five families were infected during host range studies. Disease appeared during second week of September in field and increased gradually upto maturity of the crop. Apparent infection rate was maximum on 10th October in the presence of 20.5-29.1°C and 19.9-29.6°C temperature, 69.0 88.5 per cent and 62.5-91.3 per cent relative humidity, 0.3-9.5 mm mean rainfall and 2-4 numbers of rainy days. Significant negative correlations were established between minimum temperature, maximum and minimum relative humidity, mean rainfall, rainy days and disease development. Stepwise multiple regression analysis clearly indicated that minimum relative humidity and numbers of rainy days significantly negatively contributing in the prediction of disease development and accounted for more than 89 and 84 per cent variation, respectively. Vitavax, Tilt and Thiram inhibited cent per cent growth of the pathogen in vitro. Rest fungicides in order of superiority were Topsin-M, Kitazin, Bavistin, Captaf, Benlate, Contaf, Indofil M-45, Blitox-50, Kavach and Ridomil. Vitavax (2g kg seed) and Topsin-M (2g kg seed) treated seeds gave maximum germination and elimination of seed borne infection, respectively. Under field condition, integration of seed treatment with Vitavax and spraying of Tilt (0.1%) managed the disease efficiently with minimum disease intensity and highest fruit yield. Seed treatment with Vitavax and spraying of Topsin-M (0.05%) was next effective treatment with highest per rupee return..
Open Access
Studies on Web blight of Winged Bean
(Birsa Agricultural University, Ranchi, 2001) Mithilesh Kumar; K. K. Rai
Winged bean (Psophocarpous tetragonolobus V.A.Parthasarathy) suffers from a very devastating disease web blight caused by Thanatephorus cucumeris (Frank.) Donk = Rhizoctonia solani Kühn which has been found to be limiting factor in production of winged bean in the Jharkhand. Typical web blight symptoms were observed on all the infected aerial parts of the plants. The pathogen was isolated, purified, identified and proved pathogenic. Disease was initiated from second week of September in field with maximum apparent infection rate and gradually increased. Significantly negative correlation was established in between weather factors and disease intensity during both years of experimentations. Multiple regression analysis equations showed that minimum temperature significantly (negative) contributing in the prediction of disease development and accounted for more than 80% variations. Only one cultivar namely EC-38955 showed moderately resistant reaction against pathogen in the field under artificially inoculated conditions. Vitavax, Bavistin, Blitox-50, Contaf, Tilt, Captaf and SAAF were found most effective fungicides as they completely inhibited the growth of the pathogen in vitro. The integration of fungicides and Gliocladium virens (Trichoderma virens) provided good protection to germinating seeds than the any one alone in laboratory condition. Seeds treated with G.virens (10° spores/ml/10g seed) + Vitavax (1 g kg) gave significantly maximum inhibition zone/area covered by antagonist around seed. treatment enhanced seed germination under field conditions. Soil application of G.virens multiplied on pulse bran-saw dust-tap water (3:1:4 w/w/v) along with seed treatment with G.virens + Vitavax provided highest seed germination. Seed treatment with G.virens + Vitavax along with spraying of Tilt gave minimum disease intensity and highest pod yield followed by seed treatment with spraying of Contaf.
Open Access
Studies on Major Fungal Diseases of Soybean Occurring in Chotanagpur Region of Bihar
(Birsa Agricultural University, Ranchi, 2001) Basanti Oraon; K.K. Rai
Soybean (Glycine max (L) Merril) in an important oil seed crop belongs to the family Leguminosae. It is cultivated through out the world chiefly for oil seed and pulses, Is highly nutritious, and contains high percentage of proteins, carbohydrates and vitamins. It has originated from China and was introduced in Madhya Pradesh during the year 1882. At present, the crop has occupied fifth position on world map of soybean. It is being grown in 4.2 milion hactare with a production of about 7,300 Lakh tons in India The crop is vulnerable to a number of diseases. Amongst these, Alternaria leaf blight caused by A. tenuissima, (Kunze Ex Pers.) wiltshire, Pod blight caused by C. glycines Hori and Rhizoctonia aerial blight caused by R. solani Kuehn are most destructive diseases of Soybean in the Chotanagpur region of Bihar. The crop was found to be severely affected by the above Pathogens which caused considerable losses in the production of Soybean in Chotanagpur Plateau of Bihar. The intensities of diseases ranged from 14.33 to 40.33 per cent in different localities in and around Ranchi. The characteristic symptom of the diseases caused by A. tenuissima, C. Glycines and R. solani were observed on leaves, petioles, stems and pods. The Pathogens were isolated, purified, and Koch's postulate tests were satisfied. Potato dextrose agar was found to be the best medium for growth and sporulation of A. tenuissima, and also growth and sclerotia formation in R. solani whereas Richards' agar supported the best growth and sporulation of C. Glycins. Amongst liquid media, Richards' medium was best for the growth and sporulation and sclerotia formation of A. tenuissima, and R. solani, respectively. However, C. Glycines gave best growth & sporulation on Potato dextrose broth also. pH 6.5 and temperature 25° C were found to be best for growth and sporulation/ sclerotia formation of all the Pathogens. Sucrose and Potassium nitrate were found to be the best sources of carbon and nitrogen, respectively for A. tenuissima, sucrose and calcium nitrate for C. glycines and maltose and potassium nitrate for R. solani. Maximum growth of all the three Pathogens was noted in Alternate light and darkness followed by continuous darkness and light. Seventyfive, ninety and thirty days old plants were highly susceptible to Allternaria leaf blight, pod blight and Rizoctonia blight, respectively. Alternaria leaf blight development was maximum during September with an average temperature of 22.5°C, R.H. 86 per cent, Total Rainfall 11.0mm. and maximum Pod blight development concided with an average temperature of 23.5°C, R.H. 71.5 per cent and Total Rainfall 4.9mm, during the month of October, whereas maximum Rizoctonia aerial blight disease development was in the month of August with an average temperature of 27.0°C, R.H. 86.1 per cent and total Rainfall 26.4mm. Amongst cultivars of Soybean screened only six varitivers viz., Birsa Soybean, JS-80-21, Bragg, NRC-32, DS-93-40-8, and MAUS-41 were found to be moderately resistant against all the three diseases evaluated. However, complete. resistance could not be shown by any one. and Fluchloralin was found to be best weedicide in suppressing the diseases of Soybean followed by oxyflourfen, Metachlor and Alachlor in suppressing the disease under studies. In management of diseases, Indofil M-45 (0.25 per cent) was found to be the best fungicide against Alternaria blight and Bavistin (0.05 per cent) for Pod blight and Bavistin (0.05 per cent) and Indofil M-45 (0.25 per cent) for Rhizoctonia aerial blight. These fungicides may be utilized by the farmers of the region for the control of respective diseases.
Open Access
Helminthosporiosis of Wheat in Chotanagpur Plateau of Bihar And its Management
(Birsa Agricultural University, Ranchi, 2000) Arvind Kumar; D. K. Jha
Wheat (Triticum aestivm L.) is most widely cultivated grain crop of the world, both in regrad to antiquity and its use as a source of human food. In India, wheat is grown over 24 million hectares, which yield nearly 63.02 metric tonnes of grain. In Bihar, it is cultivated in 1.84 million hectares with total production of 2.86 metric tonnes and average productivity of 15.56 quintal per hectare. In plateau region of Bihar, it occupies an area of 50.09 thousand hectares with an average production of 51.08 thousand tonnes which figures in productivity of about 10.20 q/ha. It is an important source of food for human consumption, feed for livestock and wheat starch for industrial purposes. Wheat is vulnerable to a variety of diseases. Helminthosporiosis of wheat caused by Helminthosporium sativum P.K. & B. and Helminthosporium tritici-repentis Died is one of the most destructive diseases of wheat. This disease is very common and invariably prevalent in the Chotanagpur plateau region of Bihar. During survey, wheat crop was found to be severely infected with the Helminthosporiosis causing considerable losses in production of wheat The disease intensity ranged from 35.0 to 61.5 per cent in different localities of Ranchi. The two species causing the Helminthosporiosis of wheat, viz., H. sativum and H. tritici-repentis are quite different to each other in symptom expression and in morphological characters. H. sativum produced straw coloured spots with dark brown margin but H. tritici-repentis formed light. brown coloured spots with yellow halo margin. The former had fusoid conidia (widest in the middle) with heavy wall and rounded ends and brown to olivaceous colouration while the later produced fusiform elliptical conidia, hyaline in colour with snaky head at the basal cell. The characteristic symptom of the disease was observed almost on leaves. The pathogen was isolated, purified by standard method and satisfied Koch's postulate tests. All seven graminaceous hosts were infected by both the pathogens during host range studies. The conidia of both the pathogens remained viable in culture throughout the year under laboratory condition but their viability decreased with the increase in the period of storage. The pathogens also survived through plant debris and infected seeds, stored under laboratory condition throughout the year while it lost the viability in the soil after two months. The pathogens remained pathogenic throughout the survival period. Seeds of wheat variety "Sonalika" showed 15 and 8 per cent seed infection with H. sativum and H. tritici-repentis, respectively. Wheat crop sown between 7-21 November in both the years of experimentation, influenced less disease development and better yield. Late sowing increased the disease development in nature. Application of 100 kg N/ha with recommended doses of P and K. i.e.. 50 and 25 kg/ha, respectively, under irrigated condition and 40 kg. N/ha with recommended dose of P. i.e. 20 kg/ha, under un-irrigated condition helped in the reduction of Helminthosporiosis and increased the grain yield. The intensity of the disease increased gradually in field as the plant age increased. Maximum disease development was favoured by the temperature 22.2 to 27.3°C, relative humidity 16.1 to 64.0 per cent and absence of rain, at maturity of crop plants. In general, temperature was significantly positively and relative humidity significantly negatively correlated with the disease development in nature. Leaves extract of Lawsonia inermis (Henna/Menhadi) inhibited. maximum radial growth of both the pathogens. Five sprays of crude extract (10 per cent) of Lawsonia inermis, at an interval of 15 days gave satisfactory control of the disease. Control of the disease by the crude extract of L inermis was a new attempt initiated here, which oduced good result and a new finding. Only three cultivars, namely, H.P. 1761 (Jagdish), HP 1731 (Rajlakshmi) and HUW 206 showed resistant reactions against both the pathogens, under artificial epiphytotic conditions. Thiram inhibited cent per cent growth of the pathogen followed by Topsin-M in vitro. Rest fungicides in order of superiority were Indofil, M-45, Kavach and Bavistin. Thiram (0.2%) followed by Bavistin (0.2%) was the most effective seed dressing fungicide in minimising the disease intensity and increasing the yield. Seed treatment with a @2 g per kg seed with integration of three sprays of Topsin-M (0.1%) proved to be the most effective treatment in which the least disease intensity and highest yield were recorded, under field conditions. Indofil M-45 and Kavach ranked second and third in the evaluation.
Open Access
Studies on Alternaria Spp.Causing Leaf Blight in Cauliflower and Its Management in Chotanagpur Region
(Birsa Agricultural University, Ranchi, 1999) Navin Kumar; K.K.Rai
Leaf blight disease of cauliflower (Brassica oleracea var, botrytis L.) caused by Alternaria brassicae is a widespread disease in Bihar. Spots were small, circular measuring 2-5 mm which gradually enlarged upto 10-25 mm in diameter. These spots were lighter in colour but later on changed to dark brown. Conspicuous zonations or concentric rings were formed on almost all the fully developed spots. Alternaria brassicae: Conidia obclavate, muriform, bottle shaped, attenuated into a long conspicuous beak at the tip and slightly narrowed at the base. Conidiophores - simple, erect or ascending straight, sometimes flexuous, more or less cylindrical. Mycelium-short, compact, septate, branched, hyaline at first, later on turned light brown to olivaceous gray, inter and intracellular, 4.8 μ wide and 3.6 u in diameter. Alternaria brassicicola Conidia variable in shape, cylindrical to oblong, poorly developed beak, muriform, light olivaceous to dark olivaceous, in long chain of 6 to 8 spores Mycelium - short, compact, septate, branched, sometimes hyaline, olive gray to grayish black, inter and intracellular 4.2 µ in diameter. Conidiophore simple, erect or ascending straight, cylindrical, olivaceous, septate, 5-7.5 x 35-45 μ, conidia born terminally on conidiophore. Radial growth and biomass production was found significantly superior in Richards and potato dextrose compared to other media followed by leaf extract, Czapek's agar and glucose asparagine. Optimum temperature and pH for growth and sporulation of the fungus were found 25°C and 5.5, respectively. Sucrose 1% proved to be the best medium for germination whereas distilled water and rain water resulted the least percentage of germination of spores. The fungus produced significantly maximum amount of 423.3 mg dry mycelial mat and sporulation in the standard Richard's medium containing sucrose and followed by glucose, mannitol and maltose. Organic form of nitrogen as Urea and asparagine was found to be the best source of nitrogen as compared to inorganic source. Among the inorganic source the fungus had much more affinity with nitrate form of nitrogen as sodium nitrate and ammonium nitrate than ammoniacal form ie. Ammonium chloride. Thiamine was found to be the best vitamin for maximum mycelial mat production and sporulation. Bavistin was found most efficacious at 200 ppm whereas 'karanj and neem oil completely inhibited the growth at 10,000 ppm. In field condition also this fungicide was found significantly superior at 0.05% concentration. Spore germination of the fungus was completely suppressed at 75 ppm. KT 9, Pusa subhra, Improved Japanese, Pusa Katki, Aghani and Poosi varieties: of cauliflower were found moderately resistant to Alternaria leaf blight disease.
Open Access
Management of Major Diseases of Brinjal In Chotanagpur
(Birsa Agricultural University, Ranchi, 1999) Sajjad Hussain; U.Choudhary
Brinjal or egg plant (Solanum melongena L.) is one of the most important vegetable crop cultivated in Chotanagpur region extensively throughout the year and is attacked by a number of pathogens, amongst which predominant appears to be bacterial wilt and fungal leaf spot. In view of increasing importrance of bacterial wilt of brinjal caused by Ralstonia (Pseudomonas) solanacearum Smith and leaf spot caused by Alternaria alternata in Chotanagpur region, the management aspects of these diseases were proposed. Wilt intensities in different localities of Chotanagpur region varied between 10.0 to 64.8 per cent whereas leaf spot intensities in different localities varied between 5.2 to 17.6 per cent. The first sign of wilt disease appears as the loss in turgidity of leaves, withering and then drying of top leaves followed by lower leaves. In advance stages the entire plants are wilted. The leaf spot sign on leaves first appeared at the tip margins small light brown necrotic spot of pin head size. These spots gradually enlarged in size and other remained circular or assumed irregular shape became dark brown to grey in colour and defoliation of leaves also occured. The spots are first appeared on the lower leaves on later spreading upwards. Morphological studies confirmed that the bacterium was short, rod shaped motile, non-capsulated and gram negative whereas the fungal was with black, long acropetal chains conidia, septate dark mycellium, conidiophores single or in group with septation." In cultural studies, Tetrazolium chloride proved to be the best for excellent growth of the bacterium pathogen whereas for fungus the best media was Potato dextrose agar. Wilt incidence was favoured by high temperatures accompanied by high relative humidity during the crop period. In nature incidence of leaf spot disease increased gradually is the age of plants increased. Amongst the 15 varieties tested against the both pathogen (Bacteria and Fungus) only 3 varieties namely SM 6. KT 4, Punjab barasati were found to be resistant to wilt and leaf spot.
Open Access
Studies for Variability in Alternaria Triticina on Wheat in Bihar
(Birsa Agricultural University, Ranchi, 1999) Ashok Kumar; D. K. Jha
Wheat (T. aestivum L.) is the most widely cultivated crop of the world. Among the wheat growing countries India ranks fourth in terms of productions (63.02 MT) and area (24 M ha) under cultivation with 26 q/ha average yield. In Bihar, it is cultivated in 1.84 M ha with total production of 2.86 MT and average productivity is 15.56 q/ha. It is an important source of food for human consumption, feed for livestock and wheat starch for industrial importance. Wheat crop suffers from many fungal, bacterial and viral diseases which reduce the yield. The leaf blight disease of wheat caused by Alternaria triticina Prasada and Prabhu, is one of the most destructive diseases causing considerable losses in production of wheat in most of the wheat producing areas of India including Bihar and thus neutralizes the costly inputs of the cultivation for higher productivity. In view of its significance, investigations on leaf blight disease of wheat were conducted to find out the variability of the pathogen along with some basic investigations of the disease especially to develop suitable management strategies. The three isolations of the pathogen were made and designated as A-1 (Ranchi isolate), A-2 (Pusa isolate) and A-3 (Sabour isolate) on the basis of morphological and pathogenic behaviour. The conidia of isolate A-1 were slightly bigger in size (mean 28.9 x 9.8 μm), than the isolate A-2 (mean 26.3 x 6μm) and A-3 (mean 25.8 x 9.5μm). The morphological characters of three isolates on different culture media have been described in detail. While proving the Koch's postulates, a considerable variability in pathogenicity among the isolates were observed. The isolate A-1 was highly virulent as it required less time for infection and produced more number of lesions of bigger size. The isolates also varied in their nutritional requirement in orderto grow and sporulate on different liquid and solid culture media. Potato dextrose agar medium supported maximum growth of all the isolates with significantly superior (mean 68.7mm) performance of isolate A-1. pH 6.0 was found to be optimum for the growth and sporulation of all the isolates and isolate A-1 had significantly superior growth at various pH levels. evaluated followed by isolate A-2 and A-3 which were at par.. Spore germination of all the isolates did not differ significantly with each other at various levels of humidity tried and cent percent RH induced highest spore germination for all the isolates. Isolate A-1 had maximum growth under all the three condition i.e., continuous light, alternate light and continuous darkness over the isolate A-2 and A-3. Photo inhibitory effect on sporulation was evident in all the three isolates of A.triticine. None of the plant other than wheat found susceptible during host range study and their were no variability observed among the isolates of the pathogen regarding their host range. Fath And The intensity of Alternaria leaf blight increased with increase in the level of nitrogen applications. Phosphorus or Potassium had no significant impact on the disease intensity separately, but reduction in disease development was observed when they were supplemented with the higher dose of nitrogen (250kg/ha). Out of fifty eight wheat cultivars screened only twelve cultivars viz., BAU 33, BAU 2398, BAU 2378, BAU 2395, BAU 2375, HP 1209, KS 26, MACS 9, M 8223, N 59, NI 5439 and PAN 3043 were found resistant to blight disease. Indofil M-45 (0.2%) was found to be best in vitro against the pathogen and reduced the disease intensity and increased the yield in field condition followed by Dithane Z-78 (0.2%).
Open Access
Management of Ringspot Virus Disease of Papaya in Chotanagpur
(Birsa Agricultural University, Ranchi, 1998) Narendra Kudada; Dr. S. M. Prasad
Open Access
Investigations on Epidemiology And Management of Leaf Blight Disease of Ragi
(Birsa Agricultural University, Ranchi, 1998) Rajiv Kumar; D. K. Jha
Ragi blight, etiologically associated with the fungal pathogen (Helminthosporium nodulosum Berk, and Curt.) is the most rigorous ailment in Chotanagpur plateau region of Bihar. In view of its increasing importance, studies on this disease emphasizing on epidemiology and management were carried out. The morphological characters of H. nodulosum were studied both from nature as well as culture and has been described in detail. Pathogenicity was conférmed as per Koch's postulate tests. Maximum perpetuational period of the pathogen was recorded to be ten months in infested fingers at 2.5 cm soil depth. And, it was observed to perennate on a number of weed hosts growing in and around ragi field. Of these, wild Eleusine, Setaria and Panicum were found to be the most important weed host. The maximum seed infection (H. nodulosum) of 44.00 per cent with minimum seed germination of 52.00 per cent were recorded in cv. BM-1. The most susceptible age of the ragi plants against pathogen was found to be 64 days with respect to disease development The maximum disease development coincided with temperature (20.60 and 21.65°C), relative humidity (77.60 and 78.75 per cent), total rainfall (26.97 and 14.80 mm) and sunshine (3.48 and 7.20 hours) during the month of August. Least leaf infection was recorded on 29th June sown VR-550 variety, whereas, 1 August sown VR-550 variety showed least neck and finger infection. The optimum levels of N, P and K with respect to disease suppression and maximum grain yield were observed to be 50:80:50 kg h-1, respectively. A-404 showed the least disease incidence of 12.766 per cent supplemented with no nitrogen, whereas, 80 kg N h-1 yielded maximum grain yield. The minimum disease incidence and maximum grain yield was recorded on 20 days seedling planted at 20x10 cm² spacing. The minimum disease severity (8.10 per cent) and highest intercropped yield (6.10 q b-1) were recorded when ragi was intercropped with arhar with the highest monetary returns over pure crop of Rs. 12,800. The loss in grain yield ranged from 18.680 to 63.153 and straw yield for 14.709 to 35.114 per cent in varieties A-404, BAU-2 and BM-1 due to blight disease. Out of various treatments, five sprays of crude extract (10 per cent) of Impatiens balsamina at an interval of 15 days gave satisfactory control of the disease. Out of 135 entries screened, only ten entries viz., DM-1, GE-1348, GE-2400, GE 2773, GE-2878, GE-2894, GPU-36, IE-2885, IE-2893 and IE-3158 were found resistant to blight disease. The best control was achieved with two sprays, Systhane (0.05 per cent) followed by Blitox (0.20 per cent) with maximum turn over of Rs. 5.31 from an investment of Rs. 1.00 during fungicidal control of the blight disease of ragi.

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