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Open Access
Epidemiology of potato apical leaf curl begomovirus disease in potato
(CCSHAU, 2005) Mandal, Ram Baboo; Dhawan, Poonam
The present investigations on epidemiology of potato apical leaf curl begomovirus diseases in potato were undertaken during 2003-04. PALCV infected plants exhibited symptoms such as vein clearing, vein thickening, crinkling, apical leaf curling, waviness of leaf margin, leaf smalling, leaf distortion and stunting of plant. There was some variation in the expression of symptoms in four different cultivars. Per cent incidence and severity of the disease varied from cultivar to cultivar and also in the same cultivar grown at different locations. Per cent disease incidence was found to range between 10.30 to 34.53 in Haryana depending upon cultivars and the locations. Cultivar Kufri Chipsona showed least incidence and mild severity of the disease. Higher per cent disease incidence with very severe symptoms was observed in cv. K. Sutlej. Higher severity category and more per cent disease incidence was noticed in crop raised from farmer’s seed in comparison to breeder’s seed of the same cultivar. Reduction in yield per hectare in crop raised from farmer’s seed over breeder’s seed ranged from 8.79% to 18.40% in different cultivars of potato. There was significant reduction in growth and yield parameters of diseased pants over healthy ones in all the four cultivars of potato. Reduction in yield of diseased plants ranged from 30.17% to 42.58%. It was lowest in cv. K. Bahar and highest in cv. K. Sutlej. In polymerase chain reaction (PCR) diagnosis, a product of expected size of approximately 2.7 kb was detected by gel electrophoresis which suggests presence of geminivirus in infected plants. PALCV was transmissible through whitefly and grafting but not by mechanical inoculation of sap. A single whitefly was able to transmit the virus but fifteen whiteflies per plant were required to obtain highest per cent transmission of 88.88%. Minimum acquisition and inoculation access feeding periods were 30 min each. The host range of PALCV was confined to five families viz. Asteraceae, Caricaceae, Euphorbiaceae, Malvaceae and Solanaceae. Weather variables viz. maximum temperature of 22±2ºC and morning relative humidity of about 90 per cent were found favourable for whitefly population build up and disease incidence. Per cent disease incidence had significant and positive correlation with whitefly population and morning humidity but negative with maximum temperature. Multiple regression equation developed by using whitefly population and weather variables could predict the disease incidence from 87 to 93% in different cultivars of potato.
Open Access
Evaluation of different strains of temperature tolerant button mushroom (Agaricus bitorquis)
(CCSHAU, 2005) Yogesh Kumar; Pahil, V.S.
The present studies concluded that five different strains tested for yield and other agronomic characters showed that NCB-14 produced highest yield (15.79kg) whereas NCB-15 produced heaviest fruit bodies and NCB-13 produced maximum number of fruit bodies (1151.83) being the lightest average weight of fruit bodies. Among media PDA, pH level of 7.0 and temperature of 30 1C supported best mycelial growth. Studies on two methods of composting revealed that short method of composting out yielded the long method of composting. Among the various spawning method tried, thorough spawning proved best. Similarly the results of different depth of compost showed that 25 cm depth of compost produced highest yield (15.12kg) of mushroom. Studies on various casing material showed that BRH+FYM (1:1) w/w produced maximum number of fruit bodies. Among the different level of casing thickness, 3.75 cm thickness produced best yield.
Open Access
Studies on the efficacy of plant extracts against bacterial blight pathogen (Xanthomonas axonopodis pv. cyamopsidis) of clusterbean (Cyamopsis tetragomnoloba (L.) Taub)
(CCSHAU, 2005) Kamalpreet Kaur; Jalali, Indu
Bacterial blight caused by Xantomonas axonopodis pv. cyamopsidis is one of the most destructive disease of clusterbean. Considering the deleterious effect of these chemicals on life supporting systems, there is an urgent need for alternative or integrated methods for effective management of pathogenic microorganisms without adversely affecting the environment. Present study was initiated to develop an environmentally safe non-hazardous strategy for the management of this disease. Bacterial blight pathogen was isolated from disease tissue of clusterbean plants occurring in the region and the Koch postulates were proved. Aqueous and methanolic extracts of twelve plants viz; leaves of Emblica officinalis, Cassia fistula, Tagetis sp.,Withania somnifera, Rauvolfia serpentia, Glycyrrhiza glabra, Andrographis paniculata, Eucalyptus citriodora, Catharanthus roseus, cloves of Allium sativum and leaves and kernels of Syzium cumini were assayed in vitro for their antibacterial activity by paper disc method. Out of them filter sterilized aqueous leaf extract of aonla (Embilica officinalis) exhibited maximum inhibition zone of the X. axonopodis pv. cyamopsidis followed by eucalyptus ( Eucalyptus citriodora) and marigold (Tagetis sp.) leaf extract which was comparable with 10μg, 5μg and 1.25μg of streptocycline/disc. However, none of the methanolic plant extracts tested exhibited antibacterial activity against the test pathogen. Evaluation of minimum inhibitory concentration of aonla and eucalyptus aqueous leaf extract revealed that with increase in dilution of extract there was reduction in the antibacterial activity. Maximum bacterial inhibition was recorded with equal dilution of extract and water (1:1 w/v). Thermo stability studies provide clear indications that the aqueous extract of aonla and eucalyptus was thermo labile as they lost their antibacterial activity on heating the extracts to 50o C and beyond. However, there was reduction in antibacterial potential of aonla and eucalyptus leaf extract when kept at 25OC and –4OC temperature for 48 h from that of its fresh extract. Present studies indicate that storage of aonla and eucalyptus leaf extract at room temperature for 15 and 30 days completely destroyed the antibacterial activity. However, storage at 10OC for 15 and 30 days exhibited reduction in their antibacterial potential. Deep freezing for 1 and 6 months further reduced the antibacterial activity of aonla leaf extract, where as, in eucalyptus leaf extract there was complete loss of antibacterial activity under similar conditions, thus suggesting these the two phyto-extracts possessed poor shelf life and were best when used fresh. Aqueous leaf extract of aonla and eucalyptus were also found to be bactericidal to the test pathogen in broth culture as well as on poisoned plates. All the botanicals used as spray reduced the bacterial blight of clusterbean. However, aonla leaf extract (1:10) provided maximum disease control followed by eucalyptus and marigold leaf extract spray after challenge inoculation with the pathogen Xanthonumas axonopodis pv. cyamopsidis and were at par with streptocycline in reducing the bacterial blight of clusterbean after 80 days of sowing.
Open Access
Studies on the management of black scurf of potato caused by rhizoctonia solani kuhn.
(CCSHAU, 2005) Pardeep Kumar; Gandhi, S.K.
The fungus Rhizoctonia solani Kuhn causing black scurf of potato was isolated and purified. Among seven bioagents evaluated in vitro against R. solani by dual culture method fungal bioagents viz., Trichoderma viride, T. harzianum and G. virens showed their maximum potential at lower pH (5 and 6) while bacterial bioagents viz., Pseudomonas fluorescens, P. maltophila, Bacillus subtilis and Azotobacter chroococcum were more active in the alkaline range. However, T. viride was effective in wide pH range. Similarly when bioagents were tested at different temperature regimes P. maltophila and T. viride showed their potential over a wide temperature range while others were effective in the temperature range of 20-30 oC. On the basis of antagonistic potential of bioagents in vitro five bioagents were selected for evaluation in the field both as seed and soil treatment. Best results in terms of reduction of disease severity were obtained in case of P. maltophila and T. viride. Further both the antagonists increased the tuber yield appreciably in comparison to check. Plant height was not affected by these treatments. Tubertreatment done with few resistance inducing chemicals viz., indole acetic acid, indole butyric acid, salicylic acid, nicotinic acid and benzoic acid at 0.125 and 0.25 per cent concentrations revealed salicylic acid to be most effective in reducing the disease followed by nicotinic acid. At 0.125 per cent concentration reduction in plant height was noticed on IAA and IBA at 30 days after sowing which recovered at 60 days after sowing. Effect of these chemicals on tuber yield were not well marked.
Open Access
Strain improvement of oyster mushroom (Pleurotus sajor-caju (Fr.) Singer.) through gamma irradiation
(CCSHAU, 2005) V. Chandra Sekhar; Surjeet Singh
Various methods have been employed in mushrooms for strain improvement. Amongst these, strain development through mutation breeding has been tried on a few mushroom species such as white button mushroom but no systematic work has been done for the strain improvement in oyster mushroom through gamma radiation. In the present study production of better quality strain(s), mutation breeding using gamma irradiation was attempted. Mycelium of Pleurotus sajor-caju was exposed to different doses of gamma rays and studied for various growth characteristics, immediately after exposure and upon sub culturing also. Based on qualitative and quantitative attributes three mutants namely Psm-1, Psm-3 and Psm-6 were selected and used for raising crop in both winter and summer months along with the Parent. After analysis of different characteristics, Psm-6 was found superior than the others as well as Parent. It had whitish grey coloured fruit bodies during both the crop seasons and had higher yield during winter months than Parent, which are desirable attributes and were absent in the Parent as well as other mutants. These mutants were further investigated for cellulase activity and nutritional composition, but their performance was at par with that of the Parent, thereby indicating that gamma radiation had no affect on cellulase activity and nutritional composition of P. sajor-caju. The mutants were also analyzed for genetic variability through isozyme electrophoresis and protein banding pattern and it was found that mutants had distinct banding patterns in comparison with Parent regarding isozyme namely esterase (EST) and malate dehydrogenase (MDH) and protein profile indicating variability has taken place at genetic level because of gamma irradiation.
Open Access
Studies on cumin blight caused by alternaria burnsii (Uppal, Patel and Kamat)
(CCSHAU, 2005) Shyam Sunder; Mehra, Rakesh
The laboratory, screen house and field studies entitled, “Studies on Alternaria blight of cumin caused by Alternaria burnsi (Uppal, Patel and Kamat)” was conducted at Research area of Department of Plant Pathology CCS Haryana Agricultural University, Hisar during winter (rabi) season of 2004-05. The experiments were laid out in randomized block design in field and completely randomized design in lab conditions. Alternaria blight disease of cumin appears in severe form during 2004-05 crop season. Symptoms of the blight disease appears as leaf tip become necrotic, turned purple and ultimately black in colour and infection extends to all the above ground parts viz., stem parts under severe infection, no seed formation, If formed, are non-viable. Conidia with beak 20.0 to 64.5 μ and 12.0 to 20.2 μ or without beak, 3-6 transverse septate, having 6 to 8 spore chain with rounded base. Conidiophores are branched, 2-6 celled and septate. Out of 50 genotypes/varieties of cumin screened against Alternaria blight under field and screen house conditions, none was found highly resistant and resistant. However, five lines, viz., AC-167, UC-342, RZ-209 (2001), UC-198, UC-216 were moderately resistant under both the conditions. Rest of the lines showed susceptible to highly susceptible reaction. Out of four dates of sowing early sown (20th Oct.) and late sown (5th Dec) crop showed less disease severity as compared to 5th Nov. 2004 and 20th Nov. sown crop. Maximum disease severity was in the crop sown on 5th Nov. Among the four varieties highest disease severity was observed in RS-1 variety and least disease severity on variety GC-3 on all the dates of sowing. Both the temperatures, morning (7.5-12.90C) and evening (21-240C) and relative humidity (91-95%) play a major role in the disease development. Regression equations have been developed for 4 varieties. Among the 10 plant extracts evaluated against Alternaria burnsii, datura and garlic plant extracts were found best followed by neem and aak plant extracts. Among four fungal antagonists evaluated in vitro against Alternaria burnsii, Trichoderma viride, T. harzianum were found most effective. Among bacterial antagonists, Pseudomonas fluorescens showed good control. In chemical control experiment, seed treatment with Bavistin (2.5g) + foliar sprays of Indofil M-45 (0.2%) were found best in controlling the cumin blight followed by Kitazin (0.2%), Blitox-50 (0.2%) and Kavach (0.2%). Seed treatment with Bavistin (2.5 g) + foliar application of plant extracts of datura and garlic clove (25%) or bioagents (T. viride, T. harzianum and P. fluorescens) also help in reducing the cumin blight but comparatively less effective in comparison to fungicidal sprays.
Open Access
Variability studies in bipolaris sorokiniana (Sacc.) shoem causing leaf blight of wheat
(CCSHAU, 2005) Chauhan, Prashant Kumar; Karwasra, S.S.
Bipolaris sorokiniana (Sacc.) Shoem (Teleomorph: Cochliobolus sativus (Ito and Kuribayashi, Drechs ex. Dastur) causes leaf blight of wheat. A total of 13 isolates of B. sorokiniana obtained from blighted leaf samples collected from different agroclimatic zones of India (NWPZ-Pant Nagar, Karnal, Hisar and Ludhiana; NEPZ-Faizabad, Dharwad, Coochbehar and Samastipur; CZ-Pune and Vijapur and NHZ-Almora). Morphological, pathological and genetic variability were studied. Nine characters were studied at morphological level of study of pathogen viz. spore and sporophore size, sporulation, per cent germination, colony growth, septation, color of cytoplasm, shape of spore, spore and sporophere color and nuclear staining. Two type of colors of spores viz. light brown and dark brown were observed whereas, sporophores showed different types of colour viz. light brown, dark brown, dark olivaceous, light to darkbrown and grayish brown. Maximum septa in spores were found in isolate BS-6, while the maximum sporophore septa were in BS-2 and BS-8. Similarly four types of cytoplasm colors i.e. light blue, blue, greenish blue and brown were observed whereas three types of shape of spores were observed namely elliptical, oblong and slightly curved. Fastest colony growth was observed in isolate BS-11 whereas, BS-5 was the slowest growing. Maximum sporulation was observed in BS-13 while minimum in BS-5. Among all spores and sporopores, the longest were in isoalate BS-8 whereas, shortest in BS-2. Isolate BS-2 showed maximum spore germination whereas, minimum in BS-1. All the spores represented high degree of variability when nuclear staining was done with ethidium bromide (2, 7-diamino-9 phenyl phenanthridium bromide). The pathological variability was studied at five characters viz. incubation period, infection response (IR), number of lesions on flag-2 leaf, necrotic area development and terminal disease severity. Differential infection response (susceptible, moderately susceptible, moderately resistant and resistant) were observed at seedling stage on differential set of five genotypes viz. Sonalika, GW322, HD2733, PBW-34 (d) and HPW184. Maximum virulence was observed in isolate BS-2 in respect to four pathological characters namely incubation period, number of lesions on flag-2 leaf, necrotic area development and terminal disease severity. Out of 20 primers, only two i.e. OPAA-15 and OPAA-16 produced the band of all 13 isolates of B. sorokiniana isolates and a high degree of variability was detected. The isolate BS-5 made a separate group when cluster analysis was done. Isolate BS-9 and BS-11 made another group and rest were in third group.
Open Access
Studies on cumin blight caused by alternaria burnsii (Uppal, Patel and Kamat)
(CCSHAU, 2005) Shyam Sunder; Mehra, Rakesh
The laboratory, screen house and field studies entitled, “Studies on Alternaria blight of cumin caused by Alternaria burnsi (Uppal, Patel and Kamat)” was conducted at Research area of Department of Plant Pathology CCS Haryana Agricultural University, Hisar during winter (rabi) season of 2004-05. The experiments were laid out in randomized block design in field and completely randomized design in lab conditions. Alternaria blight disease of cumin appears in severe form during 2004-05 crop season. Symptoms of the blight disease appears as leaf tip become necrotic, turned purple and ultimately black in colour and infection extends to all the above ground parts viz., stem parts under severe infection, no seed formation, If formed, are non-viable. Conidia with beak 20.0 to 64.5 μ and 12.0 to 20.2 μ or without beak, 3-6 transverse septate, having 6 to 8 spore chain with rounded base. Conidiophores are branched, 2-6 celled and septate. Out of 50 genotypes/varieties of cumin screened against Alternaria blight under field and screen house conditions, none was found highly resistant and resistant. However, five lines, viz., AC-167, UC-342, RZ-209 (2001), UC-198, UC-216 were moderately resistant under both the conditions. Rest of the lines showed susceptible to highly susceptible reaction. Out of four dates of sowing early sown (20th Oct.) and late sown (5th Dec) crop showed less disease severity as compared to 5th Nov. 2004 and 20th Nov. sown crop. Maximum disease severity was in the crop sown on 5th Nov. Among the four varieties highest disease severity was observed in RS-1 variety and least disease severity on variety GC-3 on all the dates of sowing. Both the temperatures, morning (7.5-12.90C) and evening (21-240C) and relative humidity (91-95%) play a major role in the disease development. Regression equations have been developed for 4 varieties. Among the 10 plant extracts evaluated against Alternaria burnsii, datura and garlic plant extracts were found best followed by neem and aak plant extracts. Among four fungal antagonists evaluated in vitro against Alternaria burnsii, Trichoderma viride, T. harzianum were found most effective. Among bacterial antagonists, Pseudomonas fluorescens showed good control. In chemical control experiment, seed treatment with Bavistin (2.5g) + foliar sprays of Indofil M-45 (0.2%) were found best in controlling the cumin blight followed by Kitazin (0.2%), Blitox-50 (0.2%) and Kavach (0.2%). Seed treatment with Bavistin (2.5 g) + foliar application of plant extracts of datura and garlic clove (25%) or bioagents (T. viride, T. harzianum and P. fluorescens) also help in reducing the cumin blight but comparatively less effective in comparison to fungicidal sprays.
Open Access
Epidemeology and management of mungbean anthracnose caused by colletotrichum truncatum (Schw.) andrus and moore
(CCSHAU, 2006) Bhardwaz, Sudhakar; Khirbat, S.K.
Studies on epidemiological and disease management through non-conventional chemicals as well as bioagents were carried out with Colletotrichum truncatum causing anthracnose of mungbean. The disease development was maximum when the temperature and relative humidity were 30ºC and 90-100 per cent respectively in vitro. Pre and Post inoculation moist period studies revealed that minimum post inoculation moist period for initiation of disease was 12 hours with maximum infection at 72 hours. However, pre inoculation moist period resulted in increased infection but was not as effective as post inoculation period for disease development under screen house conditions Trichoderma viride was most effective in reducing the growth of the pathogen. In studies with non-conventional chemicals salicylic acid at the concentration of 5mM induced resistance in plants and gave 74.36 and 83.33 per cent disease control over check in susceptible and resistant variety under screen house conditions. Least reduction in disease control was recorded when zinc sulphate and magnesium sulphate sprayed. Biochemical analysis studies indicated that there was pronounced increase in total phenol content in resistant and susceptible varieties when sprayed with salicylic acid at 5mM concentration. However, total and reducing sugars were significantly decreased in resistant as well as susceptible variety when sprayed with non-conventional chemicals and fungicide at 24 and 48 hours after pathogen inoculation. There was sharp decrease in total sugar with salicylic acid spray at 48 hours after pathogen inoculation. Electrolyte leakage was more pronounced in resistant variety as compared to susceptible variety with salicylic acid spray at 5mM concentration. Out of twenty one mungbean lines screened against this disease under artificial disease stress conditions, two lines viz. IPM 99-125 and TM 2000-58 were found to be moderately resistant to this disease.

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