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Chaudhary Charan Singh Haryana Agricultural University, Hisar
Chaudhary Charan Singh Haryana Agricultural University popularly known as HAU, is one of Asia's biggest agricultural universities, located at Hisar in the Indian state of Haryana. It is named after India's seventh Prime Minister, Chaudhary Charan Singh. It is a leader in agricultural research in India and contributed significantly to Green Revolution and White Revolution in India in the 1960s and 70s. It has a very large campus and has several research centres throughout the state. It won the Indian Council of Agricultural Research's Award for the Best Institute in 1997. HAU was initially a campus of Punjab Agricultural University, Ludhiana. After the formation of Haryana in 1966, it became an autonomous institution on February 2, 1970 through a Presidential Ordinance, later ratified as Haryana and Punjab Agricultural Universities Act, 1970, passed by the Lok Sabha on March 29, 1970. A. L. Fletcher, the first Vice-Chancellor of the university, was instrumental in its initial growth.
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ThesisItem Open Access Cultural studies and genetic approaches for management of Rhizoctonia solani Kuhn f. sp. sasakii (Exner) causing banded leaf and sheath blight in maize(CCSHAU, Hisar, 2022-07) Poonam Kumari; Prashant Kumar ChauhanThe necrotrophic fungal pathogen Rhizoctonia solani is one of the highly destructive soil-borne pathogen distributed worldwide, responsible for causing banded leaf and sheath blight (BLSB) in maize. In Haryana, BLSB is the major constraint of maize, in reducing the yield during kharif season. Keeping in view the enormous losses caused by the disease and its regular appearance in severe form the present investigation has been devised on cultural, morphological and molecular variability among different isolates of pathogen collected from major maize growing regions of Haryana. Eighteen isolates of R. solani associated with maize crop were collected from different locations of Haryana and nearby of New Delhi. The variations among isolates in colony diameter, growth rate, growth pattern, colony colours, texture, hyphal characters, number of nuclei, sclerotial characters including position, colour, texture, size, number, weight and honey dew were observed in all the isolates and are grouped on the basis of variations exhibited. The hierarchical cluster analysis differentiated all R. solani isolates into five major cluster (C1- C5) based on cultural, sclerotial and morphological characters. Molecular analysis confirmed that all the isolates belonged to R. solani species and all isolates exhibited relation with anastomosis subgroup AG1-IA. The results of study confirmed that anastomosis subgroup AG1-IA belongs to maize crop causing BLSB disease is the most predominant and geographically distributed in Haryana and nearby location of New Delhi. Pathological study revealed that nine maize genotypes viz. HKI 161, HKI 163, HKI 164-7-6, HKI 193-2, HKI 194-7, HKI 288-2, HKI 488, HKI 1128 and IQPMH-18-2 were resistant for BLSB. The results clearly depicted that high genetic diversity exist among the genotypes of maize and polymorphism on the basis of SSR markers was observed. Molecular analysis differentiated thirty-eight maize genotypes into two main clusters viz. cluster-I and cluster-II with similarity coefficient 61%. The cluster-II consisted of only one genotype HKI 1653 SER-4 which was observed as the most diverse genotype among all the thirty-eight genotypes. Two SSR markers phi035 and bnlg1065 were identified as specific to resistance for BLSB. Present study revealed the existence of high variability in R. solani isolates at cultural, morphological and genetic level. The variability was present among the maize genotypes for resistance against R. solani causing banded leaf and sheath blight in maize and all R. solani isolates of BLSB belongs to anastomosis subgroup AG1-IA.ThesisItem Open Access Studies on seasonal cultivation of Schizophyllum commune (Fries) medicinal mushroom in Haryana(CCSHAU, Hisar, 2023-06) Jain, Sourabh; Jagdeep SinghSchizophyllum commune (Fries) is a valuable medicinal mushroom. Various factors such as growth media, temperature regimes, and pH levels were examined to determine the optimal conditions for its mycelial growth. The most suitable growth medium was potato dextrose agar (PDA). The ideal temperature range for mycelial growth was found to be 30±1˚C, while the optimal pH level was 5, although the mushroom can tolerate temperatures between 30-35˚C and pH levels of 4-6. When evaluating different combinations of substrates and supplements, it was observed that the mycelia grew faster when a mixture of wheat straw and sawdust (1:1) was supplemented with 10 per cent wheat bran. Among the four base materials tested for spawn production, sorghum grains were the most suitable. In March 2023, a study was conducted on the cultivation of S. commune using a substrate consisting of wheat straw and sawdust supplemented with wheat bran. The substrate was amended with 3 per cent calcium sulphate and 1 per cent calcium carbonate, filled into polypropylene bags, sterilized, and inoculated with spawn made from sorghum grains (2 per cent). The bags were placed in a dark mushroom house with a temperature of 30±1˚C, high carbon dioxide levels, and a relative humidity of at least 80 per cent. This cultivation method resulted in optimal spawn growth, pinhead formation, fruit body production, yield, and biological efficiency. Three flushes of mushrooms were obtained during the 37-day crop cycle, and a biological efficiency of 15 per cent was achieved using the supplemented substrate mixture throughout the cropping season.ThesisItem Open Access Epidemiology and induction of systemic resistance in sorghum against Cercospora sorghi (Ellis & Everh.) causing grey leaf spot(CCSHAU, Hisar, 2023-05) Janvi; Manjeet SinghThe grey leaf spot disease of sorghum (Sorghum bicolor L. Moench.) caused by Cercospora sorghi has emerged as a seriousprobleminmost ofthe sorghumgrowingplaces of India,leadingtoconsiderableyieldlosses. The present investigation on epidemiology, management and biochemical analysis were carried out during Kharif 2022-23. Epidemiology of the pathogen was studied under field condition in two varieties (HC 136 and CSV32F) of sorghumby sowing the cropatthreedifferentdates. Outofthethree datesof sowingof sorghum,higherdisease severity,AUDPC andAIR was observed on early sown crop (15thJune) followed by normal sown crop (30th June) and least in late sown crop (15th July) on both the varieties. Disease severity,AUDPC andAIR was higher in HC 136 as compared to CSV32F in all three dates of sowingduring Kharif 2022.Temporal increasewas maximumin 30th to 31st standard meteorological week (SMW) followed by 38th to 39th SMW in both the varieties. The inhibitory effect of chemical inducers was evaluated against Cercospora sorghi under in vitro conditions and maximum mycelial growth inhibition was recorded in salicylic acid followed by indole butyric acid. Among the biorational components evaluated against C. sorghi, neem leaves extract at 20 per cent concentration and Trichodermaharzianumandwerefoundthemost effectiveinmyceliumgrowthinhibitionofthepathogenunder in vitro conditions. Out of eight fungicides evaluated against C. sorghi, under in vitro conditions, Carbendazim 50% WP and Propiconazole 25% EC at 50 µg/ml were found most effective. Under screen house conditions, salicylic acid showed maximum per cent disease control at 100 µg/ml concentration in both the variety i.e., HC 136 (susceptible) and SH 1951 (moderately resistant). The analysis of biochemical parameters like determination of total phenol content and different enzyme activities i.e., Polyphenol Oxidase (PPO), Phenylalanine AmmoniaLyase(PAL)andTyrosineAmmoniaLyase(TAL)revealedsignificantresults.Totalphenolswerefoundmaximum in plants inoculated with conidial suspension of Cercospora sorghi and increase from 0 to 96 HAI. But in other treatments it increased upto 72 HAI and then decreased in both the varieties and being higher in SH 1951. The enzyme activities were higher in plants sprayed with salicylic acid. Polyphenol Oxidase (PPO) activity continuously increased from 0 to 96 HAI in all treatments. Phenylalanine Ammonia Lyase (PAL) and Tyrosine AmmoniaLyase(TAL)activitiesincreased upto48HAIand thendecreased from48 to96HAIin alltreatmentsof both varieties. Among the best promising non conventional chemicals, botanicals, bioagents and fungicides, carbendazim 50% WP and Propiconazole 25% EC at 50 µg/ml were found under field conditions. Out of eighty five varieties of sorghum screened against grey leaf spot, twenty three and twelve varieties were highly resistant and resistant respectively. For sorghum, which is grown as fodder crop, fungicides are often not advised due to their residual impact, therefore use of chemical inducers to induce systemic resistance in plants and integrated approaches for management of grey leaf spot is, therefore, a high-priority research area.ThesisItem Open Access Studies on morpho-molecular characterization, epidemiology and management of Rhizoctonia solani f. sp. sasakii Exner causing banded leaf and sheath blight of maize(CCSHAU, Hisar, 2023-03-09) Parvesh Kumar; Mehra, RakeshBanded leaf and sheath blight (BLSB) caused by Rhizoctonia solani f. sp. sasakii has emerged as an economically important disease in most of maize growing areas of India, leading to considerable qualitative and quantitative losses in maize. The present investigation on survey and surveillance of banded leaf and sheath blight, epidemiology, management and morpho-metric, pathogenic, molecular characterization were carried out with fifty one R. solani isolates collected from different geographical locations of India. Occurrence of banded leaf and sheath disease intensity ranges from 4.47-55.62 per cent in major maize growing districts of Haryana during kharif 2020 and 2021. Maximum disease severity (55.62%) was in Panchkula, followed by Karnal (41.84%), Sonipat (39.96%), Ambala (32.66%), Kurukshetra (23.20%) and Yamunanagar (21.89%). Significant variations was observed among fifty one R. solani isolates on the basis of cultural and morphological characters and hierarchical cluster analysis differentiated all R. solani isolates into five major cluster (C1- C5). Molecular analysis confirmed that all the isolates belonged to R. solani species exhibited relation with anastomosis subgroup AG1-IA belong to maize crop causing BLSB disease and also in maize cultivated lands. In the pathogenic variations, isolates RS 29 from New Delhi and RS 1 from Karnal were found highly virulent. Out of four dates of sowing of maize, the highest disease intensity, AUDPC and AIR was observed in 1st date of sowing (16 June) followed by 2nd date of sowing (30 June), 3rd date of sowing (14 July) and least in 4th date of sowing (28 July) in all the seven maize hybrids. Maximum temperature range of (31.39-33.23°C), minimum temperature (25.36-26.73°C) with morning relative humidity (93.43-96.79%) and evening relative humidity (71.17-87.37%), rainfall (1.98-10.21 mm) and sunshine (4.90-7.47 h/day) were most congenial for disease development. Temporal progression was maximum in 34th to 35th and 37th to 38th meteorological weeks in seven maize hybrids. Temperature and relative humidity are the major components responsible for disease development and progression. Regression equation on relationship between disease development and weather parameters have been developed for seven maize hybrids. R2 value of regression equation in relation to weather parameters could comprise of disease level up to 96 to 98 per cent. Among seven maize hybrids, maximum AUDPC was recorded in QPM 9 and minimum in HQPM 4 in all the four dates of sowing. However, mean AUDPC of four dates of sowing were more in kharif 2021 as compare to kharif 2020 in maize hybrids QPM9, HQPM 4, HQPM 1 and HSC I. Mean AIR of four dates of sowing was highest in QPM 9 and minimum in HQPM 4 during both the years. Out of five hundred and seventy two maize genotypes (hybrids/inbred) screened against BLSB under artificial inoculated conditions, sixteen maize genotypes were resistant. Among sixteen plant extracts garlic, eucalyptus and pudina were most effective at 20 % concentration both in vitro and in vivo conditions. Under in vitro conditions bio agent Trichoderma sp. 1 was highly effective with 73.06 per cent mycelium growth inhibition followed by Trichoderma sp. 2 (59.72%) while, in vivo conditions T. viride was most effective and gave 33.32 per cent disease control followed by T. harzianum (27.86%). The fungicides fluxapyroxad 167 g/L + epoxiconazole 333 g/L SC, pyraclostrobin 13.3% + epoxiconazole 5% SE and propiconazole 25% EC were most effective both in vitro and in vivo conditions. In integrated management, out of eleven treatments, application of soil amendment of Trichoderma formulation @ 6T/acre FYM+ seed priming with salicylic acid @100 μg ml-1 + foliar sprays of azoxystrobin 2%+ difenoconazole 11.4% @ 0.1% and neem extract @1% was most effective against BLSB of maize.ThesisItem Open Access Studies on management of ashwagandha wilt and host-microbiome interaction with its incitant (Fusarium spp.)(CCSHAU, Hisar, 2023-01) Abhishek Kumar; Kushal RajWilt caused by Fusarium solani is major disease of ashwagandha in India leading to significant losses. Management of disease using bacterial endophytes and arbuscular mycorrhizal fungi is considered an eco-friendly and viable alternative to synthetic fungicides. The present study was carried out to explore the efficacy of bacterial endophytes retrieved from ashwagandha roots and arbuscular mycorrhizal fungal (AMF) cultures for Fusarium wilt management. Amongst 32 bacterial endophytic isolates screened against Fusarium solani under in vitro conditions, three isolates identified as Pseudomonas putida, Pseudomonas aeruginosa and Pseudomonas sp. Strain HH170 exhibited significantly higher antagonistic activity i.e. 89.06%, 86.76% and 83.09% respectively against F. solani. Under screen house and field conditions all three promising endophytic bacteria were also found promising for growth attributes as well as managing wilt of ashwagandha. Amongst different treatments, seed treatment with combination of Carboxin 37.5% + Thiram 37.5 WS @ 4 g/kg. seed followed by endophytic bacterial culture suspension (108 cells/ml) @5 ml/kg seed exhibited maximum plant disease management under both screen house and field trials. Amongst four AMF cultures, i.e., Glomus mosseae, Glomus fasciculatum, Glomus intraradices and Glomus hoi inoculation with Glomus mosseae @ 600 spores/kg soil was found best for wilt incidence reduction, plant growth enhancement as well as boosting the nutrient content in ashwagandha roots. On the basis of various experiments, it was found that the combination of Carboxin 37.5% + Thiram 37.5 WS @ 4 g/kg. seed followed by application of endophytic bacterial culture suspension (108 cells/ml) @5 ml/kg seed and Glomus mosseae @600 spores/kg soil could be used as eco-friendly and viable option for wilt management and growth promotion in ashwagandha.ThesisItem Open Access Studies on variability and management of rhizoctonia spp. inciting root rot disease of cotton(CCSHAU, Hisar, 2023-10) Preeti; Yadav, N. K.The present study entitled, “Studies on Variability and Management of Rhizoctonia spp. Inciting Root Rot Disease of Cotton” was carried out in Department of Plant Pathology, CCS Haryana Agricultural University, Hisar and RRS, Bawal. The study was aimed to know the occurrence and incidence of cotton root rot disease in Haryana, morphological, molecular and pathogenic variability among R. bataticola and R. solani isolates and and management of Rhizoctonia spp. through fungicides, botanicals and native Trichoderma isolates. The maximum cotton root rot disease incidence was recoded in Fatehabad district followed by Sirsa district, whereas; minimum was in Charkhi Dadri district during both the year 2021 and 2022. Among all the isolates the maximum radial growth 69.33 mm was recorded in isolate RB5 followed by RS2 (59.00 mm) and RB8 (52.00 mm) whereas, the minimum radial growth of 32.33 mm was recorded in RB3 isolate (32.33). Maximum mycelial width was recorded in isolate RS2 (7.29 μm) followed by RB6 (7.23 μm) and RB13 (6.93 μm) whereas, the minimum radial growth of 32.33 mm was recorded in RS1 isolate (3.58 μm). All the isolates showed high level of polymorphism. The cluster analysis of R. bataticola isolates based on RAPD primers, isolate RB4, RB5 and RB8 were most diverse and cluster analysis of isolates based on ISSR primers isolate RB16 was most diverse among all the isolates. The cluster analysis of R. solani isolates based on RAPD primers, isolate RS3 was most diverse. Among the fungicides evaluated under in vitro conditions against RB5 and RS2, carbendazim showed maximum inhibition of the mycelial growth (98.27% and 97.04%) of RB5 and RS2 at 200 ppm concentration which was statistically significant than other treatments. Among the botanicals evaluated under in vitro conditions against RB5 and RS2, Lantana camara showed maximum inhibition of the mycelial growth (77.14% and 75.67%) of RB5 and RS2 at 20 per cent concentration, where it was statistically significant than all other treatments followed by Parthenium hysterophorus (72.11% and 71.55%) and least was showed by ginger (24.61% and 22.75%) respectively. Evaluation of native Trichoderma isolates against Rhizoctonia spp. under in vitro conditions revealed that HST2 showed maximum antifungal activity with 72.78, 72.50 per cent growth inhibtion against RB5 and RS2 respectively and statistical significant than other native isolates. As far as biocontrol activities are concerned, HST2 showed positive results for HCN production, IAA production, siderophore production, cellulase activity, pectoloytic avtivity, ammonia production, Zn solubilisation and phosphate solubilization. In vivo evaluation of fungicides, botanicals and bio-agents, it was observed that they significantly reduced the disease incidence of root rot during Kharif, 2021 and Kharif 2022 and maximum disease control was achieved by carbendazim and significantly higher with other fungicides in both Desi and American cotton. Among botanicals under study during Kharif 2021 and Kharif, 2022, maximum disease control was recorded by Lantana camara which significantly differed with other botanicals in both Desi and American cotton. Different Trichoderma isolates showed the wide range of antagonistic activity against R. bataticola and R. solani. Maximum disease control was showed by native Trichoderma isolates i.e., HST2 followed by HMT2 during both the years of experiments.ThesisItem Open Access Studies on pearl millet endophytic bacteria in fending off Magnaporthe grisea M.E. Barr, inciting blast disease of pearl millet [Pennisetum glaucum (L.) R. Br.](CCSHAU, Hisar, 2023-10) Verma, Preety; Vinod KumarPearl millet (Pennisetum glaucum (L.) R.Br.) is the oldest cultivated drought tolerant warm season coarse grain crops of Asian and African countries. Pearl millet is affected by many diseases among them, blast disease incited by Magnaporthe grisea M.E. Barr, is one of the destructive diseases of pearl millet. Endophytic bacteria are thought to interact closely with their host plants, and therefore could be used as biological control agents in sustainable crop production potentially. In the present study, Plant parts were collected from Plant Pathology field during Kharif 2021. A total of 38 pearl millet endophytic bacteria were retrieved from root, stem and leaves of pearl millet streaked on Nutrient agar plates. Maximum number of Pearl millet endophytic bacteria in the roots (16), followed by stem (12) and minimum found in leaves (10) whereas, leaves exhibited the highest total phenolic content, Orthodihydroxy phenols, Total soluble sugars and protein content, followed by the stem and the root. Peroxidase activity, Polyphenol oxidase and Catalase activity was highest in the root, followed by the stem and leaves. Amongst 38 pearl millet bacterial endophytes, twelve isolates were positive for siderophore production, 11 isolates were found positive for HCN production, 13 bacterial endophytes showed good growth on ACC supplemented plates, eighteen showed positive cellulolytic activity, 13 bacterial isolates indicate the presence of Ammonia production and five showed the zn solubilization. For further evaluation against pathogen, promising endophytes PMREB 1, PMREB 4, PMREB 8, PMSEB 3, PMSEM 7, PMSEB 10, PMLEB 2, PMLEB 4 and PMLEB 6 were selected on the basis of bio-control activities. Out of which, PMLEB 8 showed the minimum mycelial growth (31.6) followed by the maximum growth inhibition (%) (64.8) which is at par with the PMREB 8 showed minimum mycelial growth (35.7) having the growth inhibition percentage 60.2%. Under field conditions, results showed that T24 (Seed treatment + Foliar spray with PMLEB 2 + PMLEB 6+ PMLEB 8) showed minimum percent disease incidence at 60 DAS (46.11 %), which is at par with the T18 (Seed treatment with PMREB 1 + PMREB 4+ PMREB 8) showed the minimum percent disease incidence at 60 DAS that is 47.15%. T24 ( Seed treatment + Foliar spray with PMLEB 2 + PMLEB 6+ PMLEB 8) showed the best result having the maximum yield 1,251.30 Kg/ ha with the test weight 9.65g which is at par with the T18 (Seed treatment with PMREB 1 + PMREB 4+ PMREB 8 ) showed the yield 1,187.08 Kg/ha with test weight 9.65g. Based on morphological, biochemical and molecular characterization, the endophytes PMLEB 8 were identified as Bacillus niabensis strain 45 (Accession no. OR094470), PMREB 8 were identified as Pseudomonas geniculata strain IAE94 (Accession no. OR095169) and PMREB 4 were identified as Bacillus sp. Marseille-Q1617 (Accession no. OR095898). Promising endophytes may be used for IPM of blast disease in pearl millet after field trials.ThesisItem Open Access Variability and management of Colletotrichum gossypii Southw., the incitant of anthracnose disease of cotton(CCSHAU, Hisar, 2023-03) Yadav, Lokesh; Yadav, Naresh KumarThe present investigation entitled, “Variability and management of Colletotrichum gossypii Southw., the incitant of anthracnose disease of cotton” was conducted during Kharif, 2020 and 2021 at CCS Haryana Agricultural University, Hisar. This investigation was aimed to study cultural, morphological and molecular variability among different isolates of Colletotrichum gossypii; to manage pathogen under in vitro and in vivo conditions and to screen cotton genotypes for disease resistance. Anthracnose disease of cotton caused by Colletotrichum gossypii is becoming serious impediment and limiting factor for reduced quality and quantity of produce. All the collected C. gossypii isolates showed a significant variation in cultural, morphological and molecular characteristics. The maximum mean radial growth was recorded for COG 5 isolate i.e., 52.20 mm, whereas minimum radial growth of 29.20 mm was recorded in COG 13 isolate. Most of the collected isolates have shown whitish-creamy and whitish to grey colony colour except COG 13 which showed whitish to pink colour. The size of conidia varied from 8.58-11.41 μm × 3.39-4.54 μm. The COG 5 isolate recorded maximum mycelial width (4.37 μm), while minimum mycelial width was observed in COG 13 (2.89 μm). ITS region, TUB region and species specific SNP primers successfully identified and confirmed C. gossypii, and ISSR primers grouped all isolates into two major clusters at a similarity coefficient of 0.67 depicting the genetic variability among 13 isolates of C. gossypii. The extract of garlic cloves recorded maximum growth inhibition (83.96%) under in vitro conditions. Trichoderma harzianum recorded maximum mycelium growth inhibition (65.37%) among five biological control agents. The maximum mean mycelial growth inhibition was recorded by azoxystrobin 18.2% + difenoconazole11.4% SC i.e., 90.48 per cent among all the seven evaluated fungicides. Amongst four tested fungicides under field conditions, maximum mean disease control during Kharif 2020 and 2021 was recorded by azoxystrobin 18.2% + difenoconazole 11.4% SC @ 0.1 % i.e. 78.21 and 75.80 per cent in RCH 773 and H1098i, correspondingly with highest cotton yield of 2590.26 and 2105.29 kg/ha in cotton cultivars RCH 773 and H1098i, respectively. The maximum disease control was recorded by garlic cloves extracts i.e. 62.50 and 60.92 per cent in RCH 773 and H1098i, respectively with maximum yield in RCH 773 (2436.62 kg/ha) and H1098i (2018.18 kg/ha) during Kharif, 2020 and 2021. Among all the 131 germplasm lines which were screened against cotton anthracnose disease, sixty four genotypes exhibited moderately resistant reaction.ThesisItem Open Access Epidemiology and management of Alternaria leaf spot of Bael incited by Alternaria alternata (Fr.) Keissler(CCSHAU, Hisar, 2023-05) Deepak; Manoj KumarThe present investigation entitled “Epidemiology and management of Alternaria leaf spot of Bael incited by Alternaria alternata (Fr.) Keissler” was conducted in the laboratory in department of plant pathology, COA, Hisar and research farm of Regional Research Station, Bawal, CCS HAU during 2022-23. Characteristic symptoms were observed on leaves as concentric circles in the centre of the leaf spots surrounded by a chlorotic yellow halo. The presence of brown to black necrotic lesions on older leaves that produce a bulll’s eye pattern. The pathogen, A. alternata was isolated as pure culture on PDA medium. The colony appeared as black or olivaceous black and sometimes of grey color. The fungus produces conidia that are light brown, having muriform shape with both cross and longitudinal septa and having conical or cylindrical beak of 2 to 5 µm thickness. The average size of the conidia was 25-60 x 10-16 µm and the conidiophores were dark bearing a chain of conidia. Epidemiology of disease was studies under field condition revealed that significant but negative correlation was observed between per cent disease severity and temperature (minimum and maximum), average evening relative humidity (RHe), wind speed and rainfall. The average morning relative humidity (RHm) and Sun shine hours showed non-significant positive correlation with disease severity. Tmax. 28°C and relative humidity 79% were found most favourable conditions for the progression of the disease. Among four bioagents evaluated in dual culture under in vitro conditions against A. alternata, Trichoderma viride showed highest mycelial growth inhibition of 72.62 per cent followed by Trichoderma harzianum (68.43 per cent ) and Pseudomonas fluorescens (61.56 per cent) while least effective was Bacillus subtilis (54.37 per cent). Out of six fungicides/non-conventional chemicals evaluated against A. alternata, metiram 55% + pyraclostrobin 5% WG and tebuconazole 50 + trifloxystrobin 25% (75 WG) with 78.92 and 71.25 percnet mycelial growth inhibition, respectively were found most effective and significantly superior among the treatments under in vitro conditions. Under field conditions, metiram 55% + pyraclostrobin 5 % WG was found superior over other treatments with highest per cent disease reduction over control (82.43 per cent) followed by tebuconazole 50 + trifloxystrobin 25 % (75 WG) (76.83 per cent). The maximum yield was recorded in plants treated with metriam 55% pyraclostrobin 5% WG @ 0.25 per cent (63.27 kg/tree) followed by tebuconazole 50+ trifloxystrobin 25% (75 WG) @ 0.10 per cent (60.24 kg/tree). An increasing consciousness about environmental pollution due to fungicides and development of fungicide resistance in pathogen population has challenged the plant pathologist to search for eco-friendly tools for A. alternata management. The use of integrated approaches to disease management is, therefore, a high-priority research area.
