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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 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 Studies on epidemiology, variability and management of bakanae disease (Fusarium moniliforme Sheldon) of aromatic rice (Oryzae sativa L.)(CCSHAU, Hisar, 2023-08-04) Vikram Singh; Ashwani KumarBakanae of aromatic rice is one of the most destructive disease which appear in Haryana and adjoining states especially in early transplanted rice crop. The present studies were undertaken on “epidemiology, variability and management of bakanae disease during kharif 2021 to kharif 2022”. A total of 64 isolates were collected during roveing survey in kharif 2020 and 2021 from commonly aromatic rice grown area of Haryana state. Isolates were characterized on the basis of cultural and morphological characteristics on potato dextrose agar (PDA), showed white, milky white to creamy white colour on surface and cottony to cottony fluffy texture. Three isolates showed macro-conidia whereas, rest of isolates showed micro-conidia. The macro-conidia size ranged between (22.36-28.09) × (3.01-4.71) μm in length and breadth, respectively. The size of micro-conidia ranges between (4.80- 9.92) × (1.42-2.71) μm. The growth rate of isolates varied between 12.95-25 mm/48 hrs. Molecular variability among 26 selected isolates was assessed by using different molecular primers viz. β-tubulin, Tef 1 α, Vertf and rp 32 & rp 33, SSR, ISSR, URP and RAPD. Out of forty one tested primers, 18 showed amplification and 100 % polymorphism. Among SSR, URP and RAPD, ISSR primers, polymorphic information content (PIC) values ranged between 0.28-0.99, 0.35-0.39 and 0.30-0.39, respectively. Cluster analysis divides the 26 isolates into nine groups with the genetic similarity coefficient of 43.5. Among the biochemical constituents (mg/g of dry mycelium) total sugars, phenols, free amino acid and protein content varied between 3.77 (FM 53) - 12.08 (FM 63), 3.21 (FM 59) - 11.98 (FM 20), 26.31 (FM 25) - 58.83 (FM 53), 70 (FM 36) - 112 (FM 40), respectively. Amongst weather parameters during kharif 2021 maximum temperature (Tmax) and relative humidity morning (RHM) among all seasons showed positive correlation and minimum temperature and wind velocity showed negative correlation with bakanae per cent disease incidence. Coefficient of determination (R²) values ranged between 0.85 to 0.99. Among fungicides, carbendazim 50 WP was found most effective at 50 ppm under lab conditions. Among bioagents evaluated under nursery and field conditions, Trichoderma viride (WP) showed better results. Out of 46 genotypes screened under artificial inoculation field conditions, 22 were resistant, 17 were moderately resistant, 4 were susceptible and 3 were highly susceptible. Under nursery conditions, out of 61 genotypes, 35 were resistant, 23 were moderately resistant, two were susceptible and one was highly susceptible based on two year data.ThesisItem Open Access Studies on host-pathogen interaction and epidemiology of stripe rust of bread wheat incited by Puccinia striiformis f. sp. tritici West.‖(CCSHAU, Hisar, 2023-07-21) Leharwan, Munish; Rajender SinghThe experiment entitled, ―Studies on host-pathogen interaction and epidemiology of stripe rust of bread wheat incited by Puccinia striiformis f. sp. tritici West‖ was conducted at CCS Haryana Agricultural University (CCS HAU), Hisar and ICAR-Indian Institute of Wheat and Barley Research, Karnal and its Regional Station, Flowerdale, Shimla., during Rabi season of 2022-23. In present investigation, eleven genotypes and four varieties namely, SABWGPYT-2005, SABWGPYT-3017, SABWGPYT-1015, SABWGPYT-2041, SABWGPYT-1009, SABWGPYT-1004, SABWGPYT-1026, SABWGPYT-1039, SABWGPYT-2044, SABWGPYT-2040, SABWGPYT-1010, WH1270, WHD948, WH896 and WH1124 showed higher degree of slow rusting/adult plant resistance. There were 31 genotypes and 1 variety which showed promising slow rusting/adult plant resistance to stripe rust at field conditions of Karnal and Hisar. Four wheat genotypes and one variety namely, SABWGPYT-2046, SABWGPYT-1009, SABWGPYT-1004, SABWGPYT-2016 and WH896 were found very resistant to pathotypes (46S119, 110S119, 110S84 and 47S103). A total of one hundred ten wheat germplasm were screened for 44 Yr genes with 54 specific linked Primer sets. Among 44 Yr gens, 32 genes were amplified the loci associated with Yr genes. Genes, Yr32 (0.9%), Yr18 (1.81%), Yr65 (4.54%), Yr36 (5.45%), Yr44 and Yr61 (6.36%) and Yr57 (10%) showed low frequency in wheat germplasm, while Yr5 and Yr35 (95.45%), Yr64 (92.72%), Yr46 (91.91%), Yr7 (89.09%), Yr67 (88.18%), Yr51 (86.36%) and Yr62 (85.45%) were most frequent in wheat germplasm. Temperature greatly influenced the stripe rust urediospores germination. The maximum per cent spore germination was 62.44, 56.72 recorded in case of pathotype 46S119 and 110S119 respectively at 12°C and it was 56.28 per cent for pathotype 110S84 at 15°C. Weather parameters significantly influence the stripe rust development and rust progress was greatly affected due to temperature, relative humidity and rainfall. In month of February maximum development of stripe rust was observed at Karnal and Hisar. The positive correlation of stripe rust severity was observed with temperature (maximum and minimum), relative humidity (evening) and total rainfall. Regression analysis indicates the variability in stripe rust severity up to 87 percent with average temperature at Karnal and 85 percent at Hisar, respectively.ThesisItem Open Access Isolation, screening and evaluation of arbuscular mycorrhiza for the management of tomato wilt caused by Fusarium oxysporum f. sp. lycopersici(Chaudhary Charan Singh Haryana Agricultural University hisar, 2022-11) Sarita; Narender SinghInvestigations were carried out on isolation and screening of arbuscular mycorrhiza on tomato wilt cause by Fusarium oxysporum f.sp.lycopersici.Samples for the investigation were collected from the tomato fields of COA, Bawal and its adjoining area and the vegetable farm of Hisar (also adjoining area) for collection of rhizosphere soils of tomato for isolation of mycorrhizal spores. Among all these samples total of 20 isolates (HM-1 to BM-10) were selected for further study. Mycorrhizal fungi were maintained on wheat (Triticum aestivum) and pearl millet (Pennisetum typhoides). In soil, the sporocarp population was highest in Glomus fasciculatum (8774), while mycorrhizal colonization was more in Glomus mosseae (96.1 %) among all the treatments. Effect of the mycorrhizal species (Glomus fasciculatum, Glomus mosseae, Glomus intraradices and Glomus hoi) and isolates (HM-1 to BM-10) were observed on growth parameters (plant height, fresh shoot weight and fresh root weight), mycorrhizal per cent colonization and sporocarp number and NPK content of tomato plants and found that all the treatments were significantly superior as compared to uninoculated control. Maximum plant height (48.4cm), shoot weight (14.63g) and root weight (4.53g) were found in isolate BM9. Hence, isolate was selected for further experiments. A negative effect was observed on the viability of different mycorrhizal species (Glomus mosseae, Glomus fasciculatum, Glomus hoi and Glomus intraradices) uncoupled from the host. After 7 months of shoot removal minimum and significant lowest viability was observed in Glomus intraradices (35.4 %) and the maximum was in Glomus mosseae (40.1 %) (2020). During 2021, minimum and significant lowest viability was observed in Glomus intraradices (32.9 %) and the highest in Glomus hoi (39.2 %). Maximum mycorrhizal population (Mycorrhizal colonization and sporocarp number), plant growth parameters (plant height, fresh weight of shoot and fresh weight of root and dry weight of shoot and dry weight of root), Mycorrhizal inoculation effect and mycorrhizal dependency was found in onion which was sequential crop after tomato as compared to without sequential crop rotation. Effect of different treatments on wilt intensity of tomato was observed in screen house conditions and maximum wilt intensity was found in Fusarium oxysporum (75.27 %) inoculation followed by Fusarium oxysporum→ Mycorrhiza (52.47 %). Wilt disease of tomato was most effectively managed (61.30 %) by combinational application of mycorrhiza, vermicompost, FYM and spent mushroom substrate mushroom substrate recession of decreased total soluble proteins and sugars and boost of total phenol was noted in F. oxysporum inoculated plants.ThesisItem Open Access Studies on plant parasitic nematodes associated with Kinnow in Haryana and their management(Chaudhary Charan Singh Haryana Agricultural University hisar, 2022-05) Sujata; Kanwar, R. S.Present investigations were carried out for studying plant parasitic nematodes associated with Kinnow in Haryana and their management. Survey of Hisar, Fatehabad and Sirsa districts conducted during 2019-20 and 2020-21 revealed the occurrence of four major plant parasitic nematodes viz., Tylenchulus semipenetrans, Helictylenchus dihystera and Hoplolaimus indicus in Kinnow orchards. Among them, H. dihystera had highest frequency of occurrence (90.1%) but T. semipenetrans was the most dominant species. It had 45.6, 57.1, 97.7 per cent frequency of occurrence, relative density and absolute density, respectively. In all the three districts, H. dihystera had the highest frequency i.e., 72.4, 80, 70.3 per cent in Hisar, Fatehabad and Sirsa, respectively. Citrus nematode had maximum frequency (62.9 %) form Sirsa district. Correlation of T. semipenetrans with electrical conductivity (r = 0.07NS), soil pH (r = 0.22 NS), soil organic matter (r = 0.21 NS) and orchard age (r = 0.30 NS) were non-significant. Correlation between Pratylenchus coffeae and ecological factors were also non singnificant i.e., for EC (r=0.23), soil pH (r = 0.30), soil organic matter (r = -0.22), orchard age (r = 0.24). Population of H. dihystera showed no correlation with soil organic matter, weak positive correlation with EC (r = 0.17NS) and pH (r = 0.14NS) and moderate positive correlation with orchard age (r = 0.38NS). Similarly, H. indicus correlations with ecological factors were non-significant. Seasonal fluctuation and vertical distribution of plant parasitic nematodes associated with Kinnow was studied at four locations viz., Horticulture research farm, CCS HAU, Hisar, Malapur, Nangthala and Arya nagar. Maximum number of phytonematodes were recorded in November (2020) followed by March (2021) and lowest in July (2021). More number of nematodes were present at 15-20 cm soil depth as compared to 21-30 cm and 31-45 cm depth. Experiments on management were done at Malapur during 2020-21 and at Horticulture research farm, CCS HAU, Hisar during 2021-22. Application of neem cake @ 1.5 kg, T. viride @ 200 g and neem cake @ 1 kg with T. viride @ 100 g per plant significantly reduced the nematode population and increased the yield significantly over control.
