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Open Access
Biochemical changes in genetic and induced systemic resistance due to infection of Albugo candida (Pers. ex. Lev) in Indian mustard
(CCSHAU, Hisar, 2020-03) Annu; Rathi, A. S
White rust disease incited by Albugo candida is an important disease of Indian mustard (Brassica juncea) in India particularly in northern and North eastern states. Keeping in view the enormous losses caused by the pathogen, the present investigation has been devised on biochemical changes due to infection of Albugo candida in different Indian mustard genotypes, induction of systemic resistance by non conventional chemicals, identification of slow white rusting genotypes and role of micronutrients in defence against white rust under laboratory, screen house and field conditions at Chaudhary Charan Singh Haryana Agricultural University, Hisar. The results of biochemical analysis revealed that total phenolic content, PO, PPO, PAL and chitinase activity were found higher in healthy leaves of resistant genotypes (BIOYSR, EC399299) as compared to moderately resistant genotypes (EC399301, DRMRIJ-31) and susceptible genotypes (RH 30, RH 8812) at 35-40 DAS. There was steep increase in all the biochemical constituents at the time of disease initiation ie. at 45-50 DAS. However, increase was more in inoculated environment as compared to uninoculated environment. At maximum disease severity i.e.70-75 DAS, there was decline in all the biochemical constituents in all genotypes under both the environments. Decrease was more in susceptible genotypes indicating the exhaustion of these biochemical constituents which otherwise consider necessary to trigger genetic resistance through pathways. Efficacy of six non conventional chemicals were tested with different concentrations for induction of resistance against white rust. None of the non conventional chemical completely controlled the white rust disease even at higher concentration of 100 μg/ml. However, a maximum control was also recorded by BTH at 100 μg/ml concentration after six weeks of challenge inoculation by the pathogen followed by SA in both the variety (RH 30 and RH 0749) under screen house conditions. BTH has shown maximum induction of phenolic content, PO, PPO, PAL and chitinase activity at three days after inoculation (DAI) in both the varieties at 100 μg/ml concentration followed by SA. However, MgSO4 has shown minimum induction of these activities at three DAI in both the varieties.Out of 22 Indian mustard genotypes screened for identification of slow white rusting component, 9 genotypes exhibited longer incubation and latent periods, minimum number of pustules per leaf, minimum size of pustule, minimum sporulation, minimum disease severity and minimum AUDPC indicating slow white rusting behaviour. Among the different treatments of mcronutrients alone and in combinations, soil application of Gypsum + Borax + CuSO4 + Na2MoO4 at 30 DAS as basal dose recorded minimum white rust severity of 31.1% and staghead incidence of 4.44% and highest seed yield of 2228.55 kg ha-1 as compared to the 45.83% white rust severity and 6.09% staghead incidence and seed yield of 1779.79 kg ha-1 in control. Maximum number of primary branches per plant (5.83), secondary branches per plant (12.33), main shoot length (90.93 cm), siliquae on main shoot (62.60) and seeds per siliquae (12.53) were also observed with above treatment. Plant height, siliqua length, oil content and 1000 seed weight did not vary significantly among all the treatments.
Open Access
Effect of feeding different carbohydrate and pollen sources on Apis mellifera L. colonies during dearth period
(CCSHAU, Hisar, 2020-01) Rathee, Mandeep; Chaudhary, O. P
The present investigations were carried out at the apiary located at College of Agriculture, Kaul, CCS HAU, Hisar to evaluate the effect of feeding different carbohydrate sources with and without pollen on Apis mellifera L. colonies during 2017 dearth period. A total of 30 A. mellifera bee colonies in standard Langstroth hives were tested under two sets of experiments i.e. without pollen and with pollen (80 g/colony/week), and each set had five treatments [4 carbohydrates sources (500 g/colony/week): sugar syrup, jaggery, liquid glucose, high fructose rice syrup and 1 control (no feeding)]. During 2018, jaggery was ruled out and remaining carbohydrate sources were fed @ 750 g/colony/week with high protein (23%) and low protein pollen (18%). Observations were recorded on pollen income, colony growth parameters, colony weight, incidence of insect-pests, diseases and mites, robbing, bee mortality, deformities, feed consumption, chemical and organoleptic analysis of honey, survey of bee flora, melissopalynology of pollen loads, their protein content and calorific value. Economics of feeding treatments was evaluated alonth with colony performance in ensuing honey flow seasons. Based on two years of studies, it was concluded that experimental area had severe dearth of nectar and pollen providing floral plants from June to October during both the years. In the absence of feeding, A. mellifera colonies could not survive beyond 57 and 64 days during 2017 and 2018, respectively, indicating necessity of supplementary feeding during dearth periods. Sugar syrup was the most economical and effective carbohydrate source for feeding A. mellifera colonies followed by liquid glucose. Pollen supplement feeding along with carbohydrate syrups significantly improved survival and growth of A. mellifera colonies during dearth period. HFRS was comparatively less effective carbohydrate source when fed alone however; with pollen its performance improved significantly. Jaggery was the least preferred source and not at all recommended for dearth feeding, as it induced maximum mortality (27.0 to 27.7 dead bees/feeder/week), fermented faster and attracted intruders like wasps. Incidence of insect-pests, mites and diseases was lowered by proper hygiene, care and supplementary feeding during dearth periods. Inter and intra-specific robbing was characteristic feature during dearth period in A. mellifera colonies. Most of the honey quality parameters although remained within the prescribed limits but variations were recorded in HMF (3.33-26.16 mg/kg), moisture (15.87- 20.10 g/100g), F:G ratio (1.00-1.09), ash content (0.17-0.45 g/100g) and acidity (0.042-0.062 g/100g), while sucrose remained below LOQ, i.e. 0.5g/100g. Organoleptic scores revealed maximum acceptability of fresh honey (8.43-8.60) while honeys from HFRS fed colonies had the least acceptance (7.03-7.40). Seventy one different plant species belonging to 31 families were foraged by bees during dearth period. Protein content and calorific value in different pollen types ranged from 15.5-42.5% and 399.6-493.0 Kcal/100g, respectively.
Open Access
Epidemiology, induction of systemic resistance and management of charcoal rot of sesame incited by Macrophomina phaseolina (Tassi) Goid.
(CCSHAU, Hisar, 2020-01) Gupta, Ramesh Nath; Saharan, Hawa Singh
Charcoal rot disease incited by Macrophomina phaseolina (Tassi) Goid. is the most destructive disease of sesame and causes heavy losses. The disease appears moderate to severe form every year in Haryana. Keeping in view of economic importance of this disease, the present study on epidemiology, induction of systemic resistance and management has been conducted under laboratory, screen house and field conditions during kharif 2017 and 2018 at CCS HAU, Hisar. Epidemiological studies showed the onset of charcoal rot varied in varieties HT 1 and HT 2 during different dates of sowing. The disease first appeared in early sown crop with higher disease incidence; however, disease appearance was delayed in mid and late sown with lower incidence of disease. The intensity of disease in mid sown and late sown was almost similar however; rate of disease progression was higher in late sown as compared to mid sown conditions. In vitro evaluation of non-conventional chemicals, salicylic acid (SA) was found most effective in inhibiting mycelial growth of M. phaseolina followed by IAA and IBA. Under screen house conditions, SA showed maximum reduction of charcoal rot incidence than other chemicals. Similarly, under field conditions, SA enhanced the yield and yield attributing traits than other treatments. Induction of total phenol content, total sugar content, peroxidase (POX), polyphenol oxidase (PPOX), phenylalanine ammonia lyase (PAL) and catalase activity was significantly increased by the treatment of SA followed by IAA, IBA and least by riboflavin. These activities reached at peak on six days after inoculation of pathogen and afterwards declined in both the varieties. However, variety HT 2 showed higher induction of biochemical activities than HT 1. Phytoextracts were evaluated for control of disease under in vitro conditions in which garlic extract (10%) showed maximum inhibition of mycelial growth followed by onion, karanj, neem and least by lantana extract. Similarly, under screen house conditions, garlic extract more reduced the incidence of charcoal rot than other phytoextracts. Under field conditions, seed treatment with combination of fungicides (carboxin+thiram) was most effective in controlling charcoal rot disease as well as enhanced the yield and yield attributing traits. Three hundred fifty sesame germplasm lines were evaluated for their relative resistance under field conditions in which majority of them showed moderately susceptible and susceptible reaction against charcoal rot. None of them identified as resistant, whereas only eighteen lines showed moderately resistant reaction against charcoal rotdisease
Open Access
Studies on the population dynamics, monitoring, mortality and control of Bemisia tabaci (Genn.) on cotton crop
(CCSHAU, Hisar, 2020-07) Mehra, Swati; Rolania, Krishna
The present investigation entitled “Studies on the population dynamics, monitoring, mortality and control of Bemisia tabaci (Genn.) on cotton crop” was carried out during 2017 and 2019, both in the Laboratory as well as at Experimental Area, Department of Entomology, CCS Haryana Agricultural University, Hisar. The population dynamics study revealed that peak activity of whitefly and its parasitoids, Encarsia spp. was observed from April to May on brinjal, cucumber and okra; in August on greengram, soybean and okra; and in September on cotton. In descending order, the peak abundance of whitefly was observed on cotton followed by cucumber, soybean, greengram, brinjal and okra while, parasitization by Encarsia spp. was highest on soybean followed by cotton, greengram, brinjal, cucumber and okra during 2017 and 2019. A total of 46 host plants belonging to 12 families were reported to be infested by whitefly, B. tabaci. Monitoring studies revealed that peak population of whitefly adults on yellow sticky traps (14,392 whitefly adults/trap) and in direct count (19.06 whitefly adults/leaf) was recorded during 38th SMW i.e., 3rd week of September; whereas, whitefly nymphal population i.e., 31.2 per leaf by direct count method was at its peak during 39th SMW i.e., 4th week of September. In direct count, whitefly adult population showed a significant negative correlation with evening relative humidity (r = -0.53) (r = -0.56) and total rainfall (r = -0.61) (r = -0.58) during 2017 and 2019, respectively. Nymphal population showed significant negative correlation with evening relative humidity (r = - 0.52) and total rainfall (r =-0.54) in 2019. Population captured on yellow sticky traps showed no correlation with weather parameters in 2017. While, whitefly adults captured on both horizontal (r = 0.54) (r = -0.51) and vertical traps (r = 0.55) (r = -0.51) showed significant positive and negative correlation with sunshine hours and total rainfall, respectively in 2019. Across all the immature developmental stages, principal mortality governing factor was dislodgement in cotton, predation in brinjal and parasitism in cucumber crop. The highest mortality occurred during fourth nymphal instar on cotton, brinjal and cucumber. Azadirachtin 0.03 per cent @ 7.5 ml/l was found more effective against whitefly adults and nymphs. However, it remained significantly at par with Azadirachtin 0.03 per cent @ 5 ml/l (recommended dose) and Azadirachtin 0.15 per cent at the dose of 7.5 ml/l and 5 ml/l.
Open Access
Determination of pollen trapping frequency, pollen collection and hoarding behaviour in Apis mellifera L. colonies
(CCSHAU, Hisar, 2019-09) Dalal, Pradeep Kumar; Yadav, Sunita
With a view to explore the potential of pollen load trapping as subsidiary occupation among Indian beekeepers, the present investigations were carried out in 3 seasons (mustard bloom at Hisar and Kaul; multi-floral season at Kaul) during 2016-17 and 2017-18 to determine the optimum pollen trapping frequency that allow economically viable pollen collection as well as sufficient honey production and colony development. Fifteen colonies each of high (12-frame) and medium strength (8-frame) were put to five pollen trapping frequencies viz. daily, alternate days, 3 days, weekly and without trapping (control). The floral biology of dominant flowering crop under different seasons revealed that each flower of mustard, Brassica campestris and Egyptian clover, Trifolium alexandrium offered floral resources to A. mellifera bees for a period of 3 and 3.9 days, respectively. Mean pollen collection from high and medium strength colonies was 14.9 and 8.1 g/colony/day, translating to 1.98 and 1.09 kg/colony, respectively in mustard season. Pollen collection increased with increasing order of trapping frequencies. Pollen collection from high strength colonies from mustard was more in daily pollen trapping (25.3 g/colony/day) followed by alternate (18.4 g), 3 days (17.1) and weekly trapped colonies (14.0 g/colony/day). Similar trend was noticed for medium strength colonies on mustard bloom and multi-floral season, indicating direct relationship of pollen trapping with pollen load collection. Botanical diversity of pollen loads was estimated by employing 3 methods viz. visual, segregation on colour basis and haemocytometer method. Melissopalynological analysis identified 11 pollen types, yellow coloured B. campestris pollen being major source both at Hisar and Kaul comprising >50% of total pollen loads. During multi-floral season (Mar-Apr), white coloured pollen loads from weed, Ageratum conyzoides were in majority during initial phase and T. alexandrium in final phase. Crude protein and calorific value of B. campestris was 24.3% and 367.1 Kcal/100 g while values for A. conyzoides and T. alexandrium were 16.0 and 23.8% and 422.6 and 418.9 Kcal/100 g, respectively. Impact of different pollen trapping frequencies was studied on colony traits viz. honey, nectar, and pollen store, brood area, drone numbers, etc. During mustard bloom, in daily trapping the honey area depleted in high strength colonies (-5.0%) while in medium strength grew by 43.0%. Alternate trapping of high strength and 3 days trapping of medium strength colonies allowed honey area to expand by 95.3 and 73.1%, respectively over season. During multi-floral season, honey area dipped uniformly irrespective of trapping frequencies. Brood development suffered as a result of daily pollen trapping during mustard bloom as high and medium strength expanded by -2.9 and 11.0%. Under alternate trapping of high and 3 days trapping medium strength colony the brood area grew by 22.5 and 49.6%, respectively. During multi-floral season, shortage of good quality major floral source, led to reduction in total brood area across all trapping frequencies. Daily trapping of high strength colonies led to depletion of pollen store area (-24.7%) in colonies which triggered them to additionally recruit maximum proportion of foragers (29.0%) for pollen collection from existing foraging force, impacting other colony functions. Similarly medium strength daily trapped colony recruited additional pollen foraging force of 25.6%. Experimental colonies were also categorized based on pollen hoarding behavior and their sensitivity to hygiene. A total of 14 colonies possessed high pollen hoarding behaviour out of 90 colonies tested during all the season. Moderately sensitive (MS) trait alongside high pollen hoarding character was found in only one of the total lot of colonies. Overall analysis including economics suggested alternate trapping of high strength colonies as more remunerative in comparison to other trapping frequencies with adequate pollen yield, optimum colony growth and honey production with additional economic returns of Rs 264.9 per colony. Among medium strength colonies, 3 days pollen trapping was relatively better with net income of Rs 4.9 as per colony in addition to prolific honey production and brood development.
Open Access
Studies on molecular variability in whitefly, Bemisia tabaci (Gennadius) population in cotton and its management
(CCSHAU, Hisar, 2019-06) Roomi Devi; Yogesh Kumar
The present investigation was carried out at CCS Haryana Agricultural University, Hisar during Kharif seasons of 2017 and 2018. A survey of cotton growing areas was done in north region of India viz. Haryana, Punjab and Rajasthan and whitefly samples were collected to find out the molecular variation among whitefly. MtCOI gene specific primers were used to amplify the mtCOI gene segment of extracted DNA of whitefly. Screening of forty cotton genotypes were done against whitefly and level of resistance was further correlated with different biochemical and morphological traits. Different crops like sorghum, bajra, pigeon pea, cowpea and sesame were grown as intercrops with cotton to know their effects on whitefly population. Efficacy of different pesticides were tested against whitefly. For this two spray were done at ETL and data was recorded before spray and 1st, 3rd, 7th and 10th DAS. Results revealed that in all the samples mtCOI gene segment were amplified at 1000bp band. Sequences were generated from these samples and aligned along with reference sequences all over the world representing seven different clades of B.tabaci to analyse phylogenetic relationship. It was found that our sequences belong to Asia II-1 and clustered in clade of representing Asia II-1 biotype from Northern region of India. During both the years population of whitefly commenced in month of June (24th SMW) and continued till harvest of crop (41st SMW) with two peaks. Observations during Kharif 2017, 2018 and pooled analysis of both the years showed that maximum population was recorded in ARBH 1601 (15.81, 9.76, 12.79 adults/leaf) and minimum in HS 286 (10.03, 5.21, 7.62 adults/leaf), respectively. Whitefly population showed significant negative correlation with maximum temperature and significant positive with morning relative humidity. Population of whitefly showed significant and positive correlation with total sugar content, trichomes density while non significant and positive with protein and chlorophyll content. Significant and negative correlation with phenol, tannin and leaf thickness. Intercropping system revealed significant suppression in all the intercropped treatments over the sole cotton crop. Pooled mean of both the years revealed that minimum population was recorded in cotton intercropped sorghum (3.69 adults/leaf) and maximum in sole cotton (10.82 adults/leaf). Pooled mean of both the years 2017 and 2018 showed that the flonicamid 50% WG @ 150 g/ha (68.65%) was the most effective insecticide while Verticilium lecanii 1.15WP @ 2.5kg/ha (41.11%) was least effective.
Open Access
Varietal preference and eco-friendly management of major insect-pests of maize during storage
(CCSHAU, Hisar, 2020-06) Tiwari, Sangeeta; Yadav, Sunita
Studies on Varietal preference and eco-friendly management of major insect-pests of maize during storage were carried out during 2017-19, in the Department of Entomology CCS HAU, Hisar. The study was based on evaluation of 15 maize genotypes against S. oryzae, R. dominica and T. granarium, evaluation of biochemical losses in various maize genotypes due to infestation by these insect-pests and to test efficacy of different seed protectants against major insect-pests of stored maize. The experimental results revealed that maximum pooled mean susceptibility index of 5.0, 4.7 and 4.7 was recorded for S. oryzae, R. dominica and T. granarium, respectively, in sweet corn therefore, it was categorized as moderately resistant genotype while minimum pooled mean susceptibility index of 1.6, 2.1 and 1.6 was recorded for HKi 161 so, it was categorized as resistant genotype. HKi 161 was found to be resistant to S. oryzae with minimum (8.67) pooled mean percent grain damage while HQPM 1 was found resistant for R. dominica and T. granarium with minimum pooled mean percent grain damage of 13.88 and 11.00, respectively. The minimum pooled mean percent weight loss of 8.26 and 7.58 was recorded in HQPM 1 against S. oryzae and R. dominica respectively while for T. granarium minimum (12.85) pooled mean percent weight loss was recorded in HKi 161. The biochemical parameters viz phenol, total soluble sugar, ash, moisture and protein were analysed in uninfested and infested seeds of various maize genotypes. The phenol, ash and protein showed reduction as the infestation intervals increases while moisture and total soluble sugar showed increase as the infestation intervals increases. In samples infested with S. oryzae, R. dominica and T. granarium, susceptibility index showed negative correlation with phenol (-0.79, -0.72, -0.71), positive correlation with TSS (0.84, 0.81, 0.83), moisture content (0.87,0.63,0.69) and protein content (0.29,0.65,0.24), respectively while percent grain damage showed negative correlation with phenol (-0.86, -0.74, -0.57), positive correlation with TSS (0.71, 0.71, 0.74) , moisture (0.84,0.66,0.56) and positive correlation with protein (0.30, 0.31 , 0.21), respectively. After infestation, percent weight loss showed negative correlation with phenol (-0.74, -0.69,- 0.65) while positive with TSS ( 0.64, 0.68, 0.80), moisture (0.74, 0.44, 0.69) and protein (0..31, 0.38, 0.13). Bioefficacy of various seed protectants against S. oryzae, R. dominica and T. granarium revealed that neem oil @ 15ml/kg seed was significantly superior over rest of the treatments with highest pooled mean percent adult mortality of 94.76, 91.90 and 92.83, respectively. It was most ecofriendly treatment with minimum pooled mean S. oryzae adult population growth of 12.54 and pooled mean T. granarium larval population growth of 77.57 whereas for R. dominica, cannola oil @ 20 ml/kg seed found most effective with minimum (12.44) pooled mean adult population growth. The neem oil, eucalyptus oil and cannola oil showed zero per cent pooled mean grain damage for S. oryzae, R. dominicaand T. granarium. The repellency activity revealed that neem oil showed maximum (80 %, 80 % and 86.67 %) mean repellence against S. oryzae, R. dominica and T. granarium, respectively which was followed by eucalyptus oil. The maximum (96%) germination was recorded for eucalyptus leaves followed by fly ash & control (92% each), turmeric powder (90%), neem oil and silica gel (86% each), eucalyptus oil & paddy husk (84% each), paddy husk ash (80%) and canola oil (74%). The boric acid showed adverse effect on germination of maize seeds.
Open Access
Pollination efficiency of Apis mellifera L. colony placement modes under protective environment and field conditions
(CCSHAU, Hisar, 2019-05) Rinku; Chaudhary, O.P.
The present research was conducted at department of Vegetable Science (bitter gourd, IPNH) and Horticulture (strawberry, NVPH), CCS Haryana Agricultural University, Hisar. Four honey bee colony placement modes viz. i) bee colony permanently inside enclosure, ii) colony inside enclosure with dual entrance, iii) colony inside enclosure on alternate days, and iv) colony replacement after weakening were further evaluated with three other treatments namely hand pollination (HP), without bee pollination (WBP) and crop grown in open field conditions (open pollination, OP) for two commercial crops, one vegetable- bitter gourd (under insect proof net house) and a fruit- strawberry (under naturally ventilated poly house) for two crop seasons. A. mellifera pollination units comprised of 3-frame colony that were introduced at the initiation of flowering in enclosures. In bitter gourd conditions under enclosures prompted early flowering (30-31 days) and prolonged flowering (88-89 days) compared to crop in open pollination (40 days, spread over 76 days). Hymenopterans (63.35%) dominated with four Apis honey bees (26.49%) and individually A. mellifera visiting from nearby apiary was most dominant (14.42%) while six non Apis hymonopterans comprised of 36.88% of all floral visitors. A. mellifera foragers in exhibited higher foraging rate as they visited higher number of flowers (5.3-7.1 min-1) compared to open field conditions (4.0 min-1). A pistillate flower produced 4.12 fold higher DNS (0.907 mg/flower) than staminate flower (0.221 mg/flower). Superior fruit quality was obtained in terms of length, breadth, volume, weight, TSS, acidity of fruits in treatments under enclosures supplemented with honey bee colonies as compared to open field conditions. Maximum yield was obtained in treatments under enclosures ranged from 19783.14-33816.33 kg/hac while remarkable lower yield in WBP (4033.29 kg/ha), open pollination (8849.91 kg/ha) and hand pollination (17549.82 kg/ha). Colony with dual entrance and colony permanently inside the encloure treatments are recommended as they fulfil the dual aim of optimum pollination under the enclosures as well as strong colony growth during the entire period of flowering. In strawberry with total flowering period of 78-89 days visited by a total of 17 floral visitors dominated by Hymenoptera (71.13%) comprising of four Apis bees (45.81%) and six individual non-Apis bees (25.32%). Foraging rate of A. mellifera was higher inside enclosures (5.3-5.8 min-1) compared to open field conditions (3.3 min-1). The mature 3 day old flowers (DOF) produced maximum DNS (5.503 mg/flower) and lower amounts were produced in 4 (3.961 mg), 2 (3.826 mg) and 1 DOF (2.697 mg/flower). Maximum DNS was produced by strawberry flowers grown under open field conditions (4.279 mg/flower) than under enclosures (3.922-3.981 mg/flower). Maximum fruit yield were obtained when bee colony was kept permanently inside enclosure (0.727 kg/picking, 18.18 kg/plot and 0.606 kg/plant) followed by colony dual entrance (0.697 kg/picking, 17.43 kg/plot and 0.606 kg/plant) while in absence of pollination, minimum yields per picking (0.343 kg), plot wise (8.58 kg) as well as per plant basis (0.286 kg). Quantitative yield increase was matched by corresponding increase in quality traits of fruit dimension, volume, weight, achene numbers, TSS, acidity, ascorbic acid and anthocynin content in different pollination treatments. Colony with dual entrance and colony permanently inside the enclosure treatment with higher quantitative and qualitative yields and strong colony strength likely ensure optimum pollination of strawberry fruits during the long flowering season under enclosures
Open Access
Role of insect pollinators towards yield attributing parameters of castor (Ricinus communis Linnaeus)
(CCSHAU, Hisar, 2020) Nayak, Sudhanshu Bala; Yogesh Kumar
The present investigation entitled “Role of insect pollinators towards yield attributing parameters of castor (Ricinus communis Linnaeus)” was carried out at Research Farm and Apicultural laboratory, Department of Entomology, CCS Haryana Agricultural University, Hisar on the two promising hybrids, GCH-7 and DCH-177 during Kharif of 2018 and 2019. A total of 36 insect species belonging to nineteen families of six different orders were recorded from the R. communis flowers. Among them, Hymenopterans occupied the dominant share (50%) followed by Lepidopteran (25%), Dipteran (11%), Coleopteran (8%), Hemipteran (3%) and Orthopteran (3%). Among them, 12 species were reported to be frequent visitors where as A. florea was the most abundant species followed by A. cerana, A. mellifera, and A. dorsata with abundance of 12.41, 4.73, 2.83 and 1.64 bees/m²/5min and the least abundant was Eristalinus sp. (0.28 bees/m²/5min) respectively. Hymenopterans were dominated as flower visitors of R. communis accounting 97.54 per cent of the total pollinators. Among them, four social bee species viz., A. florea (49.17%), A. cerana (18.76%), A. mellifera (11.21%) and A. dorsata (6.49%) were considered to be principal pollinators of castor. Insect visitors had followed the unimodal diurnal activity pattern with single visiting peak at 1000-1200 hours.With pertaining to duration of foraging, A. mellifera had highest working duration i.e. 10:39 hours: minutes .The foraging rate was found to be maximum in A. dorsata (6.79) followed by A. mellifera (6.03), A. cerana (5.39) and A. florea (5.07) Further, the lowest number of flowers was visited by Eristalnus sp. (2.33 flowers/minute). The foraging speed was recorded highest for A. cerana (6.26) followed by A. mellifera (5.12), A. dorsata (4.20), A. florea (3.74) lowest foraging speed was recorded for X. iridipennis (2.67 seconds/flower). While computing pollination index, the high pollination efficiency of social honey bees over the solitary bees was noticed. The average dry nectar sugar varied from 0.035 to 0.091 mg/flower and significantly the peak production were recorded during 1000-1200 hours. Effect of different modes of pollination on on qualitative and quantitative yield parameters of castor showed that the capsule setting (%), number of capsules per plant, total number of seeds per plant, 100 seeds weight, seed yield per plant, seed yield per hectare, seed germination (%), seed vigour I and II and oil content (%) were highest in case of open pollination (OP) as compare to bee pollination (BP) and without insect pollination treatment (WIP).

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