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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
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 sesame (Sesamum indicum Linnaeus)
(CCSHAU, Hisar, 2019) Rao, Kavadana Sankara; Yogesh Kumar
The present investigation entitled “Role of insect pollinators towards yield attributing parameters of Sesame (Sesamum indicum Linnaeus)” was carried out at Research farm and Apicultural laboratory, Department of Entomology, CCS Haryana Agricultural University, Hisar on the two promising cultivars, HT-1 and HT-2 during Kharif of 2017 and 2018. Flowers of the both cultivars had the similar floral biology in relation to different floral parts which essentially consisted of five sectioned calyx (5-6 mm), five lobed corolla (26-36 × 10-23 mm), two pairs of stamens, gynoecioum with superior ovary (3-7 mm) and characteristic extrafloral nectaries at base of pedicel. Flowers were found to be visited by a total of 34 insect species belonging to four orders and 18 families. Hymenpoterans occupied the dominant share (62 %) followed by lepidopterans (17 %), dipterans (12 %) and coleopterans (9%). Among them, 17 species were reported to be frequent visitors where A. dorsata was the abundant species with an abundance of 4.76, bees/ m²/5 min (26.92 %) and it was followed by A. mellifera, M. lanata and A. florea with abundance of 2.34 (13.20 %), 2.23 (12.58 %) and 1.32 (7.44 %) bees/m²/5 minute, respectively, whereas Coelioxys sp., A. cingulata, Compsomeriella sp., and X. iridipennis were found be the least abundant species. Insect visitors/ pollinators had followed the unimodal diurnal activity pattern with single visiting peak at 1000 -1200 hours. With pertaining to foraging behaviour, A. dorsata had highest working duration (11.09 hours) and it was followed by A. mellifera, A. cerana, M .lanata and M. cephalotes. The overall mean foraging rate was found to be maximum in M. cephalotes (5.65 flowers/ minute) and M. lanata (5.54 flowers /minute) than other recorded species, meanwhile the foraging speed was recorded highest for C. smaragdula (11.84 seconds/ flower) and A. florea (8.43 seconds/flower). The pollination index computed revealed the high pollination efficiency of social honey bees over the solitary bees. The average dry nectar sugar present in a single flower varied from 0. 205 to 0.542 mg and significantly the peak production were recorded at 1000 - 1200 hours. Both varieties profoundly responded to different modes of pollination, where significant improvement of various qualitative and quantitative yield traits of S. indicum registered in bee pollination treatments than open pollination and without insect pollination treatments. The present study also proved the utility of sesame as resource crop for beekeeping.
Open Access
Population dynamics and management of major insect-pests on cabbage
(CCSHAU, 2019) Purti; Rolania, Krishna
The present studies on population dynamics and management of insect-pests on cabbage were conducted at Experimental Area, Department of Entomology, CCS Haryana agricultural University, Hisar during 2017-18 and 2018-19. The population dynamics studies of major insect-pests revealed that the peak population of diamondback moth (Plutella xylostella), semilooper (Trichoplusia ni) and aphid (Brevicoryne brassicae) was observed in 11th and 12th SMW (Standard Meteorological Weeks) last week of March, 2017-18 and 2018-19 whereas, the peak population of cabbage butterfly (Pieris brassicae) was observed in 13th SMW i.e., first week of April in both the years. The correlation studies revealed that the population of diamondback moth, semilooper and aphid had a positive and significant correlation with maximum and minimum temperature and negative but significant correlation with morning and evening relative humidity during 2017-18. In 2018-19 the population of diamondback moth and aphid had a positive and significant correlation with maximum temperature and sunshine hours and negative but significant correlation with evening RH in both the years. Population of semilooper showed the positive and significant correlation with temperature (both maximum and minimum) and sunshine hours and negative but significant correlation with relative humidity (both morning and evening) in both the years. Coccinellids, syrphid fly and spiders were recorded as natural enemies along with the population of insect-pests. Peak incidence of natural enemies was recorded in 12th and 13th SMW i.e., last week of March and 1st week of April. The efficacy studies of insecticides showed that the lowest population of diamondback moth, semilooper and cabbage butterfly was observed in chlorantraniliprole 18.5 SC @ 50 ml and the highest population of these pests was observed in nimbecidine 0.03 EC during both the years. While in the case of aphids malathion 50 EC proved to be the best insecticide and Bacillus thuringiensis was proved to be the least effective insecticides in reducing the population of pest in both the years. The cumulative effect of all the treatments indicated that the maximum yield was recorded in chlorantraniliprole 18.5 SC @ 50 ml i.e., 194.70 q/ha (pooled) and the lowest in nimbecidine 0.03 EC i.e., 157.70 q/ha (pooled). The IPM modules studies revealed that module M2 was proved to be the effective module against diamonback moth, semilooper and cabbage butterfly during both the years with 3.41, 1.01 and 17.18 larvae/plant, respectively followed by module M3 which recorded 3.51, 1.13 and 18.74, respectively. Module M1 proved to be the least effective module (4.10, 1.24 and 19.14 larvae/plant, respectively) but superior over control. In case of aphid, module M3 was the most effective module followed by module M1 (11.59 aphids/plant). Module M2 (11.91 aphids/plant) proved to be the least effective module but effective over control. The cumulative effect of two years data revealed that the maximum yield was recorded in module M2 (198.90 q/ha) statistically at par with module M3 (191.64 q/ha) and the lowest yield was recorded in module M1 (183.14 q/ha). The residues of chlorantraniliprole 18.5 SC (50 ml and 100 ml/ha) and malathion 50 EC (1 L and 2 L/ha) were determined at different intervals i.e., 0 (1 hr), 3, 5, 7, 10 and 15 days after application of insecticides. Chlorantraniliprole 18.5 SC was dissipated faster than malathion 50 EC. The residue level of malathion was found below MRL (Maximum Residue Limit) i.e., 3.0 mg kg-1on 0 day at single and double dose whereas, the residue level of chlorantraniliprole was found below MRL i.e., 0.03 mg kg-1 after 7th day at single dose and after 10th day at double dose.
Open Access
Effect of biorationals and weeding on management of whitefly (Bemisia tabaci) in cotton
(CCSHAU, 2019) Amit; Dalip Kumar
The present study was carried out during Kharif 2018 at Biocontrol Laboratory and Research Farm, Cotton Research Station, Sirsa. Mean adult population (adults/leaf) peaked twice during the study i.e. in 29th (8.01 and 8.82/ leaf) and 35th SMW (8.96 and 10.89 / leaf) whereas, whitefly nymphs peaked in 34th SMW (20.12 and 23.21/leaf) in non-weedy and weedy habitat respectively. White fly population (nymphs and adult) had a non-significant positive correlation with temperature and relative humidity. Adult population in non-weedy habitat was significantly negatively correlated with rainfall (r = -0.502) and wind speed (r = -0.515) whereas nymphal population showed non-significant negative correlation. Regression analysis revealed that influence of weather parameters was high and significant on whitefly adults (R2=0.86) and nymphal (R2=0.57) population. Maximum mortality of adults and nymphs (among biorationals) after 1st spray in non-weedy (66.76 and 60.65 per cent mean mortality in adult and nymphal population, respectively) as well as weedy habitat (56.77 and 55.54 per cent mean mortality in adult and nymphal population, respectively) was observerd in nimbicidine 300 ppm treatment. Efficacy Nimbicidine 300 ppm on whitefly adults was followed by Verticillium lecanii, Beauveria bassiana and Metarhizium anisopliae and after 2nd spray the same trend was observed. Among the entomopathogenic fungi, V. lecanii was found more effective against whitefly adults whereas M. anisopliae caused higher mortality in nymphal population. Parasitisation of whitefly nymphs by aphelenid wasp, Encarsia spp. ranged from 2.63 to 28.51 per cent in non-weedy habitat and from 3.85 to 35.75 per cent in weedy habitat and peak parasitization was observed in 41st SMW in both habitats. Parasitization showed non-significant negative and positive correlation with temperature and relative humidity, respectively. Parasitization was at weak correlation with rainfall. Weather parameters cumulatively caused 74.0 and 66.0 per cent change in nymphal parasitization in non-weedy and weedy habitats, respectively. All biorationals were found safe for Encarsia sp. Parasitization, however V. lecanii showed highest and Nimbecidine 300 ppm lowest mean parasitisation after both spray. Highest cotton yield (kg/acre) among the biorationals in weedy as well as non-weedy, was obtained with Nimbecidine 300 ppm treatment (768.26 and 642.00 kg/ acre in weedy and non-weedy habitat respectively) followed by V. lecanii (741.02 and 621.28 kg/acre) lowest yield was obtained in control plots (603.16 and 536.24 kg/acre).
Open Access
Nectar secretion rhythms and foraging behaviour of honey bees in early sown rapeseed-mustard genotypes
(CCSHAU, 2019) Poonam; Yadav, S.S.
The present study was carried out on six early sown genotypes of rapeseed-mustard at Research Area of Oilseeds Section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar during 2018. A total of 17 insect species visited flowers of early sown genotypes viz., 9 Hymenopterans, 3 Dipterans, 4 Lepidopterans, and 1 Coleopteran. The abundance (bees/m2/5 min) of A. florea was highest (8.5) followed by A. mellifera (3.9), A. dorsata (3.6) and A. cerana (3.1). Abundance of bee species was maximum (5.6 bees/m2/5 min) in genotypes TH 68 and SANGAM. A. cerana foraged maximum number of flowers per minute (18.20) followed by A. dorsata (17.57), A. mellifera (17.32) and A. florea (6.45). Foraging rate (flowers/min) of all bee species was maximum (14.98 and 14.90) in genotypes TH 68 and SANGAM. Time spent per flower (sec) was maximum (5.3) by A. florea followed by A. dorsata (1.7), A. mellifera (1.6) and A. cerana indica (1.3). The maximum time spent per flower by all bee species (2.6) was in genotype PDZ 9. Nectar or pollen gatherers were maximum in A. dorsata (37.8% and 25.6%, respectively), while both nectar and pollen gatherers were maximum in A. cerana (45.3%). Nectar foraging, pollen foraging and both nectar and pollen foraging was maximum at peak flowering (36.0%), peak flowering (23.8%) and flowering cessation (42.9%), respectively. Out of the total foragers, top workers were maximum in A. dorsata (97.8%), while side workers were maximum in A. florea (41.0%). Based on flowering phenology, TH 68 genotype was the earliest (33.7 and 85.3 DAS) while RH 725 was the latest (39.7 and 91.7 DAS) to initiate and cease flowering. The flower morphological parameters of different genotypes i.e. mean flower length and breadth varied from 1.40-1.53 cm and 1.61-1.79 cm respectively, flower color was bright yellow, corolla and calyx length ranged from 0.84-0.88 cm and 0.56-0.61 cm respectively, ovary dimensions (length and breadth) were in the range 3.68-3.76 and 2.14-2.18 mm in different genotypes. Mean amount of Dry Nectar Sugar varied from 0.77-0.82 mg, 0.79- 85 mg and 0.61-0.69 mg per flower at flowering initiation, peak and cessation respectively and the genotypes TH 68 and SANGAM were consistently superior nectar-sugar producers throughout the study. Total Soluble Solids of flower nectar (or total sugar content in %) varied from 14.8 % to 38.2 %. The energy reward in studied genotypes varied from 12.9-13.7, 13.2-14.3 and 10.2-11.5 joules per flower during flowering initiation, peak and cessation respectively.
Open Access
Biology, population dynamics and management of Tobacco caterpillar (Spodoptera litura Fabricius) on Castor
(CCSHAU, 2019) Deepak; Yadav, Satyapal
The Present studies entitled “Biology, population dynamics and management of Tobacco caterpillar (Spodoptera litura, Fabricius) on Castor” were carried out during Kharif, 2018. Biology of the S. litura was studied in laboratory of Department of Entomology, Chaudhary Charan Singh Haryana Agricultural University, Hisar. Total life cycle of S. litura varied from 21 to 37 days with an average period of 34.85 ± 3.44 days with a male-female ratio of 1:1.4 and adult emergence percentage was 86.66 per cent. Population dynamics of the insect pests and management of S. litura was carried out at the research farm of the Regional Research Station, Bawal. Castor semilooper was first observed during second week of August and continued to infest castor crop up to mid of October with a peak population of 6.0 larvae per plant during last week of August. The incidence of S. litura started during first week of September and continued up to first week of November with peak population level of 3.4 larvae per plant during second week of October. The infestation of D. punctiferalis initiated from third week of October and last till second week of March with a peak infestation of 12.20 per cent during second week of December. The infestation of capsule borer was positively significantly correlated with maximum temperature and showed highly positive significant correlation with maximum temperature (r = 0.775**). The attack of E. flaviscens started from second week of October to third week of February with a peak population 16.2 nymph/3 leaves/plant during first week of November. The incidence of E. flavescens showed highly positive significant correlation with maximum temperature (r = 0.913 **). Experiment on management of S. litura was conducted at RRS, Bawal and revealed that after first spray it was observed that among all the treatments standard check (Quinalphos 300g a.i. per ha) was most effective against S. litura while among bio-pesticides NPV- Sl 350 LE/ha was most effective and at par with treatment Bt var. kurstaki @2kg/ha. The least effective treatment was Neem oil 5% (crude oil) followed at par by NSKE 5 %.
Open Access
Ecofriendly management and screening of mungbean (Vigna radiata L.) genotypes against whitefly (Bemisia tabaci Gennadius)
(CCSHAU, 2019) Khin Thanda Min; Verma, Tarun
Field studies on “Ecofriendly management and screening of mungbean, Vigna radiata L. genotypes against whitefly Bemisia tabaci Gennadius” was carried out during the Kharif, 2018. The minimum and maximum population of whitefly nymph observed in MH 318 and MH 1315 (2.20, 11.68 whitefly nymph /3 leaves/plant) respectively. The minimum and maximum populations of whitefly adults were observed on genotype MH 318 and MH 1413 (13.65, 32.98 whitefly/plant), respectively. The activity of whitefly nymphs and adults reached its peaks at 35DAS (32th SMW means 2nd week of August). Maximum grain yield was obtained in genotype MH 1467 (575.0 kg/ha) and lowest yield was observed in genotype Basanti (152.78 kg/ha). Correlation of whitefly with the maximum, minimum temperature and sunshine hours was positive and significant, while negative and non-significant with evening relative humidity in different genotypes screened. Biorational spray on variety MH 421 was done which indicated minimum whitefly adult population in Neem oil 2% (crude) (T4) in first spray. However, during second spray minimum whitefly adult (7.00 whitefly adults/plant) were recorded in T2 (NSKE 5% aqueous extract). Neem oil 2% (crude) (T4) was found most effective (12.38 whitefly adults/plant) treatment on the basis of overall mean of first and second spray. Maximum grain yield (259.26 kg/ha) was obtained in T1 (NSKE 5% Methanolic extract) which was at par with T2 NSKE 5% (Aqueous extract): (217.41kg/ha) andT4 Neem oil 2% (crude): (221.11 kg/ha). Correlation between whitefly and weather factors was exhibited significantly positive with maximum temperature (r=0.843), negative correlated with relative humidity (r =-743) and rainfall (r=-747). The populations of tobacco caterpillar were significantly positive correlated with the minimum temperature (r=0.810) and negatively correlated with the relative humidity(r=-0.275). Correlation between maximum temperature, minimum temperature with spotted pod borer was found positive (r= 0.445, 0.207), while it was negative with the relative humidity and rainfall (r= -0.336, -0.471) (r= - 0.269) respectively.

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