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This study is on the nutritional efficiency of the host plants viz., Corchorus olitorius, C. capsularis, Hibiscus cannabinus, H. sabdariffa, Crotoloria juncea and Boemheria nivea and their biochemical influences on Bihar hairy caterpillar Spilosoma obliqua (Walker) (Lepidoptera: Arctiidae). The results revealed that the nutritional and biochemical parameters varied significantly with the infested and uninfested host plants. The growth rate of 5th instar larvae varied from 13.06 mg/ day in B. nivea to 17.90 mg/ day in C. olitorius; it was 14.80 ± 0.69, 16.74 ± 0.74, 14.94 ± 0.29 and 15.06 ± 0.26 mg/ day on C. capsularis, H. cannabinus, H. sabdariffa, C. juncea and B. nivea, respectively. Thus, C. olitorius appeared to be the most suitable food source for growth and development of S. obliqua. Peroxidase and polyphenol oxidase were elicited by the infestation of S. obliqua indicating their role in insect defence. Higher phenol and peroxidase content in the host plants adversely affected the food utilization indices. This is the possible explanation for variation in food consumption and development of S. obliqua; and it might be due to significant differences in the biochemical contents of the evaluated bast fibre crops.

Whitefly is an important pest and vector of many plant begomoviruses. Investigations were carried out to understand the acquisition, retention, transmission, and gender basis transmission efficiency of Mesta yellow vein mosaic virus (MeYVMV) by whitefly. The minimum acquisition access feeding period (AAFP) was 0.10 h which resulted in 11.1% infected plants. Based on LAMP assay and yellowing symptoms, 100% virus acquisition was achieved by whitefly with an exposure of 18 to 48 h. Virus was transmitted in tested plants up to 88.8% after 1 to 10 days retention time of viruliferous whiteflies, whereas no symptoms were observed after 35 days. Fifteen minutes of exposure to viruliferous whiteflies on healthy plants resulted in 11.1% transmission. Cent percent transmission of virus was achieved in plants with 12 h exposure period. Highest virus transmission efficiency of 55.60% was observed in female whitefly compared to 33.3% in single male whitefly. Present study shall help to understand the interaction of insect-plant–virus relationship, epidemiological knowledge, and formulation of management strategies against virus and its vector.

Yellow mite is a serious pest of many field and horticultural crops including jute. As repeated use of acaricides possess problem of resistance, alternatively, the infectivity of talc based formulation of three entomopathogens, i.e., Lecanicillium lecanii (Ll), Isaria fumosorosea (= Paecilomyces fumosoroseus ) (Pf) and Beauveria bassiana (Bb) at 4x10 8 cfu/ml, and 6x10 8 cfu/ml concentrations were evaluated against yellow mite under laboratory condition. In both the concentrations, Pf and Bb recorded significantly higher mortality of yellow mite than Ll. At 3-DPT (days post treatment) significantly highest mortality was observed in Pf (30.35%) followed by Bb (21.59%) and Ll (4.87%). Later on at 4 and 5-DPT period the level of mortality in Pf and Bb treated population was at par but significantly higher than Ll. At 5-DPT, Pf recorded maximum cumulative mortality (40.92%) at par with Bb (35.99%) and significantly higher than Ll (12.92%). Significantly higher cumulative mortality at 6x10 8 CFU/l concentration during 5 days after treatment was 34.35%. The infectivity of talc based formulation of Ll at both the concentrations was significantly less than Pf and Bb. Higher infectivity of I. fumosorosea indicates it to be ideal for yellow mite control in jute.

The fungal entomopathogen Beauveria bassiana is a promising biocontrol agent for many pests. Some B. bassiana strains have been found effective against jute pests. To monitor the survival of field released B. bassiana a rapid and efficient detection technique is essential. Conventional methods such as plating method or direct culture method which are based on cultivation on selective media followed by microscopy are time consuming and not so sensitive. PCR based methods are rapid, sensitive and reliable. A single primer PCR may fail to amplify some of the strains. However, multiplex PCR increases the possibility of detection as it uses multiple primers. Therefore, in the present investigation a multiplex PCR protocol was developed by multiplexing three primers SCA 14, SCA 15 and SCB 9 to detect field released B. bassiana strains from soil as well as foliage of jute field. Using our multiplex PCR protocol all the five B. bassiana strains could be detected from soil and three strains viz., ITCC 6063, ITCC 4563 and ITCC 4796 could be detected even from the crop foliage after 45 days of spray.

survey for weed killers in jute-based crop ecosystem was conducted at the research farm of ICAR-CRIJAF, Barrackpore during 2018 and 2019 cropping season. The nutgrass weevil, Athesapeuta cyperi caused 46.67 – 85.00% dead heart in Cyperus rotundus in the jute ecosystem. This is the first report of A. cyperi on nutgrass in the jute ecosystem in West Bengal. This study throws a hope of using this weevil as a potential biocontrol agent against the most notorious weed the nut grass, which has been gradually developing resistance against many of the commonly used herbicides.

Surveys were conducted in intensive jute growing areas of West Bengal to collect information on natural enemies and other entomopathogens infecting jute hairy caterpillar Spilosoma obliqua (Lepidoptera: Arctiidae). The jute crop supports large number natural enemies of S. obliqua and entomopathogens. Among the braconid larval parasitoids, Meteorus spilosomae (Hymenoptera: Braconidae) and Protapantales obliquae (Hymenoptera: Braconidae) were the key mortality factors. The activity of these parasitoids was noticed from mid- May to mid-July during the cropping season. The parasitoid, P. obliquae is a gregarious, endoparasitoid specific to S. obliqua and parasitize to the extent of 38% up to third instar of larvae whereas M. spilosomae reported to cause up to 77% of parasitisation on S. obliqua under field condition. Bacillus thuringiensis and nuclear polyhedrosis virus were found be very effective with mortality of, 64 and 93% respectively. These parasitoids and pathogens can be used as potential bio-control agents against jute hairy caterpillar through conservation, augmentation and mass multiplication.

Lantana camara is a common weed species in tropics and sub tropics and coastal locations of Asia. The fumigant toxicity of essential oil extracted from leaves of plant was tested against almond mot...

In vitro study was conducted to test mycellial growth inhibition effect of plant extracts on Macrophomina phaseolina causing stem rot of jute as well as for feeding inhibition and mortality on 3rd instar larvae of Bihar hairy caterpillar, Spilosoma obliqua Walker. The result revealed, at 2000 ppm, acetone extracts of sunnhemp and Azeratum conyzoides exhibited maximum of 34.44% and 41.85% mycellial growth inhibition respectively. Whereas, 83.32% and 66.67% spore germination inhibition of the fungus was observed respectively. At 5000 ppm, methanolic extracts of Crotolaria quinquefolia, garlic, curry leaf and turmeric oil recorded 35.55%, 44.44%, 50.00% and 70.00% mycellial growth inhibition of the fungus. Methanolic extracts of C. juncea, C. quinquefolia, curry leaf and garlic recorded above 80.00% feeding inhibition on S. obliqua and larval mortality of 20.00%-44.44%. It is clear that neem, sunnhemp, garlic and turmeric extract possess antifungal, insecticidal, antifeedant properties and may be integrated for management of stem rot as well as S. obliqua in jute crop.

We studied the life cycle of the broad mite, Polyphagotarsonemus latus (Banks) (Prostigmata: Tarsonemidae), on 2 cultivated jute species (Corchorus olitorius L. and Corchorus capsularis L.; Malvales: Malvaceae) and 5 wild species (Corchorus aestuans L., Corchorus pseudo-olitorius Islam & Zaid, Corchorus fascicularis Lamarck, Corchorus tridens L., and Corchorus trilocularis L.) under laboratory conditions. Results showed that the egg incubation period, larval and nymphal durations, and adult male and female longevities of P. latus varied significantly on different jute species. The larval period (mean ± SD) was significantly shorter (57.00 ± 2.07 h) on C. olitorius than on C. fascicularis, C. aestuans, and C. tridens (68.00 ± 1.58 to 72.00 ± 1.30 h). The phenol content was greatest in C. trilocularis (61.92 ± 1.91 μg/g), and it was 16.26 ± 1.34 μg/g and 20.45 ± 1.43 μg/g in C. olitorius and C. capsularis, respectively. The polyphenol oxidase content was smallest in C. capsularis (0.99 ± 0.10 μg/mL...

The oviposition, feeding behavior, and development of the jute hairy caterpillar Spilosoma obliqua Walker (Lepidoptera: Arctiidae) was studied on one cultivated jute species, Corchorus olitorius L. (‘JRO-204') (Malvales: Malvaceae), and 5 wild jute species, viz., C. tridens L., C. trilocularis L., C. pseudo-olitorius Islam & Zaid, C. aestuans L., and C. fascicularis Lamarck under laboratory conditions with a temperature of 27 ± 2 °C and relative humidity of 80 ± 5%. These host plant species had considerable influence on oviposition, larval feeding behavior, larval survival, larval weight, pupation, pupal weight, and adult emergence. Significant differences were observed in oviposition preference based on numbers of eggs laid by the adults. The mean number of egg clusters differed significantly with 3.6 ± 0.3, 3.0 ± 0.6, 3.3 ± 0.3, 3.0 ± 0.6, 1.0 ± 0.6, and 2.0 ± 1.2 on C. olitorius, C. fascicularis, C. trilocularis, C. pseudo-olitorius, C. tridens, and C. aestuans, respectively. The C. pseudo-oli...

Jute (Corchorus sp.) is naturally occurring, biodegradable, lignocellulosic-long, silky, golden shiny fiber producing plant that has great demands globally. Paper and textile industries are interested in jute because of the easy availability, non-toxicity and high yield of cellulosic biomass produced per acre in cultivation. Jute is the major and most industrially used bast fiber-producing crop in the world and it needs protection from insect pest infestation that decreases its yield and quality. Single locus integration of the synthetically fused cry1Ab/Ac gene of Bacillus thuringiensis (Bt) in Corchorus capsularis (JRC 321) by Agrobacterium tumefaciens-mediated shoot tip transformation provided 5 potent Bt jute lines BT1, BT2, BT4, BT7 and BT8. These lines consistently expressed the Cry1Ab/Ac endotoxin ranging from 0.16 to 0.35 ng/mg of leaf, in the following generations (analyzed upto T4). The effect of Cry1Ab/Ac endotoxin was studied against 3 major Lepidopteran pests of jute- semilooper (Anomis sabulifera Guenee), hairy caterpillar (Spilarctia obliqua Walker) and indigo caterpillar (Spodoptera exigua Hubner) by detached leaf and whole plant insect bioassay on greenhouse-grown transgenic plants. Results confirm that larvae feeding on transgenic plants had lower food consumption, body size, body weight and dry weight of excreta compared to non-transgenic controls. Insect mortality range among transgenic feeders was 66–100% for semilooper and hairy caterpillar and 87.50% for indigo caterpillar. Apart from insect resistance, the transgenic plants were at par with control plants in terms of agronomic parameters and fiber quality. Hence, these Bt jutes in the field would survive Lepidopteran pest infestation, minimize harmful pesticide usage and yield good quality fiber.

The fungal entomopathogen Beauveria bassiana is a promising biocontrol agent for many pests. Some B. bassiana strains have been found effective against jute pests. To monitor the survival of field released B. bassiana a rapid and efficient detection technique is essential. Conventional methods such as plating method or direct culture method which are based on cultivation on selective media followed by microscopy are time consuming and not so sensitive. PCR based methods are rapid, sensitive and reliable. A single primer PCR may fail to amplify some of the strains. However, multiplex PCR increases the possibility of detection as it uses multiple primers. Therefore, in the present investigation a multiplex PCR protocol was developed by multiplexing three primers SCA 14, SCA 15 and SCB 9 to detect field released B. bassiana strains from soil as well as foliage of jute field. Using our multiplex PCR protocol all the five B. bassiana strains could be detected from soil and three strains viz., ITCC 6063, ITCC 4563 and ITCC 4796 could be detected even from the crop foliage after 45 days of spray.

Effect of six constant temperatures viz., 18±1, 21±1, 24±1, 27±1, 30±1 and 33±10C was studied on the egg hatchability, larval pupal development and adult survival of Spilarctia obliqua. Development rate of egg, larva and pupa gradually increased with increase in temperature, while total developmental period decreased. Mean developmental period of the pest decreased from 93.73 days at 18±10C to 31.20 at 33±10C. The lowest and the highest temperatures at which no development took place were found to be 12±10C and 39±10C, respectively. Regression equations between development rate and temperature were found to be Y= 0.0189 X -0.1998 (R2=0.88) for egg, Y=0.00122 X -0.0248 (R2=0.84) for small larva (1-3rd instar), Y=0.0058 X -0.0675 (R2=0.76) for large larva (4-6th instar), Y=0.0074 X-0.1075 (R2=0.94) for pupa and Y=0.0142 X-0.4363 (R2=0.79) for adults. Developmental threshold were determined to be 10.57, 11.27, 11.55, 15.28 and 10.92oC for egg, small larva, large larva, pupa, and adult respectively with corresponding thermal constant being 52.91, 344.82, 243.90, 142.85 and 70.42 degree days (DD). Thermal constant to complete a generation was found to be 854.90 DD. This was the first studies on this aspects, these estimated thermal thresholds and degree days could be used to predict the S. obliqua activity in the field for their effective management through pest forecasting.

Field experiment was conducted for disease management with seven eco-friendly treatments in Corchorus olitorius jute during 2012-2013 under randomized block design (RBD) in three replications with variety JRO-524. The ecofriendly treatment 50% N: P: K + seed treatments with Azotobacter and phosphorus solubilizing bacteria (PSB) @ 5g/Kg+ Trichoderma viride (seed treatment @ 5g/Kg of seed and soil application @ 2Kg/ha at 21DAS) + Psuedomonas fluorescens spray @ 0.2% at 45DAS was found superior with minimum per cent disease incidence (3.46 and 1.43%) as compared to control (13.17 and 4.96%). The second best treatment was found with Farm yard manure (FYM) @ 5t/ha + seed treatment with Azotobecter and PSB @ 5g/Kg+ T. viride (seed treatment @ 5g/Kg of seed and soil application @ 2Kg/ha 21DAS)+ P. fluorescencs spray @ 0.2% at 45DAS and showed 3.61 and 2.0% disease incidence. The treatment with N: P: K @ 60:30:30 and seed treatment with carbendazim 50WP @ 2g/Kg at 45DAS showed 4.56 and 2.10 % disease incidence. Dry fibre yield was highest (30.33q/ha) in the plots treated with FYM @ 5t/ha + seed treatment with Azotobacter and PSB @ 5g/Kg+ T. viride (seed treatment @ 5g/Kg of seed and soil application @ 2Kg/ha at 21DAS) + P. fluorescencs spray @ 0.2% at 45DAS) and it was lowest in untreated control (15.69 q/ha).Variation in yield was attributed due to difference in plant height.

In the present study efforts were made to explore the efficacy of various plant extracts and oil cakes against Macrophomina phaseolina. The efficacy of eight different plant species, Zingiber officianale, Aloe indica, Lawsonia inermis, Chenopodium album, Allium cepa, Piper betel, Murraya koenigii, Parthenium hysterophorus aqueous extracts including oil cakes of mustard and neem were evaluated by using of poisoned food technique in vitro for their inhibitory effect on mycelial growth of M. phaseolina causing stem rot of jute (Corchorus olitorius and C. capsularis). The rhizome extract of Z. officinale produced maximum growth inhibition (74.59%) of the pathogen followed by leaf extracts of A. indica (63.57%), and leaf extract of L. inermis (60.17%) at the concentration of 10%. The maximum mycelial growth inhibition (52.40%) was recorded with neem cake (Azadirachta indica) at the concentrations of 20% followed by 42.61% and 29.60% with concentration of 15% and 10%, respectively. However, maximum mycelial growth inhibition (19.42%) was recorded with mustard cake (Brassica juncea) at the concentration of 20% followed by 16.64% and 12.20% at the concentration of 15% and 10% respectively. In general mycelial growth inhibition was dose dependent and it was maximum in case of neem cake than mustard cake. The present study revealed that, these plant extracts and oilcake extracts could be exploited for the possible control of deadly pathogen M. phaseolina. Accordingly, this is an important proactive measure in preventing the spread of the stem rot disease through a more ecofriendly approach.

The toxicity of various extracts of Lantana camara L. leaves was investigated against Cadra cautella (Walker) eggs, larvae and adults. For eggs and larvae film residue method and for adults specimen tube method was followed, then it was compared with azadirachtin technical (20 %). The toxicity of various extracts on egg, larval and adult mortality was compared. The egg mortality was based on their hatchability. It was observed that through film residue, most of the extracts of L. camara showed higher mortality as compared to azadirachtin. Based on LC50 values methanol fraction of hexane extract (LC-3) and hexane extract of hexane fraction (LC-4) of L. camara were found to be most effective against different stages of C. cautella. The mortality was dose dependent and it increased with increasing concentration. The leaf extracts of L. camara were positively toxic to insects. The effects of various extracts on different stages of C. cautella are discussed.

Biotic stresses, particularly insect attacks, adversely affect the yield potential and the fibre quality of jute and allied fibre crops. Insect and mite pests attack these plants at seedling, growth and fibre development stages. Moreover, fibre crops have witnessed the effect of the gradual shift in the climatic pattern in terms of increased diversity and intensity of biotic stresses. The pest outbreaks in these crops have become more frequent which elevated the minor pests to the status of major pests. Considering the occasional, low-input management strategy adopted in these crops, the enhanced pest status of the existing pests, greater severity and the report of many new insect pests indicates the role of various biotic and abiotic stresses in triggering this dynamism in the pest scenario. The report of cotton mealybug, gram pod borer and safflower caterpillar in jute indicates the emerging new pests which may cause economic damage in future. The infestation of yellow mite, Polyphagotarsonemus latus in jute, and Bihar hairy caterpillar, Spilosoma obliqua in all fibre crops, is more regular and so severe that the situation may reach the status of outbreaks. The scenario is more or less same in the allied fibre crops. Published information on arthropods of jute and allied fibre crops is meagre. A few natural enemies and pollinators have been listed on fibre crops, but the attempt to utilize them is wanting. Considering the cost of cultivation and profitability, it is important to develop a low-cost, easily adoptable integrated pest management (IPM) technology for these crops including natural enemies.

Toxicity of conventional (profenofos 50 EC and λ-cyhalothrin 5 EC) and non-conventional (flubendiamide 480 SC, chlorantraniliprole 18.5 SC, emamectin benzoate 5 SG) insecticides was determined on the basis of median lethal concentration (LC50) values on third instar larvae of jute hairy caterpillar, Spilarctia obliqua under laboratory conditions. Further, the promising binary insecticides combinations with lesser LC50 values and adequate synergistic activity were evaluated under field conditions. The LC50 values calculated for insecticides viz., chlorantraniliprole, flubendiamide emamectin benzoate, λ-cyhalothrin and profenophos were 0.212, 0.232, 0.511, 0.985 and 3.263 ppm, respectively. Likewise, the LC50 values for flubendiamide with λ-cyhalothrin in 3:1 proportion was most toxic (0.103 ppm) amongst all the other binary combinations with λ-cyhalothrin. Chlorantraniliprole in combination with λ-cyhalothrin at 1:1 proportion (0.209 ppm) was most toxic followed by 3:1 proportion (0.345 ppm). Similarly, emamectin benzoate in combination with λ-cyhalothrin at 1:1 proportion was more toxic (0.271 ppm) than 3:1 ratio (0.333 ppm). Toxicity index of flubendiamide + λ-cyhalothrin (3:1 ratio) was highest (970.87). Bioefficacy of synergistic binary combinations along with individual insecticides established the superiority of profenophos + λ-cyhalothrin (3:1) with 89.12% reduction in infestation and recorded maximum fibre yield 38.67qha' under field condition. Moreover, combination of diverse insecticides group might sustain toxicity against the target insect for longer period with least probability of resistance development.

The influence of different bast fibre crops i.e. jute (Corchorus olitorius and C. capsularis), mesta (Hibiscussabdariffa and H. cannabinus), ramie (Boehmeria nivea) and sunnhemp (Crotalaria juncea) on biology and life table parameters of jute hairy caterpillar, Spilarctia obliqua Walker was carried out to understand the host suitability under laboratory condition. Adult longevity and fecundity of S. obliqua and its life table parameters were differed significantly with bast fibre crops. The larval, pupal period and adult longevity of S. obliqua were shortest on C. olitorius and longest on H. sabdariffa. The larval survival and adult fecundity (eggs/female) significantly highest (80.68 ± 1.41%, 477.00 ± 21.12 eggs) in C. olitorius and the lowest (53.92 ± 1.20%, 260.00 ± 21.41 eggs) was on H. sabdariffa, respectively. The net reproductive rate was higher on C. olitorius (384.84 ± 21.56 females/female/generation) and minimum (163.80 ± 14.65 females/female/generation) on H. sabdariffa. The intrinsic rate of natural increase was higher on C. olitorius (0.15 ± 0.00 females/female/day) and lowest (0.12 ± 0.00 females/female/day) on H. cannabinus. The study indicated that C. olitorius was the most suitable host as compared to other crops for S. obliqua growth and reproduction.

The fungal entomopathogen Beauveria bassiana is a promising biocontrol agent for many pests. Some B. bassiana strains have been found effective against jute pests. To monitor the survival of field released B. bassiana a rapid and efficient detection technique is essential. Conventional methods such as plating method or direct culture method which are based on cultivation on selective media followed by microscopy are time consuming and not so sensitive. PCR based methods are rapid, sensitive and reliable. A single primer PCR may fail to amplify some of the strains. However, multiplex PCR increases the possibility of detection as it uses multiple primers. Therefore, in the present investigation a multiplex PCR protocol was developed by multiplexing three primers SCA 14, SCA 15 and SCB 9 to detect field released B. bassiana strains from soil as well as foliage of jute field. Using our multiplex PCR protocol all the five B. bassiana strains could be detected from soil and three strains viz., ITCC 6063, ITCC 4563 and ITCC 4796 could be detected even from the crop foliage after 45 days of spray.

A survey on native natural enemies of Bihar hairy caterpillar, Spilosoma obliqua Walker was conducted during April- August 2012 cropping season at ICAR-CRIJAF, Barrackpore as well as jute growing belts in West Bengal, India. The survey revealed that Protapanteles obliquae (Wilkinson) (Braconidae: Hymenoptera) is a potential larval parasitoid of S. obliqua which is occurring naturally on jute. This is the first record of natural parasitism of P. obliquae on S. obliqua on jute crop in India.

The study was undertaken to assess the infestation of yellow mite and semilooper on jute in different dates of sowing. The results revealed that the early sown crop suffered more with yellow mite infestation and there was no significant effect of sowing times on semilooer infestation. There was no significant effect of insect pest pressure on fibre yield of the jute crop. Crop grown on mid-April was found to be more optimum with maximum of 30.30 q/ ha fibre yield.