Determination of thermal constant and development threshold of Bihar hairy caterpillar, Spilarctia obliqua Walker

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

Bioefficacy of plant extracts on stem rot, Macrophomina phaseolina (Tassi) Goid and Bihar hairy caterpillar, Spilosoma obliqua Walker in jute crop

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

Eco-friendly management of major diseases in jute (Corchorus olitorius L.)

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

Bio-efficacy of phytoextracts and oil cakes on Macrophomina phaseolina (Tassi) causing stem rot disease of jute, Corchorus spp.

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

Evaluation of stem rot disease in jute (Corchorus olitorius) germplasm caused by Macrophomina phaseolina (Tassi) Goid

This study was aimed to identify more sources of resistance in jute germplasm (Corchorus olitorius) against deadly disease of stem rot. Thirteen C. olitorius jute germplasm including one standard check (JRO-524) were evaluated against stem rot disease at Barrackpore, Coochbehar and Bahraich location for two consecutive years 2012-2013. Out of thirteen germplasms of jute, six germplasms OIN-853, OIN-651, OIN-154, OIN-125, OEX-27 and OIN-467, with disease rating scale (1.1-5) were found moderately resistant against the stem rot disease at Barrackpore and Bahraich location. Whereas, OIN-270, OIN-932, OIN-270, OIJ-52, OIN-270, OEX-15 and OIN-853 with disease rating scale (5.1-10.0) were found moderately susceptible at all the three location. Rest of the lines were either susceptible or highly susceptible. These germplasm lines OIN-853, OIN-651, OIN-154, OIN-125, OEX-27 and OIN-467, possessed good degree of resistance against stem rot of jute and were found moderately resistant under natural epiphytotic condition at Barrackpore and Bahraich location that would be further exploited for resistance breeding programme against this deadly disease

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Not AvailableWhitefly 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.Not Availabl

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