Central Agricultural University

About: Central Agricultural University is a education organization based out in Imphal, Manipur, India. It is known for research contribution in the topics: Population & Agriculture. The organization has 1116 authors who have published 1157 publications receiving 9217 citations.

Mode of inheritance of Indoxacarb resistance in diamondback moth, Plutella xylostella (L.) and cross resistance to different groups of pesticides

Abstract: The development of insecticidal resistance in diamondback moth (DBM) Plutella xylostella has immediate implications for its management In this study, we examined the mode of inheritance of Indoxacarb resistance in P xylostella The indoxacarb-resistant strain (Px-R) was obtained through continuous laboratory selection with increasing doses of indoxacarb in each generation At the 14th generation of selection, the resistance ratio of Px-R strains was 238 over the susceptible strain (Px-S) The mode of inheritance to Indoxacarb in P xylostella was examined performing standard reciprocal crosses between Px-R and Px-S and response of Px-R, Px-S and F1 hybrid progenies to Indoxacarb through leaf dip bioassay The degree of dominance (D) and heritability (h) of F1 hybrid progeny ranged from −0001 to 00012 and 0499 to 0506, respectively The Indoxacarb resistance was appeared to be autosomal and inherited as a semi-dominant trait The Px-R strain of P xylostella showed little cross resistance to cypermethrin and there was no cross resistance to other pesticides viz, chlorpyrifos, spinosad, karanjin, xentari (Bta-Cry1C) and MVP-II (Cry1Ac) Since the Indoxacarb resistance inherited as a semi-dominant trait in P xylostella, the sub lethal doses and frequent use of indoxacarb should be avoided for the management of P xylostella Moreover, Px-R of P xylostella showed positive cross resistance to synthetic pyrethroids (cypemethrin), therefore indoxacarb and synthetic pyrethroids should not be recommended together for management of P xylostella

Uncertainty Assessment in Soil Erosion Modelling Using RUSLE, Multisource and Multiresolution DEMs

Abstract: Soil erosion is a key concern for the environment and natural resources since it leads to a decline in-field productivity and soil quality, resulting in land degradation In this study, assessment of uncertainty in soil erosion modelling of the Karso watershed, India, was carried out by employing the revised universal soil loss equation (RUSLE) and geospatial technologies to evaluate the effect of multi-source digital elevation models (DEMs) [Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Cartosat and Shuttle Radar Topography Mission (SRTM)] with resampled multi-resolution grids The rainfall erosivity factor (R) was computed using the mean monthly Tropical Rainfall Measuring Mission rainfall estimates for 1998 to 2012 The slope length factor was derived using the ASTER and Cartosat DEMs at grid sizes of 30 m, 50 m, 100 m, 150 m, 200 m, and 250 m, and for the SRTM DEM at 100 m, 150 m, 200 m and 250 m resolutions for the Karso watershed, Jharkhand, India Significant differences were obtained in the soil loss estimates across the different DEM sources and resampled grid sizes The Cartosat DEM with a 200 m grid was found to estimate the soil loss the best out of all the DEM combinations considered The Cartosat DEM proved to be more reliable than the ASTER and SRTM DEMs The results indicated that the RUSLE is a scale-dependent model since the model estimates were affected not only by the DEM source but also by its resolution The prediction of erosion potential by employing the multisource, multiresolution DEMs and the RUSLE helped to identify the soil erosion's spatial pattern within the watershed The study provided an impact analysis of the uncertainties when selecting the multisource, multiresolution DEMs for soil erosion modelling

Biological attributes and feeding potential of three dominant predators of Lipaphis erysimi (Kaltenbach)

Abstract: Basic biological attributes and feeding potential of three major predators viz., the seven spotted lady bird beetle Coccinella septempunctata Linnaeus and two syrphids Episyrphus viridaureus (Wiedemann) and Betasyrphus isaaci (Bhatia), of mustard aphid, Lipaphis erysimi were studied under laboratory conditions. The predators were multiplied on mustard aphids reared on mustard plants. C. septempunctata, E. viridaureus and B. isaaci completed their life cycle in 68.5± 6.5 days, 47±2 and 41±2, respectively. Coccinella septumpunctata completed the larval growth with four larval instars, while both the syrphids terminated the larval growth with three instars. Final instars of all the three predators were found to have highest predatory potential than the younger instars. C. septumpunctata was found to be the most dominant predator of mustard aphid with average lifetime consumption of 4312±537.74 aphids, followed by E. viridaureus (416.67±6.76 aphids) and B. isaaci (338±7.89 aphids). All the three predators have the potential to reduce the mustard aphids; however, C. septumpunctata has a maximum predatory potential with a longer life, which makes this species as an excellent bioagent of L. erysimi and further research on their utilization on a large scale should be undertaken.

Field efficacy of certain microbial insecticides against Plutella xylostella Linnaeus and Pieris brassicae Linnaeus under cabbage-crop-ecosystem of Manipur.

Abstract: A field trial was experimented during Rabi, 2014-15 at the Vegetable Research Farm of College of Agriculture, Central Agricultural University, Imphal to evaluate certain microbial pesticides against the diamond back moth, Plutella xylostella Linnaeus and the cabbage butterfly, Pieris brassicae Linnaeus and their effect on the population of lady bird beetle, Coccinella septempunctata Linnaeus in cabbage -crop-ecosystem of Manipur. The results on the efficacy of insecticides against P. xylostella and P. brassicae revealed that all the insecticidal treatments resulted in significantly suppression of both the pests' incidence. However, bioasp ( Bacillus thuringiensis var. kurstaki) @ 1000 g ha -1 was the most effective insecticide against P. xylostella with a record of minimum mean leaf damage of 13.32 per cent as against 69.18% in untreated control, closely followed by spinosad 2.5 SC applied @ 500 ml ha -1 (14.22% LD) which did not differ significantly from each other. Against P. brassicae spinosad 2.5 SC registered significantly the lowest mean leaf damage of 24.30 per cent as against 87.38% in untreated check, closely followed by myco-jaal 10 SC ( Beauveria bassiana ) with a record of 26.59 per cent leaf damage but, differed significantly between them. The highest mean leaf damage incidence (37.47% LD) was noticed in the plots treated with brigade (Vertcillium lecanii) applied @ 1250 g ha -1 . The results on toxic effect of insecticides on the population of C. septempunctata revealed that bioasp ( B. thuringiensis var. kurstaki) @ 1000 g ha -1 proved to be the safest insecticide with significantly highest population of 1.99/ 5 plants as against 3.04/5 plants recorded in untreated control, followed by myco-jaal 10 SC (B. bassiana) @ 500 ml ha -1 (1.61 beetles/ 5 plants) and spinosad 2.5 SC @ 500 ml ha -1 (1.51 beetles/ 5 plants) which did not differ significantly from each other. The lowest population C. septempunctata (0.55/plants) was observed in the malathion 50 EC @ 500 ml ha -1 treated plots. The highest mean cabbage yield (24.77 t ha -1 ) was harvested from the plots treated with spinosad 2.5 SC with the maximum yield increase over control of 9.37 t ha -1 which showed non significant difference with the plots of bioasp ( B. thuringiensis var. kurstaki (23.70 t ha -1 ) with its yield increase over control of 8.30 t ha -1 , whereas verticel ( V. lecanii ) @ 1000 g ha -1 treated plots accrued significantly lowest cabbage yield of 19.27 t ha -1 with a record of lowest yield increase over control of 3.87 t ha -1 . The avoidable yield loss was computed to be 37.82 per cent in the untreated control plots. Application of insecticides resulted in reduction of the mean avoidable loss, which ranged between 4.32 and 22.21 per cent in different insecticidal treatments, the lowest being in bioasp ( B. thuringiensis var. kurstaki) and highest in verticel ( V. lecanii ). The net profit of the insecticidal treatments varied from Rs. 17860.60 (verticel) to Rs. 45621.60 (spinosad) with the cost : benefit ratios ranging between 1:11.99 and 1:43.09, the minimum and maximum being with verticel and myco-jaal 10 SC, respectively.

Coinfection of diarrheagenic bacterial and viral pathogens in piglets of Northeast region of India.

Abstract: Aim This study aimed to study the prevalence of the coinfection of enteric bacterial and viral pathogens, namely Escherichia coli, Salmonella, Rotavirus, and Picobirnavirus from fecal samples of pre-weaned piglets in Northeast region of India. Materials and Methods A total of 457 fresh fecal samples were collected from piglets under 9 weeks old during 2013-2015 from organized (n=225) and unorganized (n=232) farms of Manipur, Meghalaya, Mizoram, and Nagaland. Samples were collected from diarrheic (n =339) and non-diarrheic (n=118) piglets including local indigenous (n=130) and crossbreed (n=327) piglets in different seasons during the study period. The samples were processed for the isolation of E. coli and Salmonella and detection of their putative virulence genes by polymerase chain reaction (PCR). Samples were also processed for the detection of Rotavirus and Picobirnavirus by RNA-polyacrylamide agarose gel electrophoresis and reverse transcriptase-PCR (RT-PCR). Results A total of 11 (2.40%) samples were found positive for two or more coinfecting enteric bacterial and viral pathogens. All the 11 positive fecal samples were recovered from diarrheic piglets. Salmonella Typhimurium (enterotoxin, stn gene) and Picobirnavirus genogroup 1 were found to be more frequent as coinfecting agents. Coinfection was recorded higher in unorganized (3.87%) compared to organized farm (0.88%). Again, higher detection was recorded in crossbreed (2.75%) than local indigenous piglets (1.53%). The occurrence of coinfection was found to be more common during summer (4.68%) followed by winter (2.27%) season. Conclusion The present study highlighted the significance of E. coli, Salmonella, Rotavirus, and Picobirnavirus as important diarrheagenic pathogens causing coinfection in piglets in Northeast region of India. Probably, this is the first systematic study of the coinfection of four important diarrheagenic bacterial and viral agents associated with piglet diarrhea in India.