Loading...
Thesis
Browse
Search Results
ThesisItem Open Access Characterization of resistance in maize to shoot fly, Atherigona naqvii Steyskal(Punjab Agricultural University, Ludhiana, 2019) Goyal, Sunit; Jinda, JawalaShoot fly, Atherigona naqvii Steyskal, is a major pest of spring sown maize in North India. Among different IPM components, host plant resistance is a promising alternative for insecticides to manage this pest. The characterization of maize inbreds, selected on the basis of their differential susceptibility to shoot fly, was carried out under epiphytotic conditions created by broadcasting moistened fish meal at seedling emergence. Eggs laid per plant by shoot fly varied non-significantly among the genotypes. So, the antixenosis for oviposition to A. naqvii was not exhibited by the inbreds. The genotypes were grouped into three classes on the basis of deadhearts incidence as well as susceptibility index which involves egg laying preference, antibiosis and tolerance mechanisms of resistance. The inbreds, SO1SHYQBBB13B, HK12–6–2–4, DMSC 28, Winpop 8, CM 143 and CML 420 were categorized as resistant; IIMRPPBT POOL, (CM 140 × LM 20)-1-1-1-2-1, (CM 140 × LM 20)-2-1-1-1-1, (CM 140 × LM 20)-1-2-2-1-1, IIMRSBT POOL, LM 20, (CM 140 × LM 20)-1-2-1-1-1 and CLQRCYQ 42 as moderately resistant; and (CM 140 × LM 20)-2-3-1-1-1, CM 140, S87P66QBBB 30, LM 16 and SE 563 as susceptible to shoot fly. Antibiosis and Tolerance mechanisms were found associated with resistance to shoot fly in test inbreds. Antibiosis was recorded in terms of significantly prolonged larval (by ~2.5 days) and pupal (by ~1.5 days) period; lower larval (52.23–61.43 %) and pupal (54.29–61.92 %) survival; and lower larval (3.00–3.56 mg) and female pupae (3.07–3.63 mg) weight, in resistant genotypes. Whereas, the susceptible checks, SE 563 and LM 16, displayed significantly higher larval (82.78–77.04 %) and pupal (72.47–69.13 %) survival; and higher larval (3.86–4.08 mg) and female pupae (4.03–4.42 mg) weight. Tolerance, in terms of less proportion of deadhearts out of shoot fly incidence, was higher in resistant inbreds (29.46–33.58 %) in comparison to the susceptible inbreds SE 563 and LM 16 (46.31–47.44 %). The plant characters like high seedling vigour, less leaf area and thin stem were associated with resistance to shoot fly. Among biochemical constituents, the susceptible inbreds exhibited higher contents of dietary elements like total soluble sugars, proteins and amino acids. Whereas, resistant inbreds exhibited higher contents of secondary metabolites like phenols and tannins; and activities of defense related enzymes like phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO). A significant induction of these secondary metabolites, after shoot fly infestation, was also higher in resistant genotypes in comparison to the susceptible ones. Stepwise regression revealed that the deadhearts incidence was significantly influenced by seedling vigour (65.2 %), leaf area (7.5 %) and number of leaves per plant (2.8 %). The shoot fly survival and development were significantly influenced by PAL activity which explained 71.5, 82.9, 47.0, 29.8 and 39.9 per cent variation in larval period, per cent pupation, pupal weight female, pupal weight male and adult emergence, respectively. PPO activity significantly influenced the pupal period (R2= 59.7 %); and amino acids, proteins and total soluble sugars had significant impact on larval weight (R2= 74.9 %). These physico-chemical characters of the maize inbreds can be utilized as reliable markers traits in shoot fly resistance breeding programmes.ThesisItem Restricted Bio-intensive management of sucking pests of tomato under protected conditions(Punjab Agricultural University, Ludhiana, 2019) Nair, Indu J.; Sharma, SudhenduThe present study was conducted in February-May during the years 2018 and 2019 at screenhouses in Entomological Research Farm and New Horticulture Orchard, PAU, Ludhiana. There were a total of three experiments in which different sticky traps, biopesticides and a bioagent- Chrysoperla zastrowi sillemi (Esben-Peterson) were evaluated against sucking pests of tomato grown under protected cultivation. Yellow sticky traps of different colours (yellow, blue and silver) and different shapes (rectangular, circular and triangular) were evaluated and the yellow rectangular sticky traps proved better in trapping aphids and whiteflies in tomato compared to other colours and shapes. Therefore, yellow coloured rectangular sticky traps were evaluated at different rates viz; 2, 4 and 6 traps per 250m2 for tomato under protected conditions. For trapping aphids, the installation rate of 4 and 6 traps per 250 m2 were found effective. Likewise, these traps @ 2, 4 and 6 per 250 m2 were effective in reducing the population of whiteflies. Hence, the rate of 4 traps/250 m2 can be effectively installed in the screen houses against the aphids as well as whiteflies. Among the various biopesticides evaluated, Azadirachtin 0.15% @ 10ml/L of water was found to be statistically superior to the entomopathogenic fungi- Lecanicillium lecanii (1.5%), Beauveria bassiana (1.15%) and Metarhizium anisopliae (1%). Per cent reduction over control also showed that Azadirachtin 0.15% @ 10ml/L provided a maximum reduction up to 58.0 per cent against aphids and 60.0 per cent against whiteflies. Three releases of C. zastrowi sillemi grubs were made @ 4, 5 and 6 grubs/plant to evaluate the predatory potential of the bioagent. The release rate of 4 grubs/ plant was statistically at par with the other rates of release and it recorded a control of more than 90 per cent, seven days, after the first release was conducted.ThesisItem Open Access Estimation of fenazaquin residues in brinjal, okra and soil(Punjab Agricultural University, Ludhiana, 2019) Sandeep Kaur; Kang, Balpreet KaurSupervised field trials were conducted to study the residues of fenazaquin in brinjal and okra following its application at minimum effective (25 g a.i. ha-1), double the minimum effective (50 g a.i. ha-1) and the recommended dose (125 g a.i. ha-1), respectively. The samples were collected at 0 (2 hrs), 1, 3, 5, 7, 10 and 15 days after its application at an interval of 10 days. Sample processing was done following QuEChERS methodology and quantification by High Performance Liquid Chromatography (HPLC) followed by confirmation with Liquid Chromatograph-Mass Spectrometry (LC-MS). The mean initial deposits of fenazaquin on brinjal were 0.046, 0.098, 0.174 and 0.048, 0.102, 0.170 mg kg-1 following its last application during 2017-18 and 2018-19, respectively. For the corresponding doses on brinjal, the residues declined below limit of quantification (LOQ <0.01 mg kg-1) after 3, 5 and 7 days following its last application. The average initial deposits of fenazaquin on okra were 1.663, 2.037, 3.117 and 1.611, 2.299, 3.100 mg kg-1 during 2017-18 and 2018-19, respectively. The residues declined below LOQ at 7, 10 and 15 days during 2017-18 whereas during 2018-19 the residues reached below LOQ after 15 days following application of fenazaquin at all the three doses, respectively. Residues of fenazaquin were found below LOQ in the soil samples collected after 15 days of last application from both brinjal and okra fields. The half-life of 0.75, 1.16, 1.43 and 1.62, 1.75, 1.92 days in brinjal and okra was calculated following its last application at all the three doses, respectively. The average initial deposits observed at recommended dose were more than maximum residue limit of 0.01 mg kg-1 so, the waiting period of 7 and 15 days is suggested for safe consumption of brinjal and okra. Leaching studies showed the presence of fenazaquin residues in the upper layer (0-15 cm) only in the soil columns installed under field capacity and flooding conditions at different time intervals. None of the residues were detected in the leachate collected under both these conditions.ThesisItem Open Access Life table studies of Helicoverpa armigera (Hübner) in tomato(Punjab Agricultural University, Ludhiana, 2019) Damanpreet; Chandi, Ravinder SinghLife table studies of Helicoverpa armigera (Hübner) were carried out in tomato with respect to its biology and life tables under field and laboratory conditions during 2018 and 2019. The duration of different developmental stages of H. armigera was maximum in main season crop and minimum in spring season crop. As compared to the spring season crop, main season crop was more favourable for the development and reproduction of H. armigera. The maximum growth index was observed in main season crop (2.55±0.26) as compared to spring season crop (1.42±0.10) which indicated that H. armigera grew well on main season crop. The life table studies under field conditions in main and spring season crop revealed that in main season crop, highest mortality occurred in early larval instar stage followed by late larval instar stage, egg stage and pupal stage whereas, in spring season crop, egg stage was found to be the most vulnerable/susceptible stage due to various abiotic factors. Egg inviability, natural enemies and unknown factors were responsible for reduction in H. armigera population under natural conditions. The studies on effect of different alternating temperatures on biology and life table parameters of H. armigera on tomato revealed that the duration of different developmental stages of H. armigera decreased with increase in alternating temperature from 28:15°C to 36:18°C, resulting in shorter life cycle at higher temperatures. The fecundity of females varied from 166.83±3.31 to 557.49±5.17 eggs per female at different alternating temperatures. The highest intrinsic rate of increase (rm) of H. armigera was reported at 28:15oC (0.0764) and 28:18oC (0.0777), whereas lowest was at 36:18oC (0.0560). The net reproductive rate was maximum at 28:15oC (58.35) and minimum at 36:18oC (5.77). On the basis of tested alternating temperature combinations, 28:15oC and 28:18oC at 70±5 per cent relative humidity. were found to be the most favourable conditions for the growth and development of H. armigera.ThesisItem Restricted Bio-intensive management of sucking pests of tomato under protected conditions(Punjab Agricultural University, Ludhiana, 2019) Nair, Indu J.; Sharma, SudhenduThe present study was conducted in February-May during the years 2018 and 2019 at screenhouses in Entomological Research Farm and New Horticulture Orchard, PAU, Ludhiana. There were a total of three experiments in which different sticky traps, biopesticides and a bioagent- Chrysoperla zastrowi sillemi (Esben-Peterson) were evaluated against sucking pests of tomato grown under protected cultivation. Yellow sticky traps of different colours (yellow, blue and silver) and different shapes (rectangular, circular and triangular) were evaluated and the yellow rectangular sticky traps proved better in trapping aphids and whiteflies in tomato compared to other colours and shapes. Therefore, yellow coloured rectangular sticky traps were evaluated at different rates viz; 2, 4 and 6 traps per 250m2 for tomato under protected conditions. For trapping aphids, the installation rate of 4 and 6 traps per 250 m2 were found effective. Likewise, these traps @ 2, 4 and 6 per 250 m2 were effective in reducing the population of whiteflies. Hence, the rate of 4 traps/250 m2 can be effectively installed in the screen houses against the aphids as well as whiteflies. Among the various biopesticides evaluated, Azadirachtin 0.15% @ 10ml/L of water was found to be statistically superior to the entomopathogenic fungi- Lecanicillium lecanii (1.5%), Beauveria bassiana (1.15%) and Metarhizium anisopliae (1%). Per cent reduction over control also showed that Azadirachtin 0.15% @ 10ml/L provided a maximum reduction up to 58.0 per cent against aphids and 60.0 per cent against whiteflies. Three releases of C. zastrowi sillemi grubs were made @ 4, 5 and 6 grubs/plant to evaluate the predatory potential of the bioagent. The release rate of 4 grubs/ plant was statistically at par with the other rates of release and it recorded a control of more than 90 per cent, seven days, after the first release was conducted.ThesisItem Restricted Impact of thiamethoxam on Apis mellifera Linnaeus in mustard(Punjab Agricultural University, Ludhiana, 2019) Karedla Ashok Kumar; Choudhary, AmitBees, the important pollinators of oilseed brassica crops, are affected by the usage of thiamethoxam against sucking pests in mustard. Hence, studies were carried out to assess its impact on Apis melliefra Linnaeus. Laboratory studies carried out at Punjab Agricultural University, Ludhiana showed the median lethal values (LD50 dermal & oral) at 24 h to be 7.63 & 5.49 for A. mellifera and 5.45 & 1.98 ng bee-1 for Apis cerana cerana Fab., respectively. Hence, as per Environmental Protection Agency (EPA), thiamethoxam was highly toxic to hive bees. Hazard Quotient (HQ) categorization end point values were >50 which necessitated the conduct of higher tier studies. Chronically fed thiamethoxam to newly emerged bees at the highest consumption (1.09 ng bee-1 day-1) reduced the acini area by more than 50 per cent. Higher tier studies i.e. field trials conducted by applying thiamethoxam 25WG (Actara®) on Gobhi Sarson (GSC 7) revealed that the development of brood marked after 7 days of application of thiamethoxam @ 25 g a.i. ha-1 was unaffected. In contrary to this, brood marked at the day of application of thiamethoxam (@ 25 and 50 g a.i. ha-1) or on 7th day of application of thiamethoxam (@ 50 g a.i. ha-1) was adversely affected. Field collected bees on 3rd day of application from both the thiamethoxam treatments did not show PER response, however it improved with the passage of time and on 15th day of application, the response was the significantly higher than the values recorded at other days. At the recommended dose of thiamethoxam, mortality was very high (134.81-331.88 bees) for the first three days and decreased thereafter, to be statistically at par with untreated control on 8th day of application. This also affected the mean bee strength and unripe honey hoarding in a colony, those also started increasing on 7th day of application (6.95 bee-frames & 2787.41 g) and became significantly higher than pre-treatment on 14th day of application (8.19 bee-frames & 3780.96 g). The mean ripe honey hoarding did not decrease below pre-treatment. The mean unsealed worker brood also showed similar trend i.e. reduction upto 7th day of application (612.09 cm2) and statistically at par with pre-treatment on 14th day of application (688.20 cm2) but the pollen hoarding decreased upto 14 days (290.30 cm2) and on 21st day of application (372.79 cm2) became significantly more than pre-treatment. The initial residues (mg kg-1) recorded in dead bees (0.45), bee foraged nectar (0.02), bee foraged pollen (0.07) and bee bread (0.07) dissipated below LOQ (0.01 mg kg-1) at D5 , D3, D5 and D7 after application, respectively. Consequently bees' activity recorded at colony entrance and on crop blooms too decreased. The effect of double the recommended dose was more pronounced. Overall, it can be concluded that thiamethoxam had negative effect on A. mellifera colonies. Hence, farmers must not apply thiamethoxam on mustard crop during peak activity of bees.ThesisItem Restricted Arthropods diversity under paired row direct seeded rice and management of its major insect pests with biopesticides(Punjab Agricultural University, Ludhiana, 2019) Navjot Kaur; Randhawa, Harpal SinghThe present studies were conducted at Rice Research Area, Punjab Agricultural University, Ludhiana and PAU, Regional Research Station (RRS), Gurdaspur during kharif 2017 to determine arthropods diversity under paired row direct seeded rice and bio efficacy of biopesticides against major insect-pests of rice. The experiment on arthropods diversity was laid out with three dates of sowing and sprayed/unsprayed conditions. The Overall highest arthropods diversity was recorded with second date (first fortnight of June) followed by third (second fortnight of June) and first (second fortnight of May) date of sowing. The higher arthropods diversity was recorded at Gurdaspur as compared to Ludhiana. The maximum incidence of leaffolder and stem borers and population of planthoppers was observed in third (second fortnight of June) date of sowing at both the locations. The leaffolder incidence and planthoppers population was higher at Gurdaspur whereas stem borers damage was higher at Ludhiana. The experiment on bio-efficacy of biopesticides was also conducted at both the locations (Ludhiana and Gurdaspur). It was found that the biopesticides i.e. Neem baan (azadirachtin 1%) @ 3 ml/litre of water was more effective against leaffolder, stem borers and planthoppers. The Beauveria bassiana @ 10 ml/litre of water was also found effective against leaffolder and planthoppers whereas Bt (Delfin WG) @ 10 g/litre of water was effective only against stem borers. The highest cost-benefit ratio was recorded in treatment with chlorpyriphos @10 ml/litre of water followed by Neem baan @ 1 & 2 ml/litre of water. Although comparatively less cost-benefit ratio was observed with biopesticides yet these were safer to our environment and natural enemies. Therefore, it is suggested that farmers should prefer to spray biopesticides for management of insect-pests.ThesisItem Open Access Structural and functional characterization of double sex (dsx) gene in Bemisia tabaci (Gennadius)(Punjab Agricultural University, Ludhiana, 2019) Brar, Gagandeep Singh; Satnam SinghDouble sex (dsx) homologues in Bemisia tabaci were identified and the identification of these dsx homologues in B. tabaci assisted in characterizing several sex-specific transcripts in both male and female separately. These transcripts show that Btdsx consists of six exons and five introns, which are sex-specifically spliced to produce male and female BtdsxM and BtdsxF transcripts. The pre-mRNA of Btdsx produces four male (BtdsxM1, BtdsxM2, BtdsxM3 and BtdsxM4) and one female-specific (BtdsxF) isoforms. All the four male-specific and one female specific BtDsx proteins share common OD1 domains and differ in their OD2 domains at C-terminal sequences. These differences in the exon/intron organization propose that the splicing of Btdsx results from a different functional mechanisms of double sex gene. Btdsx shared a close phylogenetic relationship with dsx of insects belonging to order Hemiptera and Diptera. Further, RT-qPCR analysis revealed that the expression of Btdsx was higher in female adults than male adults as well as other developmental stages including egg, crawlers, second instar nymphs, third instar nymphs and male and female red-eyed pupa. The functional characterization of Btdsx was performed through RNAi using membrane feeding of dsRNA (dsdsx) against dsx in comparison to dsRNA against green fluorescent protein gene (dsGFP). The knockdown effect of Btdsx on other sex related (Vitellogenin (vg) and Vitellogenin receptor (vgr)) and autosomal genes (cytochrome p450 (CYP450) and alkaline phosphatase (ALP)) was also performed using RT-qPCR. Four different combinations (dsdsx fed ♂+ dsdsx fed♀; dsdsx fed ♂ + dsGFP fed ♀; dsGFP fed ♂ + dsdsx fed ♀; dsGFP fed ♂ + dsGFP fed ♀ (control)) of male and female whitefly were used to feed 400 ng dsRNA of Btdsx and GFP (control) per μl of artificial diet for 48 hours. Effect on fecundity, hatching percentage and male: female ratio was observed. Knockdown of Btdsx resulted in significant reduction in expression of dsx in both male and female as compare to control. The expression of vg and vgr showed upregulation in dsdsx fed males. However, it was significantly reduced in dsdsx females as compare to control. The knockdown of Btdsx caused significant reduction in the expression CYP450 and ALP as compared to GFP control. The least fecundity (8.27 eggs/pair) was recorded where dsx was knockdown in both male and female whitefly compared to all other combinations. It was also observed that the knockdown of dsx only in females (12.3 eggs/pair had more impact on fecundity compared to alone males (15.06 eggs /pair). Per cent egg hatching was also least where dsx was knockdown in both the sexes (68.52) or either in females (61.60) or males (68.83) compared to GFP control (85.46). The knockdown of dsx did not had any effect on female: male ratio in any of the combinations.ThesisItem Restricted Evaluation of biogas for the control of pulse beetle callosobruchus maculatus (Fab.) Infesting stored moong(Department of Entomology PAU-Ludhiana, 2002) Singh, Jasbir; Sharma, D. R