Browsing by Author "THAKUR, SHAGUN"
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ThesisItem Open Access PREDATORY POTENTIAL OF Blaptostethus pallescens Popp AGAINST Tetranychus urticae Koch AND ITS INTRAGUILD PREDATION ON Neoseiulus longispinosus (Evans)(UHF,NAUNI, 2021-10) THAKUR, SHAGUN; SHARMA, P LABSTRACT The present study entitled “Predatory potential of Blaptostethus pallescens Popp against Tetranychus urticae Koch and its intraguild predation on Neoseiulus longispinosus (Evans)” was carried out in the Biocontrol Laboratory of Department of Entomology, Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP), during 2020-2021. The predatory bug failed to complete its life cycle on all the tested fife stages of T. urticae and could not develop beyond the fourth nymphal instar. However, when Corcyra cephalonica (Stainton) eggs were included in the predator’s diet along with T. urticae for 6 or 12h, the bug developed successfully. The biological and population parameters of the bug were highest on C. cephalonica eggs followed by T. urticae+C. cephalonica (12+12h), T. urticae+C. cephalonica (18+6h). The fecundity was highest (190.4 eggs/female) in females reared exclusively on C. cephalonica eggs followed by those reared on T. urticae+C. cephalonica (12+12h) (117.8 eggs/female) and T. urticae+C. cephalonica (18+6h) (98 eggs/female). The feeding and pest-kill potential of the predator was also higher on C. cephalonica eggs than on T. urticae+C. cephalonica (12+12h) or T. urticae+C. cephalonica (18+6h). The consumption rate of adult male and female predators was 251.8 and 410.8 on C. cephalonica eggs, which was higher than recorded for the predator feeding on T. urticae+C. cephalonica (12+12h) (170.3 and 246.4, respectively) and T. urticae+C. cephalonica (18+6h) (126.3 and 186.8, respectively). The predatory bug exhibited a type II functional response to the target prey and the parameters were higher on proto- and deutonymph than on eggs and adults. The intraguild predation of N. longispinosus by B. pallescens was not strong and the bug predated almost negligible or a few intraguild preys. Based on these results, B. pallescens can be used against T. urticae, but repeated applications may be required, as it will not be able to increase its population exclusively on the mite. Further field studies are, however, required to standardize the release rates. The predatory bug can also be used compatibly with the predatory mite, N. longispinosus as it showed only negligible intraguild predation on the predatory mite.ThesisItem Open Access STUDIES ON THE FOLIAR APPLICATION OF ELICITORS ON PHYTOCHEMICAL CONTENT AND ANTIOXIDANT POTENTIAL OF CHAMOMILE (Matricaria chamomilla L.)(UHF,NAUNI, 2022-10) THAKUR, SHAGUN; SHARMA, ROHITABSTRACT The present investigation entitled “Studies on the foliar application of elicitors on phytochemical content and antioxidant potential of Chamomile (Matricaria chamomilla L.)” were carried out in ICAR field of Medicinal and Aromatic Plants (Majhgaon farm) of Department of Forest Products, Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan during 2021- 2022. The sowing of nursery was done on 21 October, 2021. The seedlings were planted in the raised beds of size 1.8 × 2.4 m at 30 × 30 cm spacing. The experiment comprised of 7 treatments: T0 (Control), T1 (Salicylic Acid, 0.5 mM), T2 (Salicylic acid, 1.0 mM), T3 (Acetyl Salicylic Acid, 0.5mM), T4 (Acetyl Salicylic Acid, 1.0 mM), T5 (Methyl Jasmonate, 0.5 mM) and T6 (Methyl Jasmonate, 1.0 mM). Among these treatments, Methyl Jasmonate at 1.0 mM (T6) was recorded as the best treatment which gave maximum growth and yield : number of leaves per plant (444.60), number of flowers per plant (337.36), fresh herbage yield per plant (340.03 g), dry herbage yield per plant (44.50 g), fresh flower weight per plant (37.80 g), estimated fresh flower yield (41.57 q/ha), essential oil content (0.118%) and estimated essential oil yield (4.91 kg/ha). However, the maximum chlorophyll a (2.04 mg/g), chlorophyll b (1.01 mg/g), total chlorophyll content (3.06 mg/g) and carotenoids content (1.27 mg/g) was recorded in salicylic acid at 1.0 mM (T2). The maximum plant height (72.70 cm) was also recorded in salicylic acid at 1.0 mM (T2). In phytochemical analysis and antioxidant potential, methyl jasmonate at 1.0 mM (T6) gave the maximum phenolic content (104.24±2.19 GAE/g), flavonoid content (157.03±2.22 RE/g), maximum percentage of DPPH radical scavenging activity (54.17±2.03), hydroxyl radical scavenging activity (59.62±0.39), nitric oxide scavenging activity (37.68±2.21) and the maximum absorbance of reducing power activity (0.668± 0.003). The analysis also showed the presence of alkaloids in all the treatments