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2018 - 201912020 - 20231
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Subject: Entomology × Author: Simranpreet Kaur × Start date: 2010 ×
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    Influence of abiotic factors on development and behaviour of rice leaf folder, Cnaphalocrocis medinalis (Guenee)
    (Punjab Agricultural University, 2023) Simranpreet Kaur; Suri, K S
    The present studies on “Influence of abiotic factors on development and behaviour of rice leaf folder, Cnaphalocrocis medinalis (Guenee)” were conducted at Punjab Agricultural University, Ludhiana during 2019-22. The impact of variable minimum:maximum temperature for 10:14 h, CO2 and RH on C. medinalis revealed that larval duration, pupal duration, adult emergence, male longevity, female longevity, incubation period and hatchability decreased, whereas female proportion and fecundity of C. medinalis increased with increase in temperature (22:32°C to 26:35°C), CO2 (400 to 450 ppm) and RH (75 to 85%). The shortest larval duration of 7.5 days, pupal duration of 6.0 days, male longevity of 4.5 days, female longevity of 7.75 days, incubation period of 2.25 days, hatchability of 47.19 per cent and least adults emergence (5.25 adults) was recorded at elevated temperature (26:35°C), CO2 (450 ppm) and RH (85%), whereas the maximum fecundity (142.25 eggs) and female proportion (0.99) was recorded at the same elevated conditions. Food consumption, CI, AD and RGR increased, whereas ECI, ECD and RCR of C. medinalis larvae decreased with increase in temperature, CO2 and RH. Maximum food consumption (0.0450 g larva-1), CI (0.0965), AD (84.43%) and RGR (0.0770 mg mg-1day-1) was recorded at elevated temperature (26:35°C), CO2 (450 ppm) and RH (85%). Leaf folding pattern, employing double and multiple leaves for feeding and pupation was witnessed at elevated temperature, CO2 and RH. Activity of enzymes viz. AChE, Esterase, GST, Proteases and SOD in C. medinalis larvae increased as 4.96 μg of free thiol formed/min/mg protein, 9.86 μg of β-napthol formed/min/mg protein, 1.81 mmole of CDNB-GSH conjugate formation/min/mg protein, 3.49 mmol of tyrosine released/min/mg protein and 3.80 units/min/mg protein, respectively, whereas activity of Catalase decreased (7.48 µmoles of H2O2 decomposed/min/mg protein) with increase in temperature from 22:32°C to 26:35°C, CO2 from 400 to 450 ppm and RH from 75 to 85 per cent. Total sugars, reducing sugars, phenols and flavonols in rice plants showed a positive linear regression equation while proteins and amino acids followed a negative linear regression equation, whereas chlorophyll showed a non-linear regression equation with temperature, CO2 and RH. The results of present study would facilitate the adoption of appropriate adaptation measures for C. medinalis management with respect to climate change.
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    Effects of double stranded RNA in Bactrocera dorsalis (Hendel) on guava
    (Punjab Agricultural University, Ludhiana, 2018) Simranpreet Kaur; Sandeep Singh
    The present study entitled “Effects of double stranded RNA in Bactrocera dorsalis (Hendel) on guava” was conducted in the Fruit Entomology Laboratory, Department of Fruit Science and Fruit Biotechnology Laboratory, School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana during 2016-17 and 2017-18. Evaluation of impact of two genes NOA and V-ATPase D on maggots, pupae and adults of B. dorsalis revealed that these two genes were vital for growth and survival of B. dorsalis. Bacteria (Escherchia coli HT115) expressing dsRNA was successfully delivered to maggots and adults through artificial diet containing 10g agar, 120g sucrose, 10g soya peptone, 40g dry yeast, 1g sorbic acid, 6.6g ascorbic acid, 0.1g ampicillin, 0.03g tetracycline and 1000ml water. Silencing of NOA and V-ATPase D genes resulted in mortality of different life stages of B. dorsalis in a dose-dependent manner. Maximum moratlity was observed in maggot, pupa and adult stages of B. dorsalis after feeding of bacteria expressing dsRNA at 700µl concentration followed by bacteria expressing dsRNA at 350µl and 200µl concentrations for both NOA and V-ATPase D genes as compared to control (bacteria without dsRNA). Silencing of target genes had greater impact at higher concentrations of bacteria expressing dsRNA. Thus, utilization of this novel strategy might help to manage population of B. dorsalis in guava and may further strengthen the Integrated Pest Management module for B. dorsalis in Punjab after carrying out further research on these aspects.