Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
increase in temperature will have a greater effect on insects than the rising CO2 condition, the
interactive and combinational effect of both parameters is more significant in influencing insect
pests. Aphids, Aphis craccivora Koch. is one of the threats to groundnut (Arachis hypogaea
L.) growers in all over the country. Understanding the population dynamics of insect pests is
possible through the construction of life tables which are dynamic and function of various
factors that differ with temperature and no studies are available on the construction of life table
considering temperature and CO2 concurrently. Hence, the studies were conducted with the
objectives i. to measure the effects of temperatures and eCO 2 on life table parameters of A.
craccivora on groundnut ii. to predict the aphid pest scenarios during near and distant future
climate change periods at six locations of India.
Methodology
Groundnut (Kadiri-6) seeds were sown in open-top chambers (OTC) at an elevated atmospheric
CO 2 concentration of 550 ± 25 ppm CO 2 and ambient CO 2, aCO 2 (400 ± 25 ppm CO 2) and
crop plants were raised during the entire crop season. Feeding trials were carried out (Srinivasa
Rao et al., 2013) at constant temperatures (20, 25, 27, 30, 33 & 35 ± 0.5°C) and CO2 levels
(550 ± 25 ppm and 380 ± 25 ppm) to study the growth and development of A. craccivora using
CO2 growth chambers and adopting ‘cut leaf’ method. The life table parameters of A.
craccivora were estimated by adopting the TWO SEX–MS Chart software (Chi et al., 2005)
by using primary parameters data of aphids on groundnut foliage from eCO 2 and aCO 2
independently. Non-linear equations were arrived at after plotting this data against tested
temperatures. The future climate data (maximum and minimum temperature- Tmax and Tmin)
projections of the AIB PRECIS emission scenario were considered to estimate future life table
parameters. The future period was designated as near and distant future periods (NF and DF)
with 2021-2050 and 2071-2098 years respectively. The pest status during these periods was
compared over the baseline (BL) period of 1961-1990 using future daily temperature
(maximum and minimum) for 6 groundnut cultivating regions of the country.
Results
Construction of life tables
The life table parameters viz., intrinsic rate of increase ‘rm’, net reproduction rate ‘Ro’,
generation time ‘T’, and finite rate of increase ‘λ’ were estimated across six constant
temperatures and at aCO2 and eCO2. Further, non-linear models were developed and depicted
in figure 1. Results showed that ‘rm’ increased with an increase in temperature from 20°C and
later started declining from 30°C and followed the non-linear trend at aCO 2 and eCO 2. The
‘Ro’ of A. craccivora was higher (79.6) at 27°C with eCO2. The reduction of ‘T’ was evident
from 20°C (12.47 days) to 35°C (6.67 days) at eCO 2 and followed the non-linear trend. ‘λ’, the
indicator of the reproductive value of aphid was found to be increasing from 27-30°C and
Emerging approaches (RS, AI, ML, Drones etc) for crop management &assessment
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