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The Effect of Temperature and Elevated CO2 on an Agricultural Pest

Paper Reviewed
Satishchandra, N.K., Vaddi, S., Naik, S.O., Chakravarthy, A.K. and Atlihan, R. 2018. Effect of temperature and CO2 on population growth of South American tomato moth, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on tomato. Journal of Economic Entomology 111: 1614-1624.

The future management of pests in agriculture benefits from an understanding of the effects of temperature and atmospheric CO2 concentration on the development, fecundity and survival of insects. This is because future changes in climate are expected to significantly alter the dynamics and status of insect pests.

One such insect that is of growing concern to agriculturalists is the South American tomato moth, which is a major invasive pest with a potential to induce 100% yield losses on tomatos and other solanaceous plants (e.g., potato, eggplant, tobacco and pepino). Yet, to date, there have been no studies quantifying the combined effects of temperature and atmospheric CO2 levels on their population dynamics, despite predictions that both of these variables will increase as a result of future climate change. Hoping to remedy this data discrepancy, Satischandra et al. (2018) examined the impacts of atmospheric CO2 concentration (380 or 550 ppm) and temperature (26, 28, 30 and 32°C) on the life history of the South American tomato moth (Tuta absoluta).

Working at the Indian Institute of Horticultural Research in Bengaluru, India, the five scientists observed that an increase in temperature "reduced the larval developmental time of T. absoluta, whereas the elevated CO2 concentration extended development time." Additionally, they found that total insect fecundity was significantly lower under elevated CO2 at both 28 and 30°C and that there was "a 5-10% higher mortality observed under elevated CO2 than [under] ambient CO2." And with respect to reproduction, Satischandra et al. report that with a rise in temperature from 26-30°C, "T. absoluta reared under elevated CO2 conditions showed lower net reproductive rate, intrinsic and finite rate of increase in comparison to ambient CO2."

Consequently, and in light of the above, it may well be expected that damage caused by the South American tomato moth will be reduced in the future, thanks in large measure to a higher mortality and longer development time induced by elevated CO2 that will weaken the fitness and effectiveness of this pest.

Posted 14 November 2018