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Global warming may affect pesticide effectiveness

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Image Source- www.sciencedaily.com

New Delhi: The effectiveness of an important mosquito-fighting insecticide may be impaired by global warming, according to a recent study.

Two researchers from Montana State University, graduate student Shavonn Whiten and Robert Peterson, have shown that permethrin becomes less effective at killing the yellow fever mosquito (Aedes aegypti) as temperatures increase.

These mosquitoes, which are found in the tropics and the subtropics, can transmit viruses that lead to dengue, chikungunya, yellow fever, and other diseases.

“Many of the areas where these insecticides are employed have varying drastic temperature changes,” Shavonn Whiten said.

The researchers exposed adult mosquitoes to varying concentrations of permethrin at a range of temperatures.

They found an inverse relationship between death and temperature from 16 AoC to 30 AoC, which showed the highest negative correlation.

From 30 to 32, there was, however, a positive correlation between mortality and temperature. And from 32 to 34, the negative correlation resumed.

“It probably has something to do with variability and heat stress,” said Peterson.

“Once you get to those higher temperatures, there are other things going on regarding stress on the mosquito that cancel out the effect of the pyrethroids (a class of pesticides to which permethrin belongs) working better at lower temperatures and worse at higher temperatures,” he explained.

People involved in mosquito-control efforts should take temperature into account when choosing a pest control product, researchers said.

The study was published in the Journal of Medical Entomology.

(IANS)

Next Story

Ice Loss in Antarctica and Greenland Increasing at an Alarming Rate: Scientists

Greenland, Antarctica ice loss accelerating

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Ice loss
Earth's great ice sheets, Greenland and Antarctica, were now losing mass six times faster than they were in the 1990s due to warming conditions. Pixabay

Earth’s great ice sheets, Greenland and Antarctica, were now losing mass six times faster than they were in the 1990s due to warming conditions, the media reported on Thursday citing scientists as saying.

A comprehensive review of satellite data acquired at both poles was unequivocal in its assessment of accelerating trends, the BBC quoted the scientists as saying.

Between them, Greenland and Antarctica lost 6.4 trillion tonnes of ice in the period from 1992 to 2017.

Ice loss
The combined rate of ice loss for Greenland and Antarctica was running at about 81 billion tonnes per year in the 1990s. Pixabay

This was sufficient to push up global sea-levels up by 17.8 mm, the scientists added. “That’s not a good news story,” said Professor Andrew Shepherd from the University of Leeds.

“Today, the ice sheets contribute about a third of all sea-level rise, whereas in the 1990s, their contribution was actually pretty small at about 5 per cent. This has important implications for the future, for coastal flooding and erosion,” he told BBC News.

The researcher co-leads a project called the Ice Sheet Mass Balance Intercomparison Exercise, or Imbie, which is a team of experts who have reviewed polar measurements acquired by observational spacecraft over nearly three decades.

The Imbie team’s studies have revealed that ice losses from Antarctica and Greenland were actually heading to much more pessimistic outcomes, and will likely add another 17 cm to those end-of-century forecasts.

“If that holds true it would put 400 million people at risk of annual coastal flooding by 2100,” Professor Shepherd told the BBC.

Also Read- People of All Generation Can Feel Lonely for Different Reasons: Research

The combined rate of loss for Greenland and Antarctica was running at about 81 billion tonnes per year in the 1990s.

By the 2010s, it had climbed to 475 billion tonnes per year. (IANS)