India’s rice at risk: Brown planthopper a growing threat as global warming increases

 “The brown planthopper, often in combination with a virus, can cause welting and even dying of rice plants in great parts of India. On certain farms affected, this could lead to huge economic losses to the tune of 70 to 100 percent in commercial rice production per season,“  says Abel Chemura, scientist from the Potsdam Institute for Climate Impact Research PIK and co-author of the study. “This is a huge challenge in India, the second largest producer of rice in the world, and is caused mainly by increasing temperatures due to human-induced climate change.”

To arrive at this conclusion, the team of researchers looked at how environmental factors like annual mean temperature or precipitation influence the distribution and spread of the rice brown planthopper pest. They found that annual temperature fluctuation is the key factor, driving almost 70 percent of its current distribution in India, followed by precipitation patterns.

The scientists then looked at different warming climate scenarios: Currently, the southern and eastern rice-growing areas of the Indian mainland as well as small parts in Northern India are at high pest risk, accounting for ca. 7 percent of the total land area of India suitable for the appearance of the rice pest. About 48 percent of the affected land area in India is at rather low risk, mostly situated in north-western India, and ca. 45 percent is at moderate to mild risk.

When looking at projections of pest developments in India with future climate scenarios, this picture changes drastically: Even if the global temperature rise can be kept below 2 °C, the total area under high pest risk would more than double and increase to more than 15 percent until 2050, while even higher temperatures would lead to an increase of more than 20 percent.


Area statistics of the current and projected shift of the brown plant hopper pest in India under different representative concentrationpathway (RCP) during the 2050 and 2070 climate scenarios. The table shows the area (sq. km) covered under the four possible climate outcomes. Numbers in the staked bars represent percentage area under each outcome.

The prediction for 2070 with a global warming of about 2.4 °C depicts more than 30 percent of Indian rice cultivated areas under severe threat by heavy brown planthopper infestation; a global warming by more than 4 °C would see more than 50 percent of Indian rice areas in danger.

At the same time, areas that today are less suitable for the rice pest would decrease from 48 percent at present to 31 percent and even less as Chemura underlines: “If we do not stop heating up our planet and think about adaption strategies, the brown planthopper pest is not only likely to further cause damage in high-risk areas. It will also spread to previously unsuitable areas in India, affecting additional rice crops and possibly leading to severe food insecurity and economic disruptions throughout the whole of India.”

Projected changes in the distribution map of the brown planthopper pest in India during 2070, based on HADGEM2-AO GCM model among RCP 2.6 (A), RCP 4.5 (B), RCP 6.0 (C) and RCP 8.5 (D) climate scenarios.