Scientists say warming climate conditions and changing rainfall patterns appear to be attracting the elephant insect for the first time to Assam
MAJULI, India (AlertNet) - As soon as dusk sets in, the farmers in parts of Majuli island rush back home. They dare not go out in search of cattle, goats and hen gone astray. They shut themselves inside their houses from approximately 6 pm to 7:30 pm.
Anyone who ventures out during that time would be chased by swarms of small beetles - so much so that people avoid riding a bicycle or motorcycle during this time as the insects get into the riderÂ?s eyes and cause accidents.
"The insects make a whirring sound, which sounds almost like the onset of a storm and it flies swiftly and is likely to enter the ears, nose and eyes. So much so, we cannot switch on lights in our house as it attracts the insect, or eat anything during that time as the insect might fall on our food," says Prabin Dolakasoria, 38, a farmer from Auniati Jugunidhari village in Majuli, one of the world's largest freshwater delta islands.
Locally known as hati puk (elephant insect) Â? its snout resembles an elephant's trunk Â? the beetle is an invader from Australia that flies around in the evenings during the intense heat of April and May, looking to mate and lay eggs.
Scientists say warming climate conditions and changing rainfall patterns appear to be attracting the pest for the first time to Assam.
But it is the beetle's immature grub that is causing intensifying problems in Majuli, in the upper reaches of the Brahmaputra River, in India's Assam province.
GRUB EATS PLANT ROOTS
The fat white grub, the size of a human finger, lives in the soil for nearly two years before reaching maturity, all the while eating the roots of crops and causing widespread damage.
Initially farmers were baffled when, five years ago, their potatoes, sugarcane, black gram and colocasia fields began to fail.
"We thought it was some kind of plant disease which attacked the very roots of the plants. Then, while digging in the field, we discovered the larvae of the pest, which was new to us. It was mostly found in the previously tilled soil which is softer," Dolakasoria said.
What baffles farmers is that the pest is not affected even by the annual flood waters which submerge most parts of the heavily agricultural island. Older farmers, like Dolakasoria's father Narayan, 68, say they have never seen a pest capable of causing such extensive damage to their crops.
Scientists at Assam Agricultural University at Jorhat, who identified the grubs, say they are particularly damaging because of their long life cycle Â? something not seen before in Northeast India.
"Prior to 2005, the insect was not recorded in any part of the region. Now it has started breeding and has affected the crops of the farmers. It is more lethal because of its biennial life cycle. It takes two years for Â? the insect to grow from an egg to an adult and in these two years it keeps feeding on the roots," said Badal Bhattacharyya, a senior scientist at the agricultural university.
CHANGING WEATHER HELPING PEST SPREAD
Farmers like Anil Chekanidhar, from Modarguri village near Bhakatchapori in Majuli, believe the pests have been attracted by the region's changing climate, with erratic rainfall and early onset of summer. Bhattacharyya corroborates this.
"An insect's life process is governed by abiotic factors like temperature, moisture, soil type. The favourable soil conditions of Majuli Â? high carbon content, high moisture and sandy loamy soil are ideal for the insect to thrive," he said.
Warming conditions have produced a rise in pest activity and a widening of pest ranges around the world over the last two decades, scientists say. The grub now threatening Majuli's farmers has been identified since 2001 in parts of India, Japan, Papua New Guinea and western Australia.
"It is a matter of concern that migratory birds like the Siberian crane, which used to eat the larvae, have stopped coming to Majuli now. This changing pattern of migration can be attributed to the changing weather patterns," Bhattacharyya said.
In recent years, the new white grub has become a severe pest of potato, sugarcane, black gram and Colocasia fields on Majuli island, and has been found in some parts of north India too. The bug, Lepiodiota mansueta, is also causing heavy damage in sugarcane growing areas of around the Indian city of Haridwar, along the Ganges River.
The grubs of another related species, Lepidiota stigma, are causing extensive damage to maize fields in river bed areas with loose sandy soil in some parts of the Indian province of Himachal Pradesh, researchers said.
"The multiplication of the larvae is a matter of concern as it causes economic damage and in turn affects food security. We are trying to mobilize the farmers to kill the adult insect by dipping it in kerosene before it lays eggs," Bhattacharyya said.
PLOUGHING CAN HELP
Scientists have also recommended that farmers deeply plough their fields from the end of July to the middle of August to expose the grubs to predatory birds. Two ploughings over that period can reduce the grub population by 70 percent, they said.
Early sown crops also suffer less compared to late sown crops, the scientists said, and allowing pigs, hens and ducks into the fields to eat the grubs can be a help, as can treating seed and soil with chemicals to discourage the grubs.
With climate conditions growing increasingly unpredictable, it is difficult to ascertain the future impact of this pest on this river island, and whether it will spread to other areas in the region, researchers said.
Teresa Rehman is a journalist based in Northeast India. She can be reached at www.teresarehman.net
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