Weather comes to farmers’ rescue as locust swarms disappear inside NepalExperts say rainfall and low temperature halted their march and minimised damages.
Nepali authorities monitoring the movement of desert locust swarms in the sub-continent are heaving a sigh of relief after the pests, which have left a trail of destruction in Africa and western Asia, “suddenly disappeared”.
Locust invasion, which was seen as a major threat to crops this summer, hasn’t been reported anywhere in the country for the last few days, authorities said attributing it to the movement of monsoon winds from the east, and comparatively lower temperatures due to rain.
“It seems they all are lost somewhere,” said Ram Krishna Subedi, senior plant protection officer at the Plant Quarantine and Pesticide Management Centre under the Ministry of Agriculture and Livestock Development. “They are nowhere to be seen in swarms nor are their activities being reported. They are either isolated or have died,” he told the Post.
Several swarms of the crop-damaging insects were reported to have entered the country on different dates beginning from June 27. It was estimated that around eight million locusts in six swarms may have broken off from a larger swarm and entered Nepal from India. A swarm of nearly 10,000 was reported in Kailali on June 30. They had been spotted in 52 of the 77 districts of the country, including mountainous areas such as Mustang.
“They flew to many hilly districts. Now, they aren’t seen anywhere,” said Sunil Aryal, a senior scientist at the Entomology Department of Nepal Agricultural Research Council (NARC). “Farmers have also killed them. Some might have been living in the jungle, but they are nowhere to be seen,” he added.
The prevailing weather conditions and the country’s climate worked in the country’s favour when it came to taming these insects, which can devour hectares of crops in a day, said experts. Regular monsoon rain not only slowed their march, but also killed many of them, they said.
“We have received rainfall in many districts, mainly in the mid-hills. These desert locusts can not survive at low temperature. According to studies, 15 degree Celsius is the threshold for their survival,” said Aryal. “They could not adapt to our weather.”
According to Aryal, these locusts are known to be flying up to a maximum elevation of 1500-2000m. “They were taken to mountainous districts by the wind. They can not fly against the wind direction so they end up in those districts,” said Aryal.
It was also the prevailing weather conditions that brought these insects into Nepali territory. Wind blowing towards Nepal from the south drove them into the country and pushed them further up to the hilly districts.
Subedi said the insects could not survive the low temperature of the hills. “They got drenched in rain and could not fly further,” he added. “If the wind direction changes and winds blow towards Nepal from the south, they might come again. We are observing their movement.”
Initially, there were no reports of substantial damages caused by locusts in the country. But after a couple of days, reports related to crop damages came pouring in. According to the centre, the locusts damaged crops in Dang (580 hectares) followed by Pyuthan (283 hectares), Makwanpur (105 hectares), Arghakhanchi (100 hectares) and Palpa (50 hectares).
Officials, however, say damages caused by locusts is significantly low compared to what was being dreaded as swarms of locusts entered the country and made their way to several districts.
Meanwhile, the government is yet to decide how farmers who suffered crop damages due to the locust invasion are to be compensated.
“We have received initial crop damage reports, but we need accurate data on damages,” said Subedi. “We need to wait for field visits by officials. A minimum threshold will be set to decide who gets government compensation for crop damages.”
Government agencies are constantly tracking the movement of the locusts. As per the Swarm Trajectory Prediction issued on Monday afternoon, the nearest locust swarm from Nepal has been sighted in Jhansi, Orai and Bhura of Uttar Pradesh, around 550- 600 km south of Bhairahawa. These swarms are projected to move west.
With projections saying that winds will blow from the east towards west in Nepal during the monsoon, it is not likely that the locust swarms will enter Nepal again, at least until the monsoon clouds remain active.
“Locusts are still active in India. They breed in spring and in summer. The second generation of those bred in spring is already flying. The ones bred during the summer have also grown into adults,” said Aryal. “They are likely to form swarms again in late July and early August. Therefore, we are constantly monitoring their movement every day.”