Locusts: The invasion of the food snatchers
Locust invasions are common in parts of Rajasthan abutting Pakistan, but this is the first time they have reached Jaipur, a city 700km from the border.
Swarms of crop-munching desert locusts entered deeper into Rajasthan, Madhya Pradesh and Uttar Pradesh over the weekend and are now close to the national capital, according to officials who said on Monday that they have put farmers on high alert and deployed insecticide spraying devices through drones, SUVs and tractors.
Locust invasions are common in parts of Rajasthan abutting Pakistan, but this is the first time they have reached Jaipur, a city 700km from the border, after charting a journey that experts believe began in their natural breeding ground in East Africa.
“There is a possibility that the locusts will move towards Delhi in the next few days if wind speeds and directions are favourable. As of today the wind speed moved them towards north,” said the Union agriculture ministry’s Locust Warning Organization (LWO) deputy director KL Gurjar.
Gurjar said the agency was coordinating with the India Meteorological Department to determine the trajectory the insects might take.
On Monday, the swarm reached Jaipur in what was described by officials as unprecedented. An agriculture department official in Uttar Pradesh said that the Jaipur swarm was one of three that was spreading.
“Presently three groups are in action in this area and first one among them was moving towards Jhansi (Uttar Pradesh) based on wind direction. The second lot seems to be heading for Morena in Madhya Pradesh. The third in Jaipur region seem to be heading towards Gangapur city in Rajasthan,” said Ram Pravesh, the district plant protection officer in Agra.
Locusts can fly up to 150km in a day and a one-square-kilometre swarm can eat as much food as 35,000 people, in terms of weight, in a single day, according to the Food and Agriculture Organization (FAO)’s Desert Locust Information Service bulletin.
Locust invasions are known to cause a considerable drop in agricultural output. A moderate infestation chewed through winter crops in an estimated 300,000 hectares in Rajasthan and Gujarat in January. According to some assessments, the locust outbreak this time is linked to climate change and unusual rain.
While there are no crops in Rajasthan at present, the summer-sown season begins next month.
Most of the swarm seen at present consists of pink-hued sub-adult locusts. Officials fear these may arc back to their summer breeding area in the desert between India and Pakistan, where monsoon rains can help trigger a new round of breeding.
“If we are not able to control the sub-adults, they will grow into adults and return to summer breeding sites along the Indo-Pak border in the desert. If there is good rainfall, moisture will make it conducive for egg-laying in sandy soil. We may have to face a second generation of desert locusts then. If they are not controlled in hopper stage then they turn into swarms which will again pose a challenge for us,” said KL Gurjar, deputy director, Directorate of Plant Protection Quarantine and Storage.
The life of a locust varies between three and five months. These insects do not pose a direct risk to animals or humans.
The LWO official said containment strategy depends upon the size of the swarm. “When it enters from Pakistan, a swarm of one square km can have 80 million locusts. As it moves ahead, we keep killing many of them and the swarm becomes less dense but it will still have 40 million locusts,” the joint director said.
“This year, the locust attack is about eight times more aggressive than last year. Last year the locust swarm was first seen in Jaisalmer district on May 21, but this time its swarms started coming in from early May,” he added.
According to officials in Jaipur, the swarm that arrived on Monday was spread 6km wide and stretched on for 2.5km.
Locusts generally settle on vegetation around 8pm and fly off again around 9-10 am the next day, so insecticides are sprayed at them at night to kill them, he added.
The LWO has a ground team of 50 persons mainly to monitor and track the swarms; drones are being used for aerial spraying of Malathion 96, an organophosphate insecticide and a potentially toxic chemical for non-cropped areas. For areas with agriculture, chlorpyrifos is sprayed by drones, fire brigades and tractor mounted sprays.
“This year, we are able to launch control efforts only around midnight because they are settling late. The current breed of locusts unsettles on hearing sound of tractors, making our job more difficult. An unsettled swarm is highly mobile and can travel as much as 150 km a day if winds are favourable,” said Rajasthan’s agriculture commissioner Om Prakash.
