Waves of desert locusts — millions strong and stretching up to 7 kilometers (4 miles) long — crossed into India’s western state of Rajasthan from neighboring Pakistan in early May and swarms have since pushed into five different states in search of food.
A swarm can vary from one to several hundred square kilometers — with each square kilometer containing up to 80 million adult locusts.
From Rajasthan, the swarm entered Uttar Pradesh — which borders the capital New Delhi — in the north, Madhya Pradesh in central India and Maharashtra and Gujarat in the west on Thursday, according to India’s agriculture minister.
Other states have been put on alert. Jharkhand in the country’s east, issued a state-wide alert to farmers on Sunday to prepare for locust swarms, according to P K Sannigrahi, senior scientist at the Krishi Vigyan Kendra Knowledge Network in the state.
“Lighting a fire, bursting crackers, banging plates and tins, and playing the drums as well can chase locusts away, these insects can’t tolerate loud noises,” the advisory issued to farmers read.
The New Delhi government also issued an advisory to be prepared if the swarms turned toward the national capital.
Controlling the swarm
Hard-hit states have been carrying out locust control operations that include dispersing the flying insects with drones, tractors, and fire engines.
Rajasthan, which was the first to be impacted by the locusts, has been conducting daily operations since May 22.
“The locusts were sitting in an area that was 7 kilometers (4 miles) long and 1.5 kilometers (0.9 miles) wide. We started the control operations around 1 a.m. (Tuesday) along with the Locust Organization team,” said B R Karwa, a deputy director of Rajasthan’s Agriculture Department.
Karwa added that 11 swarms initially entered the state and three followed the winds onwards toward Madhya Pradesh.
State officials are using 100 tractor-mounted sprayers and 20 fire engines across 11 districts to spray water and pesticides. Drones provided by the central government were also used to spray pesticides in two districts in Rajasthan, according to Karwa. He added that about 70% of the locusts there had been destroyed.
Despite dispersal operations, locust infestations could continue into next month.
“Several successive waves of invasions can be expected until July in Rajasthan with eastward surges across northern India as far as Bihar and Orissa followed by westward movements and a return to Rajasthan on the changing winds associated with the monsoon,” according to the Desert Locust Situation Update issued by the FAO.
The locusts have flown into India from their breeding areas in Pakistan, according to Om Prakash, a Rajasthan-based plant protection officer for the Locust Warning Organization.
While locust invasions can be devastating for communities because they pose a threat to food security, India has so far appeared to have escaped from the worst as farmers have not yet begun to sow the new season’s crops.
“The locusts were sitting on barren land. The winter crops have been cut and it hasn’t rained yet so the new season’s crops have not been sown. Those who planted fodder crops or vegetables could chase the locusts away. This time, there wasn’t much loss,” said Karwa.