Millions of locusts have affected around 100 districts in five states of Rajasthan, Madhya Pradesh, Uttar Pradesh, Gujarat and Maharashtra and can reach another 12 in the next few weeks, officials have warned.

They said another swarm from Pakistan is expected to enter India around mid-June, which would provide fuel to locust activity in the region.

The desert locust is a species of swarming short-horned grasshopper, and are known to devour everything in their path, posing an unprecedented threat to food supply and livelihoods of millions of people.

According to the Food and Agriculture Organization’s Desert Locust Information Service bulletin, locusts can fly up to 150 km a day and a one-square-kilometre swarm can eat as much food as 35,000 people in one day.

Authorities in Delhi, Himachal Pradesh, Haryana, Uttarakhand, Telangana and Karnataka sounded alerts on Thursday to the possibility of locusts entering their territories even as the United Nation’s Food and Agriculture Organisation (FAO) has warned that the crop-destroying insects could reach Bihar and Odisha in the east in the coming weeks.

The Delhi government has issued an advisory to officials across various districts to prepare for a potential locust attack after the Centre issued a warning that there was a high chance of the crop-munching insects moving from parts of Madhya Pradesh towards the capital.

The Locust Warning Organisation under the Union agriculture ministry warned that Delhi may be targeted by the swarm which hit Jaipur and Uttar Pradesh on May 25, and parts of Madhya Pradesh last week.

“There is a chance that the swarm in Madhya Pradesh’s Chhatarpur and neighbouring Jhansi area may move towards Delhi. They will settle in the evening and control operations will take place tomorrow morning. But it’s good that Delhi government is on alert just in case a small number reach Delhi from Madhya Pradesh,” KL Gurjar, deputy director of the nodal organisation dealing with a possible locust attack, said.

Similarly, a high alert has been issued in Kangra, Una, Bilaspur and Solan districts after massive swarms of desert locust destroyed crops in adjoining states and that may spread to Himachal Pradesh.

Dr RK Koundal, director of agriculture, said on Thursday that field functionaries have been alerted to keep the continuous and constant vigilance on locust activity and get ready to control any emergency situation, according to an official release.

Farmers have been asked to report any activity of locusts to nearby agriculture officers.

“Desert locusts usually fly with the wind at a speed of about 16-19 km per hour depending on the wind. When swarm settles down in a particular area it should be quickly treated chemically, mechanically beaten and buried by digging trenches,” Koundal said.

“At present, the primary method of controlling desert locust swarms and hopper bands is mainly with organophosphate chemical applied in small concentrated doses (referred to as ultra-low volume (ULV) formulation) by vehicle-mounted and aerial sprayers and to a lesser extent by a knapsack and hand-operated sprayers. Small patches of locust should be immediately sprayed by ULV,” he said.

Koundal further said that all the field officers have been directed to create awareness among the farmers regarding the locust attack.

“Directions have also been given to check its gregarious and solitary forms immediately by spraying contact insecticides,” he added.

Bio-Control Laboratory, Kangra and Mandi have been directed to prepare Metarhizium and Beauveria bio-insecticides at their full capacities.

Haryana has also issued a high alert in seven districts after locust swarms attacked crops in neighbouring Rajasthan and a few other states, officials said on Thursday.

They added that there was enough insecticide in stock to tackle the pest menace.

Tractors mounted with chemical sprayers have also been deployed in Sirsa, Fatehabad, Hisar, Bhiwani, Charkhi Dadri, Mahendragarh and Rewari districts, which are on high alert.

Farmers maintained vigil hundreds of kilometres away in Karnataka’s Bidar as locusts were expected from western Maharashtra, where they reached on Tuesday.

The Karnataka government claimed on Thursday that the chances of a massive locust swarm reaching the state are remote due to change in the wind direction.

“…good thing is that the wind is not blowing towards Karnataka..according to the MET department report wind is expected to be towards a different direction,99.99 per cent it (locust) will not come to Karnataka, so farmers need not worry,” BC Patil, the state’s agriculture minister, said while speaking to reporters.

A committee, comprising agriculture and horticulture directors and senior officials has been constituted and the officials have been directed to visit Kalaburagi, Bidar, Koppal and Yadgir districts.

An official release mentioning the change in the wind direction said the locusts are about 450km away from Bidar district border, and may not reach Karnataka.

Minister Patil stating that according to experts locusts have appeared in large numbers due to good rains last year in Rajasthan and have started moving in an eastward direction now.

“They travel along the wind direction and not against it,” he said.

The minister also said they have stocked pesticide chlorpyrifos and it can be sprayed in case the locusts come.

In Telangana, a five-member committee has been appointed to keep a tab on the movement of the locusts and to monitor measures to prevent the swarms from entering the state.

Fire engines, jetting machines and pesticides were being sent to the entry point areas on the state’s borders with Maharashtra, Madhya Pradesh and Chhattisgarh.

Reports said officials and police in Bhadradri Kothagudem, Mulugu, Jayashankar Bhoopalpally, Mancherial, Asifabad, Adilabad and Pedapalli districts have been put on alert.

The Uttarakhand government has set up district control rooms to coordinate locust control operations. Officials said that drones have also been procured to spray chemicals and fire tenders and trackers with chemicals were on standby for pest control operations.

Favourable breeding weather caused by a large number of cyclones in East Africa is being attributed to the surge in locust attacks since last year. India, China and Pakistan face the most risk in Asia, according to the UN. Pakistan has already declared an agricultural emergency.

Locust attacks are known to cause a considerable drop in agricultural output. A moderate infestation chomped through winter crops in an estimated 300,000 hectares in Rajasthan and Gujarat in January. The crucial summer-sown season begins next month.