Over the last few days, swarms of locusts have been sighted in urban areas of Rajasthan, which is unusual. Swarms have also been reported from parts of Madhya Pradesh and Vidharbha region of Maharashtra. They are now threatening crops in The first swarms were sighted along the India-Pakistan border on April 11, months ahead of the usual time of arrival. This is the biggest locust attack in last 25 years.
What are locusts and when are they sighted in India?
The desert locust is a short-horned grasshopper. Innocuous when solitary, locusts undergo a behavioural change when their population builds up rapidly. They enter the ‘gregarious phase’ by forming huge swarms that can travel up to 150 km per day, eating up every bit of greenery on their way. These insects feed on a large variety of crops. If not controlled, locust swarms can threaten the food security of a country. At present countries in the Horn of Africa such as Ethiopia and Somalia are witnessing one of the worst locusts attacks in the last 25 years.
Why are locusts being seen in urban areas?
Locusts are being seen in areas not historically associated with such sightings — Jaipur, MP’s Gwalior, Morena and Sheopur, and recently stray swarms in Maharashtra’s Amravati, Nagpur and Wardha. The locusts have moved across states attracted by green cover. “The swarms were aided by high-speed wind and thus they made their way to Jaipur. At present there are three to four swarms in Rajasthan, another two or three in Madhya Pradesh, from where a small group has migrated to Maharashtra, are now spreading into UP and Punjab.
What led to their early arrival?
This can be traced back to the cyclonic storms Mekunu and Luban that had struck Oman and Yemen respectively in 2018. These turned large deserts tracts into lakes, facilitating locust breeding that continued through 2019. Swarms attacking crops in East Africa reached peak populations from November, and built up in southern Iran and Pakistan since the beginning of 2020, with heavy rains in East Africa in March-April enabling further breeding.
What can it mean to crops in India?
At present, chances of crop damage are low given that farmers have already harvested their rabi crop. However the orange crops in Maharashtra are under threat and have to be controlled.
The bigger problem will come once the present swarms breed. An adult female locust lays 80-90 eggs thrice in her three-month life cycle. If left uncontrolled, a swarm can grow exponentially to 40-80 million locusts per square kilometre. The locusts will start laying eggs after the monsoon starts and continue breeding for two more months, with newer generations rising during the growth phase of the kharif crop.
Control measures
Control measures involve spraying insecticide on locusts’ night resting places like trees. Till date, spraying has been carried out over 21,675 hectares in Rajasthan. India has also put an order of 60 specialised insecticide sprayers with the UK. India already has 50 such machines. Drones can also be used to spray the resting places in future.
