Locust Attack

Why in news?

Swarms of locusts are being sighted early in India and in areas not historically associated with such sightings.

What are locusts?

  • The desert locust (Schistocerca gregaria) is a short-horned grasshopper.
  • Solitary phase – In “solitary phase”, these winged insects are safe.
  • They become dangerous only when their populations build up rapidly.
  • Close contact in crowded conditions trigger behavioural changes.
  • Gregarious phase – They enter the “gregarious phase”, by grouping themselves into bands and forming swarms.
  • They travel great distances (up to 150 km daily), while eating up every bit of vegetation on the way.
  • If not controlled at the right time, these insect swarms can threaten the food security of countries.
  • 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.

When are they sighted in India?

  • The first swarms were sighted along the India-Pakistan border on 11th April 2020, months ahead of the usual time of arrival.
  • Agriculture Ministry’s Locust Warning Organization (LWO) reported the first sightings in Rajasthan’s Sri Ganganagar and Jaisalmer districts.
  • In India, locusts are sighted normally during July- October along the Pakistan border.
  • In 2019, parts of Western Rajasthan and Northern Gujarat reported swarms that caused damage to growing rabi crops.
  • These were the first swarms reported in India since 1997.

Why are locusts seen in urban areas?

  • Sightings – Locusts are being seen in areas not historically associated with such sightings.
  • These areas include urban areas of Rajasthan including Jaipur, Madhya Pradesh’s Gwalior, Morena and Sheopur.
  • Also, stray swarms are seen in Vidharbha region of Maharashtra’s Amravati, Nagpur and Wardha.
  • LWO – K L Gurjar, Deputy Director of LWO, said there being no crops in the fields, 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 3 to 4 swarms in Rajasthan, another 2 or 3 in Madhya Pradesh.
  • From Madhya Pradesh, a group has migrated to Maharashtra, which is not very difficult to control.
  • FAO – A senior locust forecaster of the UN Food and Agriculture Organization said the locusts have started moving in search of food.
  • In early-April 2020, the spring-bred swarms from Pakistan started arriving in Rajasthan.
  • As this is before the monsoon rains, they found dry conditions.
  • They continued to move east in Rajasthan looking for green vegetation for food and shelter where they will mature and lay eggs with the onset of the monsoon.

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, 2019.
  • They 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.
  • 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.
  • The newer generations may rise during the growth phase of kharif crop.
  • In May 2020, Union Agriculture Minister Narendra Singh Tomar chaired a meeting to take stock of the situation.
  • Control involves spraying insecticide on locusts’ night resting places like trees using drones.
  • India has also put an order of 60 specialised insecticide sprayers with the UK, with India already having 50 such machines.

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