Daily Editorial Analysis for 28th May 2020

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Locust Swarms


Mains: General Studies-III: Technology, Economic Development, Bio diversity, Environment, Security and Disaster Management


Just last week, eastern India was battered by one of the most powerful cyclones in decades and now, even as hundreds of lives are lost every day to the coronavirus, another danger lurks on the nation’s west.

Key details:

  • A burgeoning locust swarm in Rajasthan, Gujarat and even parts of Madhya Pradesh threatens to amplify into an agrarian disaster.
  • The desert locust, as a species, is the bane of agriculture. Monitoring and tackling periodic outbreaks of the marauding insects are among the objectives of the Locust Warning Organization (LWO) in Jodhpur. There were 13 locust upsurges from 1964 to 1997, and after 2010 there was “no large-scale breeding” reported.
  • Once a significant outbreak starts, it lasts for about two years, and then there is a quietus for about eight years.
  • LWO officials say that the swarm building up is potentially the “worst in decades”


  • Locusts are a group of short-horned grasshoppers that multiply in numbers as they migrate long distances in destructive swarms.
  • Locusts need moist, sandy soil in which they lay eggs and fresh vegetation for hoppers to grow into adults.
  • A good monsoon is, therefore, always cause for concern to locust authorities and farmers.
  • Under suitable conditions, they start to breed abundantly, and become nomadic (loosely described as migratory) when their populations become dense enough.

Difference between locusts and grasshoppers:

  • Locusts are part of a large group of insects commonly called grasshoppers which have big hind legs for jumping. Locusts belong to the family called Acrididae.
  • Locusts differ from grasshoppers in that they have the ability to change their behavior and habits and can migrate over large distances.

Species of locusts:

There are 10 important species of locusts in the world:

  • The Desert Locust, the Bombay Locust, the Migratory Locust, the Italian Locust, the Moroccan Locust, the Red Locust, the Brown Locust, the South American Locust, the Australian Locust & the Tree Locust.
  • Only four types of locusts in India-
    • Desert locust (Schistocerca gregaria),
    • Migratory locust (Locusta migratoria)
    • Bombay Locust (Nomadacris succincta)
    • Tree locust (Anacridium sp.) are reported.

India is most at risk of a swarm invasion just before the onset of the monsoon.

  • The swarms usually originate in the Arabian Peninsula and the Horn of Africa.

How fast can Desert Locusts migrate?

  • Desert Locusts usually fly with the wind at a speed of about 16-19 km/h depending on the wind. Swarms can travel about 5-130 km or more in a day.
  • Locusts can stay in the air for long periods of time. For example, locusts regularly cross the Red Sea, a distance of 300 km.

Are they harmful?

Locusts do not attack people or animals. There is no evidence that suggests that locusts carry diseases that could harm humans.

What Economic Impact they can cause?

  • The swarms devour leaves, flowers, fruits, seeds, bark and growing points, and also destroy plants by their sheer weight as they descend on them in massive numbers.
  • The adults are powerful fliers; they can travel great distances, consuming most of the green vegetation wherever the swarm settles.
  • Adult locusts can eat their own weight every day and a swarm can consume vast quantities of food. They thus, pose a threat to human food security.


  • India has a locust control and research scheme that is being implemented through the Locust Warning Organisation (LWO),established in 1939 and amalgamated in 1946 with the Directorate of Plant Protection Quarantine and Storage (PPQS) of the Ministry of Agriculture.
  • The LWO’s responsibility is monitoring and control of the locust situation in Scheduled Desert Areas, mainly in Rajasthan and Gujarat, and partly in Punjab and Haryana.

Control measures of locusts:

  • Mechanical methods – digging trenches, beating and burning
  • Baiting – scattering locust food impregnated with insecticide
  • Dusting – applying a fine dust impregnated with insecticide
  • Spraying liquid insecticides

Can locusts be controlled?

At present, the primary method of controlling Desert Locust swarms is with mainly organophosphate chemicals 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 knapsack and hand-held sprayers.

Other measures:

  • The spray of high-intensity Malathion insecticidehelps in killing them.
  • The government also plans to deploy drones for spraying pesticides.

Are there any non-chemical ways to kill locusts?

  • Extensive research is in progress on biological control and other means of non-chemical control of locusts.
  • Thus far, control by natural predators and parasites is limited since locusts can quickly migrate away from most natural enemies.

What is the relationship between locusts and climate change?

  • During quiet periods—known as recessions—desert locusts are usually restricted to the semi-arid and arid deserts of Africa, the Near East and South-West Asia that receive less than 200 mm of rain annually.

In normal conditions, locust numbers decrease either by natural mortality or through migration.

However, the last five years have been hotter than any other since the industrial revolution, and since 2009. Studies have linked a hotter climate to more damaging locust swarms.

Wet weather also favours multiplication of locusts. Widespread, above average rain that pounded the Horn of Africa from October to December 2019 were up to 400 per cent above the normal rainfall amount.

These abnormal rains were caused by the Indian Ocean dipole, a phenomenon accentuated by climate change

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 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.

Issues and Challenges:

  • As per FAO’s Locust Status Update, the current situation remains extremely alarming in East Africa where it is an unprecedented threat to food security and livelihoods.
  • New swarms will migrate to the summer breeding areas along both sides of the Indo-Pakistan border as well as to Sudan and West Africa.
  • Good rains are predicted along the Indo-Pakistan border that would allow egg-laying to occur.
  • This year, the locusts are immature and have crossed the India-Pakistan border soon after their birth.
  • The U.N. Food and Agriculture Organisation has warned of more attacks of locusts along both sides of the India-Pakistan border.
  • A bigger challenge is likely to emerge when the swarms flying over 20 districts in Rajasthan start breeding.
  • The locusts will start laying eggs after the onset of monsoon and continue breeding for two more months, with new insects being born during the growth phase of the Kharif crops.

Steps taken by Government of India:

  • Locust Circle Offices (LCO) are conducting survey & control operations in close coordination with the District Administration and agriculture field machinery of the affected States.
  • Advisories have been issued to the States of Rajasthan, Gujarat, Haryana and Punjab regarding the locust attack and necessary measures to be taken for effective control, and pesticides that are to be used for effective locust control in the cropped area.
  • Currently, Locust Control Offices have 21 Micronair and 26 Ulvamast (47 spray equipment) which are being utilized for locust control.
  • e-Tender has been invited for the empanelling agencies to provide services of drones for aerial spraying of insecticides for effective control over tall trees and inaccessible areas.

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