Locust Invasion: Ready to Face?

World is currently facing a pandemic in the form of Covid-19, and is unable to recover from its implications on health and economy. However, Covid-19 is not the only challenge we are dealing with; many countries (especially African and Asian countries) are engulfed with locust swarms that may pave the way for human starvation if not managed properly. The United Nations Food and Agriculture Organization (FAO) has warned member countries regarding the locust threat and has reported that locust invasion may affect the livelihood of 10% of the world’s population. As the challenge is looming, public in general and farmers in particular need to understand locust invasion and its implications.

Locust: A special kind of grasshopper

The unusual swarming behavior of locusts has been reported from ancient Egypt, and reports of their damage to agricultural crops is a matter of historic records. Locust are simply transformed version of grasshoppers and are highly active in their ‘gregarious phase’. Entomologists explain that there are hundreds of species of grasshoppers, but only few species are considered as locust when they show certain morphological and behavioral changes. It is believed that locust form of grasshopper develops when there is abundance of rainfall and moisture in the environment, which is also known as ‘phenotypic plasticity’ whereby dramatic alterations occur in locust in response to environmental conditions.

Unpredictable environment acts as a trigger

Although locust swarm is a natural phenomenon and can’t cause major damage at low scale, nevertheless, uncontrolled locust invasion can have major implications. The research regarding their cause of development and how they show mass scale invasion is still in its infancy. However, unpredictable environmental conditions, especially massive rainfall and humidity acts as a trigger for the development of these nuisance insects. Entomologists suggest that during dry seasons, normal locust assemble together and during this period of crowding certain secretions (serotonin) are released from central nervous system that make normal locust more sociable, voracious and agile. United Nations Environmental Program (UNEP) experts have recently revealed that increased level of temperature in last five years, since the industrial revolution, can be linked to the emergence of deadly locust species that has a potential to damage agricultural crops.

Food security at stake

It is has been estimated that medium sized locust swarm can eat as much food as 35, 000 people can take up during a single day.  According to the FAO, “a swarm of just 1 square kilometer — again, about a third of a square mile — can consume as much food as would be eaten by 35,000 people (or six elephants) in a single day”. However, these ravenous creatures can pose great damage if not controlled at proper time. As per Rick Overson (Expert on Locust Initiative in Arizona State University’s Global), uncontrolled locust swarm can destroy agricultural crops by 50%-80%. Locust plague has already damaged agricultural crops in African and Asian countries and is expected to affect 25 million people in the coming months. The devastating locust invasion has impacted the food security of 17 million people of Yemen, a war ravaged country. Initial figures from India suggest modest damage to the agriculture crops, although government is still engaged in surveys to know actual figures of the damage. Fortunately, locust swarm has not reached to North West Himalayan (Kashmir) region yet. However, government and public need to keep vigil in the coming months as new wave of this insect plague has not been ruled out.

Management of locust plague

Control measures against locust swarm are difficult as they are continuously on the run, and are migratory. However, methods have been developed recently to mitigate the locust swarm across the globe. Some of the management procedures which are being followed are:

  • Survey and track locust migration pattern is the foremost management procedure that gives early clue about their migratory route and other details
  • Most effective method of control is to use aerial sprays of pesticides during the period of locust in a particular area. Timing of the spray is very important and need to be performed as per standard protocol.
  • New emerging technology holds great promise for the mitigation of this invasive insect. Recently, National Oceanic and Atmospheric Administration (NOAA) took an initiative with United Nations to use previous technology to predict the migration routes of locust which was previously used to track smoke plumes from fires.
  • Biological control methods have great potential to tackle locust problem without damaging environment and is being researched across the globe. China has used Ducks as a biological tool to curb invasion of locust.
  • In Pakistan (Okra Distt. of Punjab), sustainable and environmentally feasible solution has been implemented in which locusts are being trapped, and are turned into high-protein chicken feed by industrial mills. The farmers get two way benefit: getting rid of locust pests and also earn money.

However, there are some hindrances:

  • a sustained level of funding, accompanied by a political will, during pandemics (Covid-19) is a difficult task
  • There is danger of using chemicals as it may have negative impact on biodiversity and human health. If chemicals are used unabated, then we may need another campaign of Rachael Carlson to kick-start environment movement against chemical industry.

Dr. Ummer Rashid Zargar is Assistant Professor, Department of Zoology, Govt. Degree College Anantnag,