The Voracious Appetite of Locusts

Threatening Food Scarcity and Loss of Livelihood

The Voracious Appetite of Locusts
The Voracious Appetite of Locusts

While gazing through the gloomy and bright phases of history, the year 2020 will definitely be underlined. Not because tens of thousands died in the pandemic but because nature showed its fury to the fullest, warnings of which it had shown over the years. While the world is still battling the pandemic, swarms of locusts attacked east Africa, Iran, Afghanistan, Pakistan and India multiplying the woes many folds for these countries. The oncoming food crisis built by the COVID-19 pandemic, will have the locust attack as a trigger point.


In May 2020, a massive swarm of locust entered India via Pakistan travelling all the way from East Africa. Locusts are collection of insects belonging to one of the 12 species of short-horned grasshoppers, though they differ in characteristics. According to the FAO, a swarm of 1 sq. Km can contain upto 40-50 million insects and can consume food of upto 35,000 people in a day. This is the second infestation since last year and the reasons have been attributed to climatic factors.

The article discusses the recent infestation and the climatic factors that are responsible. Further, a brief history is presented along with damages and mitigating measures taken in India.

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Coronavirus, cyclone Amphan, Vizag gas leak and similar disastrous events have wreaked havoc in India in the last 6 months. The struggle and pain through these events had hardly subsided when swarms of desert locust entered Western India from Pakistan destroying crops in Rajasthan, Uttar Pradesh and Madhya Pradesh, amplifying into an agrarian disaster. Locusts, the bane of food production is not a new phenomenon but a regular one, however, their atrocities usually ended by November. This recent attack is the second attack, the first being in 2019 which extended till February this year. Scientists have attributed the onslaught and the lengthy stay of these little devils due to climate change.

The Hungry Little Devils

By early summer huge swarm of locust invaded vast swathes of land in India, which is now being termed as the worst attack in the last 3 decades. Madhya Pradesh, Rajasthan, Punjab and Gujarat were the first and worst affected states. Of 33 districts 16 are battling the pests in Rajasthan, while in Madhya Pradesh the Nimar-Malwa region has had the worst attack in the last 27 years. As of this week, the swarm has reached Uttar Pradesh and continues its eastward move.

What are locust? Info 2
What are locust?

According to United Nation’s Food and Agriculture Organization (FAO), ‘the destructive power of a typical locust swarm can be enormous’. The size of the swarm vary from less than 1square kilometer to several 100 square kilometer.  A swarm size that of Paris can consume the same amount of food as half the population of France in a day (if one person eats approximately 2.3 kg food a day).

The desert locust are one of the 12 species of short-horned grasshoppers, which have the ability to change behaviour, habits and migrate over long distances. These grasshoppers are solitary creatures, but driven by food scarcity, start gathering while foraging for food. As this population increases, the grasshoppers start becoming ‘gregarious’. ‘Gregariousness’ is the tendency of animals to form social groups to hunt or eat together. The gregarious tendency induces coordinated movements and swarms are formed. Gregarious grasshoppers are called locusts.

It is believed that the locusts become gregarious when they constantly touch each other’s hind legs. This release large amounts of serotonin a ‘happy hormone’. The process of gregariousness also induces changes in colour, turning them from green to a shade of yellow-brown and strengthening their muscles.

The life span of these insects is 3 to5 months, depending on the climate. Female locusts can lay eggs at least thrice in their lifetime, at intervals of 6-11 days. The population have the capacity to multiply up to 20-fold in just three months. Certain environmental conditions like prolonged monsoon and heavy cyclones make them reproduce faster. They can eat upto their own bodyweight in food and fly over 150km in a day, riding the wind to ease the strain of long flights. Desert locusts are known to have crossed the Red Sea, over 300 km. In 1988 it is believed that a swarm crossed the Atlantic Ocean, over 5000 km, travelling from West Africa to the Caribbean.

Swarms are of three forms: small pockets confined to certain areas called outbreaks, slightly larger groups, called an upsurge and mega groups, called plague.

A Climate Induced Infestation

As mentioned earlier the current infestation is due to climatic factors. Scientists are speculating that a strong positive ‘Indian Ocean Dipole’ is responsible for the large swarm of locusts invading India. ‘Indian Ocean Dipole’ is the differential warming of Indian Ocean, in the western and eastern parts of the ocean, and brings excessive rains to India and West Asia. Last year, the Indian Ocean Dipole was so strong that it brought torrential rainfall in most parts of India. Extended rainfall continued in several parts of West Asia, Oman, Yemen and in the Horn of Africa- Ethiopia, Somalia, Kenya- so much so that the dry sand became heavily moisture laden, facilitating unprecedented breeding and the rapid growth of  locust which eventually transform into locust swarms.

Reasons for the infestation Info 1
Reasons for the infestation

Another reason is due to monsoon which started 6 weeks ahead of its time in western India, and lasted till November, instead of the usual September/October cycle. Extended rains created breeding conditions and natural vegetation on which locusts feed. According to FAO, the locust movement was helped by strong westerly winds from Cyclone Amphan that hit Eastern India. These movements will cease as swarms begin to breed and become less mobile. The current situation remains “extremely alarming” in East Africa, where Kenya, Ethiopia and Somalia continue to face unprecedented threat to food security and livelihood.

Lastly, experts also attribute the current invasion of locusts to the fact that while rabi crops have been harvested, kharif sowing is yet to begin. Low availability of crops is leading the swarms to devour leaves on trees, and vegetable, fruits and other crops, and move deeper into India in search of fodder.

A History of Damage

Locust attacks have been recorded in ancient Egypt dating back to 2500 BCE. It is even mentioned in The Bible, Quran and several other holy books.  They’ve been recorded in ancient China, Greece, Rome, Syria and other parts of the world. The coincidence of the pandemic and locust attack would seem biblical to the prophets of doom.

Throughout the 19th century, India experienced serious locust attacks. The first measure that was taken was to systematically collect and record data regarding the locust occurrences. The British encouraged entomologists- scientists who study insects –to research locusts with the hope of understanding this phenomenon.

As a result of the 1926-1931/1932 locust outbreak, the Locust Warning and Control Organization (LWO) was established with a station in Karachi. Its main job was to keep out an eye for a specific sub-species of the insects, as it sprang into the region from the Thar desert.

Presently, the LWO has two headquarters: in Faridabad (near New Delhi) for administrative duties. Another one: Jodhpur (Rajasthan) for technical operations, overseen by the Indian Council of Agricultural Research.  The Directorate of Plant Protection, Quarantine and Storage; Ministry of Agriculture and Farmers Welfare, is responsible for monitoring, survey and control of desert locust in Scheduled Desert Areas (mainly Rajasthan and Gujarat). Surveys are done about two weeks after receiving the rain. Though surveys are done throughout the year, the focus is more from May to November, when their activity is considered to be at the peak. Even though India witnessed several locust plagues and upsurges (1812 to 1997), but since December 2011, no locust upsurges have taken place until this year.

In India one of the key ideas during colonial times was to destroy the breeding grounds and locust larvae even before they could fly. Oil-tarred screen known as Cyprus was used to kill locust. The other two popular methods were the net system and the ‘dhotar’ method. The net system involved holding a ‘capricious’ bag and swinging it around fields, trapping young locusts in the process. The ‘dhotar’ method involved using a blanket to trip locusts resting on bushes. Some farmers even changed their cropping patterns.

Damage and Mitigation

According to the Ministry of Agriculture, locust attacks devoured around 3.75 lakh hectares of crops in the 2019-20 cropping season, with a loss of over Rs 100 crore. Since the beginning of May, locusts destroyed over 2 lakh hectares of crops and threaten another 6 lakh hectares of crop. Also due to the low availability of crops in between cropping season, swarms are devouring on trees, and vegetable, fruits and other crops, and moving deeper into India in search of fodder.

The primary method that has resorted to is concentrated doses of organophosphate chemicals sprayed by vehicle-mounted, aerial sprayers along with hand-held sprayers.

Drones have been deployed which can spray pesticide on nearly 2.5-acres within 15 mins.  The three states Rajasthan, Madhya Pradesh and Uttar Pradesh also have used drones, tractors and cars to spray pesticides.  The Union Government arranged for drones, so far 15 sprayers have arrived from UK followed by 45 more. The control work is ongoing in coordination with states and Border Security Force.

Farmers were told to beat steel utensils during late afternoons and evenings and play loud music at night and create wood fire, to ward off locust swarms from farms.

As the current locust swarms have bred and matured in Iran and Pakistan, India offered assistance to both the countries to jointly combat the menace. However, only Iran accepted the offer and the External Affairs Ministry approached state-owned HIL for the manufacture and supply of the pesticide Malathion Technical to Iran.


The pandemic and the locust infestation are actually a hint to take the signals form nature seriously. Political borders may restrict people’s movement but cannot protect from nature’s fury. Experts say that the disastrous events will be frequent as a result of global climate change. So international cooperation is the only solution to these problems, were various organizations and institutions play an important role, to coordinate among member countries.

In this backdrop, India had reached out to Pakistan to counter the locust invasion. India had proposed a trilateral response in partnership with Pakistan and Iran, which was only responded by Iran. Though China is lending a helping hand to Pakistan but that would not be enough.

As there’s a long gap between the last and present locust attacks in India and there hasn’t been much ’systematic research’ on desert locust since the 1990’s, the current invasion is a wakeup call to revive the programme. Also, due to climate change earth’s hydrological, climatological and biological cycles have changed from previous episodes. Therefore, India needs to put enough fund to understand the present global environmental changes to understand the sources, consequences and formulate national responses.


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Climate Change and India


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