By: Sanjenbam Jugeshwor Singh
Locusts is a polyphagous feeders, which attacks in swarms and causes extensive damage to crops. These locusts can change their DNA according to prevailing environmental situation. In the season of availability of adequate food, the locusts multiplies their progeny faster from eggs to nymphs and adults. Due to its ability to change itself continuously to the prevailing environmental conditions, the control of locusts becomes difficult. Locust can assess the location of crops at harvest stage and fly as a swarm in the direction of the wind and cause severe damage to crops. A desert locust swarm of one square kilometer has about 4 crore locusts which can eat and destroy crops of about 80,500 Kgs overnight according to the experts of FAO. The insects not only causes immense damages to crops on farmland by ravaging leaves, flowers and fruits but they also destroy plants just by their weights as they come in massive numbers. Even a small swarm of locust engulfing an area of 1 sq.km devours food in a day that can feed as many as 40,000 people as reported by FAO. An outbreak usually occurs within an area of 5000 sq.km in one part of the country. If an outbreak or contemporaneous are not controlled and if widespread or usually heavy rainfall in adjacent areas, several successive seasons of breeding can occur, causing further hopper band and adult swarm formation called an upsurge. This can affect an entire region.
Parts of India are experiencing the worst locust invasion the country has been for 25 years. Skies above large part of North India have darkened during the day due to millions of locusts. Rajasthan is the worst affected state but Madhya Pradesh, Gujarat and Punjab have also experienced damaging swarms. A swarm of locust species have attacked banana, rubber plantation dominated districts of Tamil Nadu- causing concern among farmers over the possible destruction of their crops. Farmers in Poovankodu and Viyanur in Kanyakumari district bordering Kerala have claimed that the locust have ravaged the banana and rubber crops to a large extent. India is gearing up for what could be one of its worst locust invasion in decades. Outbreak of the insects attack have been reported from Gujarat, Rajasthan, Maharashtra, Madhya Pradesh, Punjab, Haryana and Utter Pradesh. Garhwa,a district bordering Uttar Pradesh and Chhattisgarh has been put on high alert on Saturday the 30th May 2020 for locust attack.The swarms were last spotted 200km from the district.The swarm reached as far as Jhansi in Uttar Pradesh making it possible for them to enter Jharkhand through Garhwa. On Thursday, May 28, the Delhi government issued an advisory to farmers to spray pesticides and keep a possible attack at bay. Last year, Gujarat and Rajasthan had reported infestations. But it could be worse this year because of a chains of climate events, administrative laxity in several countries and the difficult circumstances brought on by the COVID-19 pandemic. Experts have warned of huge crop losses if the swarms are not stopped by June when the monsoon will lead to a new season of sowing rice, sugar cane, cotton and other crops.
A pattern of warming in the Indian Ocean may be a trigger. A phenomenon called the Indian Ocean Dipole, in which the western and eastern part of the ocean, warm differently tend to have an outsized impact in bringing excessive rains to India and west Asia. A positive, dipole is when the western part is hotter by a degree or more than the eastern. Last year saw one of the strongest positive dipoles in the Indian Ocean neighborhood which brought on a difference of more than two degrees. The Indian Ocean Dipole was so strong that it over-rode- concerns of a draught in India last June and brought torrential rainfall – the most India has seen in decades. It also lasted nearly one month more than what is normal. This 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 the formation of several locusts swarms. While this dipole was beginning to take shape by late 2018 and locust outbreak were growing in Africa, it increased last year. Due to favorable winds, it helped swarms to fly and breed in traditional grounds in Iran, Afghanistan, Pakistan and India. The Food & Agriculture Organization (FAO) a specialized agency of the United Nations has been sending alerts on developing swarms. Somalia announced a national state of emergency due to the locusts’ outbreak in February 2020 while Pakistan declared a national emergency for the second time this year in April. The unusually mild summer this year, which saw several bouts of rainfall over north and western India from March to May also helped the insects breed. The normal locusts season in India spans June-November and coincides with the Khariff season. So far swarms have been re-landed in nearby 50,000 hectares in Rajasthan and Madhya Pradesh and if they continue to thrive as the monsoon arrives, it could cause serious agricultural damage.
In India, existing groups of swarms have continued to move east and to the central states of Madhya Pradesh and Maharashtra. Much of these movement were associated with strong westerly winds of cyclone “Amphan”. Several successive waves of invasion are likely until July in Rajasthan, with eastward surges across northern India as far as Bihar and Odisha followed by westward movement and a return to Rajasthan on the changing winds associated with monsoon. These movements will ceases as swarms begin to become less mobile. The swarms are less likely to reach Nepal and Bangladesh and south India according to experts.But another stream passing over the Indian Ocean can directly attack farms in Peninsular India and then head towards Bangladesh.The long gap between the last and present locust attack in India has had a consequence. The destructive power of a typical locust swarm, which can vary from less than 1 sq.km to several hundred sq.km is enormous as per the websites of FAO. The locust attack which could undermine food security in Afro-Asian region, follows the economic devastation and savaging of income by COVID-19 pandemic. The director –general of Indian Council of Agricultural Research (ICAR), admitted that there hasn’t been much “systematic research” on desert locust since the 1990s and the current invasion is a wake-up-call to revive the program. This is indeed a wake-up-call. The earth has entered a period of hydrological, climatological and biological change that differs from previous episodes. Therefore it is important that India puts in enough funds to predict the course of the present global environmental changes to understand the sources, consequences and formulate national response of locusts’ invasion.
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