Desert locusts are known for causing massive destruction of food crops, greenery and plants. They reproduce in lakhs and form swarms in search of food. They travel hundreds of miles with their strong wings and legs without taking any break. According to FAO, a one square kilometre swarm of locusts, with about 40 million locusts, can in a day eat as much food as 35,000 people, assuming that each individual consumes 2.3 kg of food per day.
Locusts are about 2 inches (5 centimeters) long in size and have short, thick antennas. Due to climatic changes, they reproduce so quickly in large numbers and become crowd. They behave differently in crowds and start forming into swarms. Without any break, they fly for days or weeks over thousands of miles. When they finally stop, each locust can intake more food than its body weight. This can destroy farm fields very quickly and leave people to starve for food to eat and can lead to famine.
The desert locust is an international pest affecting about 60 countries, mainly India, Pakistan, Afghanistan, Arabia, Persia, Iraq and Africa. It is known to migrate in swarms from one country to another leaving behind famine. Adult locust swarms can fly up to 150 km (93 miles) a day with the wind and adult insects can consume roughly their own weight of fresh food per day. A very small swarm eats about as much food as 35,000 people eat in a day.
During 2019-20, India witnessed a massive locust attack which was successfully controlled. Starting from 11th April, 2020 till 25thAugust, 2020, control operations have been done in 2,79,066 hectares area in States of Rajasthan, Madhya Pradesh, Punjab, Gujarat, Uttar Pradesh and Haryana by Locust Circle Offices (LCOs). Till 25thAugust, 2020, control operations have been done in 2,87,374 hectares area in States of Rajasthan, Madhya Pradesh, Punjab, Gujarat, Uttar Pradesh, Maharashtra, Chhattisgarh, Haryana, Uttarakhand and Bihar by State Governments.
Usually, the locust swarms enter the Scheduled Desert Area of India through Pakistan for summer breeding in the month of June/July with the advent of monsoon. This year, however the incursions of locust hoppers and pink swarms have been reported much earlier because of presence of residual population of Locusts in Pakistan (uncontrolled from last season). Since 11th April 2020, locust hoppers and from 30th April, 2020, the incursion of pink immature adults has been reported in bordering districts of Rajasthan and Punjab. Pink immature adults fly high and cover long distances during day hours from one place to another along with the westerly winds coming from the Pakistan side. Most of these pink immature adults settle on the trees during night and mostly fly during day.
During 2019-2020, in Gujarat, locusts attacked in December and damaged mainly rapeseed and cumin seed planted in about 17,000 hectares. In the neighbouring Rajasthan, 3,60,000 hectares came under the attack. The migratory pest later entered Punjab, Haryana and Madhya Pradesh, threatening major damage to standing cotton crop and vegetables.
After crop destruction in 18 districts of Rajasthan and a dozen districts of Madhya Pradesh, an army of desert locusts reached Jhansi in Uttar Pradesh, prompting the government to declare a state-wide alert. In Uttar Pradesh, locusts are feared to affect 17 districts - Agra, Aligarh, Mathura, Bulandshahr, Hathras, Etah, Firozabad, Mainpuri, Etawah, Farrukhabad, Auraiya, Jalaun, Kanpur, Jhansi, Mahoba, Hamirpur and Lalitpur. However, due to change in wind direction, movement of swarms changed its route to Pingal.
As on 21 June 2020, swarms of immature pink locusts with intermittent population of maturing yellow adults were active in Jaisalmer, Barmer, Jodhpur, Bikaner, Sri Ganganagar, Jaipur, Nagaur, and Ajmer districts of Rajasthan, Panna district of Madhya Pradesh and Lalitpur district of Uttar Pradesh.
As on 27th July 2020, swarms of immature pink locusts, adult yellow locusts and/or hoppers are active in Jaisalmer, Barmer, Jodhpur, Bikaner, Churu, Nagaur, Sriganganagar, Jhunjhunu, Hanumangarh and Sriganganagar of Rajasthan and 01 place in Kutch district of Gujarat. No significant crop losses have been reported in the States of Gujarat, Uttar Pradesh, Madhya Pradesh, Maharashtra, Chhattisgarh, Bihar and Haryana. However, some minor crop losses have been reported in some districts of Rajasthan.
As on 9th August 2020, hoppers and/or some scattered locust adults were active in Barmer, Jodhpur, Bikaner, Nagaur, Churu, Hanumangarh and Sriganganagar of Rajasthan and in Kutch district of Gujarat. As on 19th August 2020, hoppers were active in Jaisalmer, Barmer, Bikaner, Churu and Hanumangarh of Rajasthan and Kutch district of Gujarat. As on August 26, 2020, no locust adults or hoppers were spotted in any of the affected areas
As per the Food and Agriculture Organization’s Locust Status Update of 24 Aug., 2020, the risk of swarm migration to the Indo-Pakistan summer breeding area has nearly subsided. Weekly virtual meeting on Desert Locust of South-West Asian countries (Afghanistan, India, Iran and Pakistan) is being organized by FAO. 23 virtual meetings of the technical officers of South West Asian countries have taken place so far.
Heavy rains create favourable breeding conditions for locusts along the India-Pakistan border. If allowed to breed unchecked in favourable conditions, locusts can form huge swarms that can strip trees and crops over vast areas. Once a swarm has developed, it is almost impossible to control.
In India more than 2 lakh square kilometers area comes under Scheduled Desert Area. Locust Warning Organization and 10 Locust Circle Offices (LCO) of Government of India are situated in Rajasthan (Jaisalmer, Bikaner, Phalodi, Barmer, Jalore, Churu, Nagaur, Suratgarh) and Gujarat (Palanpur and Bhuj) are responsible for monitoring, survey and control of Desert Locust in Scheduled Desert Area in coordination with State Governments.
The chief aim of locust control is to destroy the locust in all its’ stages.
Authors : Dr. Usha Kalidindi Principal Scientist, FHT, ICAR-IARI, New Delhi -110012 and Aruna Gali.