May 27 (IndiaToday) – to feed and to breed is life. Rest is civilisation. Desert locusts are feeding and breeding in agricultural fields, the basis of human civilisation. At least five states in India are currently facing the grave threat of wide-scale crop destruction due to an unusual locust attack.
Desert locusts are grasshoppers. But they differ from regular grasshoppers in being short-horned and highly migratory in nature. Their life span is just 90 days.
Each flock of desert locusts is called a swarm. But the locusts have not reached adulthood and are in the nymphal stage of life, the group is called band. Around 80 lakh locusts can be in a swarm. They stay together, they feed together and they breed together.
AT OUTSET, KNOW YOUR ENEMY: LOCUSTS
Desert locusts are voracious eaters. They eat food equal to their body weight every day. A single swarm of locusts can finish food for some 2,500 people in a day.
This is what they are doing in the fields of Rajasthan, Gujarat, Maharashtra, Madhya Pradesh, Punjab and also Uttar Pradesh.
As they feed, they breed, with very high fertility in geometrical pattern. In just three breeding seasons, locusts increase their population size by 16,000 times.
Their biological makeup has strong radars for moisture and greenery, which they chase all their lives. They are highly adaptive and change their behaviour according to weather and region.
When they migrate, they raid green crops. Their migration follows the path of the prevailing wind. They eat green and leafy plants.
HOW THEY REACHED INDIA?
It is a long story. Let us first focus on the origin.
Desert locusts can be considered to be natives of Saudi Arabia or the Arabian Peninsula. Following the monsoon winds, they arrive in India – in Rajasthan and Gujarat particularly – every year. An average of 10 locust attacks or swarms are seen in India in a normal year.
However, something changed over the past two years beginning in 2018. Saudi Arabia had unusually excessive rain in 2018 due to two cyclones – Mekunu in May and Luban in October.
The Arabian Peninsula developed lakes in deserts such as Rub’ al-Khali – literally meaning the Empty Quarters – in one of the driest and most uninhabited regions in the world. This was a first in some 20 years.
But why was the Arabian Peninsula hit by two cyclones in a year? Experts have pinned it on to climate change that has seen the Arabian Sea have three cyclones a year in recent times compared to one in every five years or so.
CLIMATE CHANGE TO GLOBAL SWARMING
Cyclones did two things to cause the locust phenomenon that many experts have dubbed as global swarming. The desert locusts got favourable conditions for food and reproduction in their own backyard. Their numbers swelled enormously. The region could not support such a population of locusts in 2018-19.
Secondly, cyclones altered wind pattern temporarily. The swarms of locusts, unable to stay in the deserts moved southward to Yemen and entered Africa creating a famine-like situation. They have impacted almost the entire eastern Africa and parts of North Africa.
Northward swarms crossed the Red Sea over to Iran and Pakistan. They were helped by abnormally heavy rains along the Red Sea coasts. Moisture and greenery, they got all that they look for.
By April 2019, locusts had destroyed an estimated 40 per cent crops in Pakistan, creating a serious food security risk.
Now, it was time for locusts to hit India, which too had a rather abnormal monsoon onset. Western Rajasthan got monsoon about six weeks earlier than normal. By mid- had monsoon had arrived in Rajasthan. The usual date is July 1.
Monsoon brought greenery. Locusts crossed the borders and attacked fields in India. Under normal weather conditions, the locusts swarms come to India in July, breed for one season and leave for Pakistan-Iran in October.
But an early monsoon brought them earlier. Then monsoon had an extended spell in Rajasthan last year – till late November. This means, for a 90-day life span, the locusts got to breed in India three times – in June, September and December when moisture was still there. This also meant they were 16,000 times in number than what could have been the norm.
The desert locusts rest in Iranian region during the winters before following the moist winds over to Arabian Peninsula or a more favourable region.
WHY THIS YEAR AGAIN
South-east Iran and south-west Pakistan (Iran-Pakistan region) received too much rain in January this year. In fact, south-east Iran got its annual average of rain in the first week of January itself this year. This drew swarms from the deserts to Iran-Pakistan.
What has also happened is that the early 2020 summer in India has been unusual, the MeT department has already said this. It said India has received “excessive rain”, 25 per cent more than the normal between March 1 and May 11.
In Rajasthan, heatwaves were not building. In fact, it received rainfall due to western disturbances – the cyclones originating in the Mediterranean. This explains why desert locusts have come to India early again. The exponential population growth last year has just aggravated the problems for farmers, the governments and threatens food situation in the country.
WHAT HAS BEEN THE RESPONSE?
The central government agency, Locust Watch Centre keeps an eye on their movement to warn farmers and take appropriate measures to minimise crop damage due to locust attacks. But there have been reports that these centres have been facing a resource crunch for years.
While some reports said India had around 200 swarm attacks in 2019, the government appeared to have no official data about crop loss due to locusts.
The swarming problem was raised in the Lok Sabha last year in July, when Union Agriculture Minister Narendra Singh Tomar had said the locusts were sighted in Rajasthan and Gujarat but there was no crop damage.
The local governments and the Locust Watch Centres seem to have got in to action in November last year when they mobilised farmers, advising them how to tackle the swarms. But it was too late. The locusts were to leave a month later and come back early this year.
PRESCRIPTION TO MANAGE LOCUSTS
Desert locusts travel and eat only during day time. This means they are easy prey during nights.
The Food and Agriculture Organisation (FAO) has laid out a standard operating procedure to deal with locust menace. Sandy areas that have green vegetation are to be monitored constantly to see if locusts are present.
Desert areas receiving rainfall are to be surveyed for live locusts or their eggs. Recommended pesticides are to be used to stop their breeding.
Areas, where farmers have recently reported sighting of locusts, are to be surveyed and sanitized.
Special attention is to be paid in areas where day temperature ranges between 20 degree Celsius and 38 degree Celsius because if these areas have moisture or receive rain, the desert locusts are likely to swarm in.
Indian agencies, with evidence on hand, must have failed somewhere in following the SOP prescribed by the FAO. Now, it is the time to fire fight.