Locusts usually solitary, but under certain circumstances they become more abundant and change their behavior and habits, becoming gregarious. No taxonomic distinction made between locust and grasshopper species; the basis for the definition is whether a species forms swarms under intermittently suitable conditions.
These grasshoppers are generally innocuous, their numbers are low, and they do not pose a significant economic threat to agriculture. However, under appropriate conditions of drought followed by rapid vegetation growth, serotonin in their brains triggers a dramatic set of changes: they start to breed abundantly, becoming gregarious and nomadic (loosely described as migratory) when their populations become dense enough.
The desert locust is a species of locust, a swarming short-horned grasshopper in the family Acrididae. It is one of the most devastating migratory pests in the world, and it is highly mobile and feeds on large quantities of any green vegetation, including crops, pasture, and fodder.
A typical swarm can be made up of 150 million locusts per square kilometer and is carried on the wind, up to 150 km in one day. Even a tiny, one-square-kilometer locust swarm can eat the same amount of food in one day as about 35,000 people.
While the start of the year saw COVID-19 send panic across the globe, another crisis was steeping in East Africa. From December 2019 to spring 2020, a plague of Acrididae, the largest the region had seen in generations swept across the region, from the Horn of Africa to the deserts of Kenya, decimating the crops that feed tens of millions of people. Kenya hadn’t faced a plague this severe in over 70 years, and Ethiopia and Somalia not in a quarter of a century.
“We gave Kenya more than 10 weeks of warning, and they responded very quickly. But the magnitude of the problem has overwhelmed national capacity. It was just waves and waves of invasion,” said Keith Cressman, Senior Locust Forecasting Expert at the Food and Agriculture Organisation of the United Nations.
After ravaging crops in several Indian states last year and earlier this year,Acrididae have already hit parts of India this month. Another swarm expected to enter India and Pakistan in June, a top official of the UN’s food and the agricultural agency has warned.
Recent reports mention that hordes have already moved as far inland as Madhya Pradesh, with about 16 districts of Rajasthan affected so far. A report on Friday mentions that the district administration of Agra in Uttar Pradesh has sounded a warning as well.
The desert locust invasion, which poses a significant threat to the livelihoods and food security, is expected to move from East Africa to India and Pakistan next month and could be accompanied by other swarms. The original crowd that came up in 2019 originated in the horn of Africa and had moved eastward.
The first wave of locusts had hit Rajasthan in May last year and had caused damage to crops spread over lakhs of hectares. To know about the benefits of KCC for Indian Farmers click here.
Techniques to control:
Controlling swarm is no easy task. It is a more significant and more difficult task. Species typically live for about ten weeks. Burn green branches to make smoke if you are trying to drive a swarm of locust off your crops. Although this doesn’t always work, some farmers have had success smoking the hordes out. Currently, the most commonly used control is insecticide Sprayed from land or aerial vehicles, whole swarms can target in relatively short periods.
However, this has led to some environmental concerns. One of the most effective ways to avoid the devastating effects of locust plagues is to prevent them from happening in the first place—considerable resources allocated to early warning and preventative control strategies.
short-horned grasshopper monitoring stations collect data on weather, ecological conditions and locust numbers, making forecasts of the timing and location of breeding. Despite these efforts, West Africa faced one of its most massive locust outbreaks in 2003-2005.
Cold, dry conditions in the winter finally allowed control agencies to halt the epidemic at the cost of around $400 million and harvest losses calculated at more than five times that amount. Prevention, then, is likely the best medicine, but this requires keeping a very keen eye out. Remember, it only takes three locusts to make a swarm.