Many know that desert locusts, also known as Schistocerca Gregaria, normally live and breed in desert regions. It is during this time, they require the bare ground to lay eggs. With this keeping in mind, these locusts can breed in Rajasthan but not in the Indo-Gangetic plains.
As for how the desert lands are required for the locusts, green vegetation is also required for the swarm’s development. As individuals, or in small isolated groups, these locusts are not very dangerous. But when they grow into large populations their behavior changes, they transform from ‘solitary phase’ into ‘gregarious phase’. It is estimated that a single swarm can contain 40 to 80 million adults in one square km, and these can travel up to 150 km a day.
Generally, these locusts breed in the dry areas around Ethiopia, Somalia, Eritrea along the eastern coast of Africa, a region known as the Horn of Africa. Similarly, other breeding grounds are Asian regions in Yemen, Oman, southern Iran, and Pakistan’s Balochistan and Khyber Pakhtunkhwa provinces.
Recently, the Locust Warning Organisation, a unit under the Agriculture Ministry, spotted these and warned of their presence at Jaisalmer and Suratgarh in Rajasthan, and Fazilka in Punjab near the India-Pakistan border.
Why are these locusts arriving early when July-October is the normal time?
It is reportedly said that unusual cyclonic storms of 2018 in the Arabian Sea are the key reason behind these locusts’ early arrival. Cyclone Mekunu and Luban had struck Oman and Yemen respectively that year. Also, heavy rains had transformed uninhabited desert tracts into a large lake where a swarm of locusts could breed. If this issue is left attended, a single swarm can increase 20 times of its original population in the first generation itself. Once they start breeding, the locust swarm movement will cease or slow. Also, the breeding will happen mainly in Rajasthan.
What are the damages they have caused so far?
Since the rabi crop has already been harvested, and farmers are yet to start Kharif sowings. However, the UN Food and Agriculture Organization (FAO) has predicted: “several successive waves of invasions until July in Rajasthan with eastward surges across northern India right up to Bihar and Odisha”. After July, there would be westward movements of the swarms that would return to Rajasthan.
How can the population of these pests be controlled?
Locust control has involved the spraying of organic-phosphate pesticides on the night resting places of the locusts. Recently, the Indian Institute of Sugarcane Research, Lucknow, advised farmers to spray chemicals like lambda-cyhalothrin, deltamethrin, fipronil, chlorpyriphos, or malathion to bring things under control. However, On May 14, the Centre had banned the use of chlorpyriphos and deltamethrin. Malathion is also included in the list of banned chemicals but has been subsequently allowed for locust control.
Spraying neem oil on standing crops to be effective in eliminating locust attack:
As parts of Maharashtra and other states face attacks from locusts, which destroy crops and vegetation, an agriculture university has suggested a slew of measures like destroying their eggs and spraying neem oil on crops to tackle the threat from the migratory pests. Swarms of crop-eating locusts have spread across Madhya Pradesh, Rajasthan, Uttar Pradesh, and Maharashtra. The fast-moving insects entered parts of Vidarbha in eastern Maharashtra earlier this week.
Destroying their eggs, digging trenches of a specific size, and spraying neem oil on standing crops are some of the effective methods to tackle the menace caused by locusts. Female locusts lay 50 to 100 eggs in moist sandy land. The hatching period of these eggs depends on the environment and may stretch from two to four weeks. Larvae cannot fly immediately when they come out.
According to university experts, larvae, when they grow and start flying in groups, can destroy leaves, branches, flowers and seeds. Adult locusts can eat food equivalent to their weight and can fly with a speed ranging from 12 to 16 km per hour. “If a swarm of locusts is in one square km area, their weight can be up to 3,000 quintals. Their flocks can be neutralised during night time (which is their resting time) with the help of smoke.” the university said. Spraying 2.5 litres of neem oil per hectare has also proved effective in controlling swarms of locusts, it said.
Locust control operations have been undertaken every day in the morning hours with the help of control spray vehicles, tractor mounted sprayers and fire brigade vehicles under the supervision of concerned district authorities and officials of the State Agriculture Department. The Rajasthan government has deployed 778 tractors and 50 fire brigade vehicles, Madhya Pradesh – 72 tractors and 38 fire brigade vehicles, Uttar Pradesh deployed 6 tractors and Punjab deployed 50 tractors and 6 fire brigade vehicles for locust control. Presently, pink swarms of immature adults are being reported in India which is very active and mobile and it is difficult to control them in one place. It takes at least 4 to 5 days of control at different locations for the complete elimination of the locust population in one flock.