Brain Booster for UPSC & State PCS Examination
Topic: Locust Control
Why in News?
- An invasion by desert locusts has hit large swathes of India in the middle of the coronavirus pandemic.
- Large and aggressive swarms of these crop-devouring short-horned insects have invaded more than two dozen districts of desert areas of western India.
- They entered several districts of Rajasthan via Pakistan's Sindh province.
Agrarian Disaster
- This locust attack has affected about 90,000 hectares across 20 districts in Rajasthan. Favourable rain-bearing winds aided their transport towards India. This quickly growing swarm is now threatening to amplify into an agrarian disaster.
- Since the Rabi crop harvesting is over and the Kharif sowing season is yet to begin, they were unable to find any vegetation.
- According to the Food and Agriculture Organisation (FAO), the destructive power of a typical locust swarm can be enormous. The size of these swarms can vary - from less than one square kilometre to several hundred square kilometres.
- If not controlled, desert locusts can damage food supplies and cause famine. Some 45 million sq km of land in 90 countries are potentially prone or under the threat of invasion by the desert locust, according to the FAO.
Mitigating the Disaster
- The locust problem is not confined to India alone, but most of Africa, West Asia, Iran and even parts of Australia.
- Historically, locust control has involved spraying of organo-phospate pesticides on the night resting places of the locusts.
- The Indian Institute of Sugarcane Research, Lucknow, advised farmers to spray chemicals like lambdacyhalothirn, deltamethrin, fipronil, chlorpyriphos, or malathion to control the swarms.
- However, the Centre had banned the use of chlorpyriphos and deltamethrin. Malathion is also included in the list of banned chemicals but has been subsequently al-lowed for locust control.
- Special mounted guns are used to spray the chemicals on the resting places.
- Drones are also being used this year.
- In Uttar Pradesh, local villagers have been asked to make noise by beating 'thalis' and bursting crackers.
About Desert Locusts
- Desert locusts (Schistocerca gregaria), which belong to the family of grasshoppers, normally live and breed in semi-arid/desert regions. For laying eggs, they require bare ground, which is rarely found in areas with dense vegetation. So, they are more likely to breed in Rajasthan than in the Indo-Gangetic plains or Godavari and Cauvery delta.
- While green vegetation is good for hopper development – the stage between the nymph that has hatched and before its turning into a winged adult moth – such cover isn't widespread enough in deserts to allow growth of large locust populations.
- Locusts aren't dangerous as long as they are individual hoppers/moths or small isolated groups of insects, in what is called the “solitary phase”. It is when their population grows to large numbers – the resultant crowding induces behavioral changes and transformation from the “solitary” to “gregarious” phase – that they start forming swarms.
- A single swarm contains up to 40-80 million adults in one square km and these can travel up to 150 km in one day.
- The main locust breeding areas in the Horn of Africa, Yemen, Oman, Southern Iran and Pakistan's Baluchistan and Khyber Pakhtunkhwa provinces.