India is witnessing the worst locust invasions in decades. Locust swarms have been reported from Gujarat, Rajasthan, Maharashtra, Madhya Pradesh, Punjab, Haryana and Uttar Pradesh till May 27, 2020.
Past attacks
- According to the Locust Warning Organization (LWO), in Jodhpur, there were 13 locust plagues between 1964 and 1997.
- From 1997 to 2010, there were five outbreaks that were controlled.
- From 2010 to 2018, there were no major swarms or breeding reported.
- In 2019, Gujarat and Rajasthan reported a significant surge in locust infestations
Locust Species in India
- Locusts are grasshopers with short horns and short antenas. They usually fly off together in search of food and to start new colonies.
- The most common locust species found in India are desert locust (schistocerca gregaria), migratory locust (locusta migratoria), Bombay locust (nomadacris succincta) and tree locust (Anacridium sp.).
- It is the desert locust that is found in large numbers in India. UNFAO, describes the desert locust as the most destructive migratory pest in the world.
- Desert locusts (Schistocerca gregaria) ravaged crops in north-west India.
Locust invasion and Indian Ocean Dipole
- The Indian Ocean Dipole is a phenomenon in which the western and eastern parts of the ocean warm differentially.
- A ‘positive’ dipole is when the western part is hotter by a degree or more than the eastern.
- Year 2019 saw one of the strongest positive dipoles in the Indian neighbourhood which brought on a difference of more than two degrees.
- Positive dipole brings excessive rains to India and West Asia.
- Last year, Monsoon lasted nearly a month more than what is normal.
- This extended Monsoon rainfall continued in several parts of West Asia, Oman, Yemen and in the Horn of Africa — Ethiopia, Somalia, Kenya — so much so that that the dry sand became heavily moisture laden, facilitating the formation of several locust swarms.
- Favourable winds helped swarms to fly and breed in traditional grounds in Iran, Afghanistan, Pakistan and India.
- The normal locust season in India spans June-November and coincides with the kharif season.
Source: The Hindu and Deccan Herald
