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12 August - The United Nations Food and Agriculture Organization (FAO) today warned that Madagascar is at risk of a crop-eating locust plague, potentially jeopardizing the livelihoods of 460,000 rural families.

An unknown number of immature swarms of Malagasy Migratory Locust have moved out of the country's south-western corner, where they are usually contained, and have spread to the east and north.

FAO said today that a major air and ground control campaign lasting months is needed ahead of Madagascar's upcoming rainy season, which kicks off in mid-October, to stave off a potential plague.

The country is currently in its dry and cool season, which is unsuitable for locust breeding, but the wet and hot rainy season, which lasts until spring, favours rapid reproduction.

In suitable conditions, locusts can produce a new generation every two months and up to four annually.

FAO carried out a field assessment mission to Madagascar last week, in coordination with national authorities, which confirmed that the situation is serious and that aerial surveillance of the movement of the locusts must be initiated by early next month.

The agency said that $15 million is urgently needed to mount a campaign on some 500,000 hectares of land.

Locusts do not always stay in swarms. In south-western Madagascar they typically live on their own as individuals.

But if their population density passes the tipping point, their body chemistry changes and they undergo a behavioural, ecological and physiological transformation.

After these changes, individual locusts begin to concentrate and act as a synchronized group of hopper bands, or wingless locusts, or as adult swarms, moving out en masse to find new food sources. Changes in their bodies allow them to fly over greater distances, up to 100 kilometres a day, as well as making them able to digest a wider range of vegetation and crops.

An adult locust can consume its own weight – roughly two grams – in fresh food daily. A very small part of an average swarm eats the same amount of food in one day as about 2,500 people.