18 December 2003, Rome -- After a summer season of good rains and recent favourable rainfall, Desert Locust populations continue to increase and may threaten winter crops in northwest Africa and along the Red Sea, FAO warns today.

Swarms started to form in Mauritania where breeding continues in many areas. During the first ten days of December, 12 swarms of immature locusts were seen east of Nouakchott, while three other swarms flew over the capital itself on 4-6 December, according to a new report by the FAO Locust Group.

More egg-laying and egg-hatching has occurred east of Nouakchott and in the north of the country near the mining town of Zouerate. Hopper bands are forming there as well as in other parts of northwestern Mauritania, the report also said.

In Western Sahara, mature groups of adults are present from the Mauritanian border to Bir Anzarane. In this area, as well as in northern Mauritania, low temperatures may delay locust maturation during the winter.

In Mauritania, so far nearly 20,000 ha were treated with pesticides during ground control operations while some 2,400 ha were treated in Western Sahara, according to recent information.

Although locust numbers are declining in Mali and Niger, group of hoppers and young adults remain in the traditional breeding areas of Tamesna and Adrar des Iforas (Mali) and in the southeastern Air Mountains (Niger).

"Bands are forming in Mali where one swarm has been reported so far," the report said. More swarms may develop and move northwards, threatening northwest African countries.

The Middle East at risk

Another dangerous situation is reported in Sudan where a mature swarm arrived on the Red Sea coast from nearby outbreak areas near the Atbara River in the interior of northeastern Sudan.

More adults groups and a few swarms are expected to appear on the Red Sea coastal plains of Sudan and lay eggs that will hatch in the coming weeks.

Adult groups and swarms may also continue across the Red Sea to Saudi Arabia where locusts were seen laying eggs on the coastal plains between Jeddah and Yenbo.

Still in Saudi Arabia, some groups moved towards the hinterland in areas close to the towns of Medina and Taif where they laid eggs. "This is very unusual at this time of the year," the FAO report said. Hatching has already commenced in some areas and hoppers are forming bands.

Control operations treated some 3,600 ha during the first week of December in Saudi Arabia and operations continue in Sudan.

FAO experts fear an extension of the locust threat in the Middle East if good rains fall along the Red Sea coasts during the winter.

Desert Locust plagues

A Desert Locust is a grasshopper that modifies its behaviour and appearance in response to environmental conditions.

Desert Locust is normally found in the solitary phase at very low densities in the desert in about 20 countries between Mauritania and India.

When rainfall creates favourable breeding conditions, the locusts can multiply rapidly, concentrate and gregarize. This means that they act collectively, forming swarms of adults and marching bands of hoppers (wingless immatures).

Swarms are highly mobile, flying many hundreds or thousands of kilometres between summer, winter and spring breeding areas.

Plagues develop when the locusts find ideal conditions in a sequence of seasonal breeding areas. This leads to rapid multiplication and increasingly large swarms that also invade countries outside the traditional breeding areas.

Crop damage by swarms can be devastating. The years between plagues are referred to as a recession period.

FAO's Locust Group receives information and data from national locust units carrying out field surveys and control.

It provides early warning to affected countries and to the donor community by analyzing this information with meteorological, remote sensing and historical data and issuing forecasts, alerts and special warnings.

During emergencies, the Group coordinates control operations and external assistance.

More information is available on the Internet at : http://www.fao.org/news/global/locusts/locuhome.htm.

Pierre Antonios
Media Relations Officer, FAO
or media.office@fao.org
(+39) 06 570 53473
(+39) 06 570 53625