The UN Food and Agriculture Organization (FAO) has warned that a dangerous infestation of locusts could emerge along the Red Sea in November and December following an outbreak of the insects in northern Sudan.

"Recent field reports indicate that locust numbers have increased in the summer breeding areas in Sudan, primarily north and east of Khartoum where ground surveys could be conducted," FAO said in a statement on 12 November.

Desert locusts are migratory grasshoppers that often travel in vast swarms. According to FAO, they live for about three to five months, and one adult consumes roughly its own weight in fresh food per day - about two grams. A small swarm eats as much food in one day as about 2,500 people.

The agency said unusually favourable breeding conditions had caused wingless hoppers (the second phase in a grasshopper’s life) to concentrate and form small bands, while adults (locusts) had formed several small swarms.

The Sudanese government mobilised aerial and ground control teams and had already treated more than 11,000 hectares, FAO said.

However, it said finding and treating all locust infestations in the remote desert areas of northern Sudan was difficult.

"Consequently, more swarms could form in the interior and move to the Red Sea coastal plains in Sudan during November," the agency added.

Although the risk of infestations spreading from Sudan to adjacent countries remained low, small locust populations had been reported along the Red Sea coastal plains in Yemen and northern Eritrea.

"If good rains fall along the coast this winter, locust numbers are likely to increase dramatically and significant infestations could develop by February that would require substantial control operations," FAO said. "Once conditions dry out along the coast, locust swarms could form and move towards the east to the Arabian Peninsula and towards the west to Darfur by early summer."

In August, Yemen was hit by the worst infestation of locusts for almost 15 years after heavy rains. The density of the locusts was high, posing a serious threat to agricultural land in both the north and south of the country.