Desert locusts may threaten crops along the border between Israel and Egypt as swarms have started forming following hatching in the Sinai Peninsula last month, the United Nations said.
Juvenile locusts known as hoppers continue to form groups in the northern border region, the UN's Food & Agriculture Organisation (FAO) wrote on its Locust Watch website on Wednesday. Immature adults are starting to take flight and may do so for another week, it said.
A swarm of locusts covering a square kilometre (0.4 square mile) is capable of consuming between 80 and 160 metric tons of crops a day, based on calculations using FAO data. Egypt is Africa's biggest grower of wheat and rice.
"Initially, the adults will move back and forth across the border and could threaten crops," the FAO wrote. "This is expected to be followed by a south-westerly migration to the summer breeding areas in central Sudan during June."
The groups and swarms of the plague insects started forming from infestations that were either undetected or untreated in both Israel and Egypt, according to the report. Infestations are also present in the southern Sinai, the UN agency reported. Survey and control operations in parts of the Sinai in Egypt are limited due to insecurity, it said.
An adult desert locust can eat food equalling its own weight of about 2 grams daily, and swarms can cover several hundred square kilometres, according to the FAO. A single square kilometre may contain 40 million to 80 million of the insects, it said. April 1961 was the last time locusts hatched and formed hopper groups in Israel, the UN agency reported this month.
In north-west Africa, limited spraying took place in spring breeding areas south of the Atlas Mountains in Morocco and Algeria, the FAO said.
Desert-locust distribution can extend over 60 countries during plague years, covering about 29 million square kilometres, according to the UN agency.