From a distance, it might have been mistaken for one of the thick sandstorms, known as haboubs, that suddenly fill the sky with a dusty-rose darkness, leaving fine grit between the teeth. But as it approached, the swarm of desert locusts moved overhead in tight, dark clouds. As they swooped down to eye level, the three-to-four-inch bugs looked silvery in the harsh morning sun.
Local men walking through the sandy streets in traditional snow-white galabias (long shirts) and swirled turbans pointed to the sky, pausing to watch the jagged path of flapping bugs.
Sudan's locust onslaught has taken a dramatic turn for the worse, according to a recent weekly update by the government. A total of 1.8 million acres are infested - most of them in the heart of the country's cultivated land. Control efforts have only reached about 750,000 acres, and agriculture experts say the swarming insects could destroy up to 80 percent of Sudan's crops this year.
The agriculture ministry's Plant Protection Department (PPD), which compiles the report, also says that swarms have begun to migrate, and a second generation of breeding has begun.
For months, international experts have been forecasting the worst plague of locusts to sweep northern Africa in more than a generation. During the last plague, in which the seasonal locusts recurred annually from l939 to l960, crop-devouring swarms surged from the Atlantic Ocean, across Africa, to the east as far as India. But even experts are surprised at the scale of the current infestation.
Unexpectedly good rains in Sudan and neighboring Chad created very favorable conditions for the swarms. Locusts deposit their eggs in moist, warm soil, and the offspring need good vegetation, both of which could be found in eastern Chad and western Sudan this year.
At the PPD office in northern Khartoum, the capital, a detailed map of Sudan covers one wall. Color-coded sequins are densely pinned from west to east, across the fertile central belt of the country.
The pins plot the locations of locusts at their various stages of development - from ``hoppers,'' which vibrate in clusters on the ground before sprouting wings, to immature and mature swarms, which can fly hundreds of miles in a single run, satisfying their voracious appetites on the verdant vegetation under wing. To successfully fight the swarms with pesticides, spraying must be done before the insects have passed the ``hopper'' stage.
Locust control experts have seen the locusts coming for months. But civil war in Chad, which has spilled over into Sudan's western Darfur Province, has made it impossible to monitor or spray some breeding areas in that sensitive region. Libyan forces in western Sudan, said to back Chadian rebels, have made such efforts even more difficult.
Likewise, the civil conflict to the east in Ethiopia prevents efforts to thwart the swarms as they leave Sudan headed in that direction.
Sudan's own civil conflict and a recent series of disasters - August's torrential rains followed by devastating floods - virtually paralyzed all systems for several weeks. Mechanical breakdowns, lack of spare parts, and customs bottlenecks which block imports including vital communications equipment have all hobbled efforts to spray for locusts.
``The number one problem is communications, not getting information fast enough from isolated provinces in the field, to regional sections, to headquarters here in Khartoum,'' said Keith Cressman, an entomologist from the United Nations Food and Agricultural Organization (FAO), who works with the PPD.
Locust control experts in Sudan say it is almost impossible for them to effectively track the moving swarms. While tracking by satellite is available, reports from such monitoring are outdated by the time they reach officials here.
The best the PPD can do is concentrate on protecting Sudan's few areas of intensive cultivation - monitoring them with about 20 light planes, and hundreds of nomad scouts who ride camels and donkeys over the parched plains.
Sudan is Africa's largest country, covering an area more than three times the size of Texas. It is also one of Africa's poorest states, lacking paved roads and reliable communications to most of the country.
Crucial to Sudan's economy is Ghezira, the fertile wedge of land between the White and Blue Niles. Cotton, wheat, sorghum, and ground nuts are produced in this irrigated area. Further east, around Gedaref, is another key wheat and sorghum belt.
Locust control and agricultural experts maintain that it is impossible to give precise figures on potential crop damage. Mr. Cressman said that the loss in agricultural output could range from as low as 10 percent ``all the way up to 100.''
But he added, ``I guess you can expect the worst, and say that Sudan's going to have a big problem with their food production this year as a result of the locusts.''
Where the swarms will go after crossing Sudan will depend largely on wind patterns and weather conditions.
The FAO expects the locusts to move east to Ethiopia, then down over Somalia and into Kenya, where lush, green farmlands dot the landscape. The FAO predicts that this will happen by January, but it could happen as early as this month.