Buzzing low over a field of hopping desert locusts, a Hercules C-130 transport plane released a fine plume of pesticide. But for Senegalese farmer Abdou Ngom, watching from his village of Cherif Lo, the American plane had arrived too late. ``They devoured all I had - three fields of cassava and a field of peanuts,'' he said, brushing at a black and yellow locust clinging to his shirt.
Last year, Mr. Ngom's 2 acres of land brought him $1,000, with which he supported his extended family of 24 people.
``This year I must rely on God,'' he said, ``for I have nothing else left.''
Just as it was recovering from two decades of drought, the arid Sahel zone of west Africa has been hit with the worst plague of desert locusts in 30 years. The swarms are thickest in Senegal, where the government estimates that locusts have infested almost 5 million acres of land and eaten 10 percent of this year's harvest. And although more than 2 million acres have been treated with pesticides, the insects reproduce so quickly that treated land often becomes reinfested.
``This is a very, very grave situation for the economy of Senegal,'' said Eloi Dieme, assistant director of Senegal's Crop Protection Service.
Solitary desert locusts live and breed throughout west Africa each year. But only under the right conditions of wind, temperature, and humidity will they aggregate into the ravenous swarms that have infested at least 12 African countries this year.
If the immature locusts currently in northwestern Senegal are allowed to mature into flying adults, they will form the biggest locust swarm in recorded history, according to entomologist Flip Philips, who works here with the United States Agency for International Development (USAID). If that swarm heads north, to the fertile Senegal River valley, or south, to the lush Casamance region, it could do at least $75 million worth of damage.
In response to the threat, USAID last week flew in the Hercules C-130 and two DC-7s for spraying, along with 43,000 gallons of insecticide. It is targeting 1 million acres in northwestern Senegal that must be sprayed in the next few weeks.
Immature locusts, known as hoppers, have no wings and march in dense formations. It is easiest to kill locusts in this form, for once they shed their shells and emerge as winged adults, they fly in swarms that are difficult to control.
The traditional method for killing a band of hoppers is to dig a trench, let the hoppers march into it, and then bury them. To encourage such safe, low-technology methods near villager's own fields, the Senegalese Crop Protection Service has distributed almost 3,000 shovels.
But with millions of locusts marching across remote areas, the use of pesticides has become a necessity.
Most of the control efforts involve two chemicals of relatively low toxicity which degrade quickly and therefore must be sprayed directly on the insects or the food they eat.
Private aid organizations in Dakar, the capital, and the Crop Protection Service have been setting up village anti-locust committees. Some villagers have been walking up to nine miles every day to dust the outlying areas.
At the village of Cherif Lo, about 45 miles east of Dakar, dozens of farmers, women and children were out dusting and spraying recently, advancing in a line across the fields.
Some, like Abdou Ngom, had already lost their own crops. Others were hoping to save what was left of their cassava and peanuts.
``We aren't discouraged by the huge number of locusts,'' said Assane Lo, president of the village anti-locust committee, ``because each one we kill is one that won't be back next year.''
In addition to hand sprayers, the protection service has 48 trucks equipped for spraying. A half-dozen light aircraft sent by various countries are also dusting, along with the three large planes sent by the US.
Locust experts with the United Nations Food and Agriculture Organization were hoping this week that the huge swarm in the northwest of Senegal would be blown west rather than to fertile areas in the North or South.
``If the winds keep up for the next week, these locusts will go out to sea,'' says geographer Elizabeth McVeigh.
But they will leave behind plenty of immature locusts, and experts fear next year's infestation may be worse. Some say the locust population here could continue to surge for a decade.