PORT-AU-PRINCE, Haiti — Hurricane Gustav dumped torrential rains across southern Haiti on yesterday, killing at least one man and threatening crops amid protests over high food prices. Oil prices rose on fears the storm could batter oil rigs in the Gulf of Mexico.

Trees toppled as the storm lingered for hours over Haiti’s poor, deforested southern peninsula, and water levels were rising in banana, bean, and vegetable fields. One man was killed in a landslide in the mountain town of Benet, the civil protection director, Marie Alta Jean-Baptiste, told Radio Metropole.

“If the rain continues, we’ll be flooded,” a U.N. food consultant, Jean Gardy, said from the southeastern town of Marigot.

Hundreds of people in coastal Les Cayes ignored government warnings to seek shelter, instead throwing rocks to protest the high cost of living in the Western Hemisphere’s poorest country. Witnesses said U.N. peacekeepers used tear gas to disperse the crowd.

Haiti is a tinderbox because of soaring food prices, which in April led to deadly protests and the ouster of the nation’s prime minister. It was difficult to ascertain the extent of the damage from the Category 1 hurricane to the nation’s crops yesterday because of Haiti’s poor infrastructure and faulty communications.

After Haiti, Gustav was projected to sideswipe Cuba’s southern coastline all week and grow into a perilous Category 3 hurricane with 120 mph winds before entering the central gulf on Sunday. Forecasters were reluctant to predict the storm’s path beyond the weekend, the third anniversary of Hurricane Katrina.

The American military base at Guantanamo Bay, Cuba, had been expecting a direct hit, but later forecasts suggested the fiercest winds and rain will pass offshore. A base spokesman, Bruce Lloyd, said they were preparing for emergencies in any case.

A powerful storm in the gulf could force shutdowns on the offshore rigs that account for a quarter of American crude production and much of its natural gas. Royal Dutch Shell PLC said it could begin evacuating workers as soon as today.

The price of light, sweet crude for October delivery ended testerday up $1.16 to settle at $116.27 a barrel on the New York Mercantile Exchange after the National Hurricane Center predicted Gustav could enter the gulf as a major hurricane this weekend.

If the storm continues on its path, it could drive up American gasoline prices by 10 cents a gallon ahead of Labor Day weekend, predicted the president of Tampa, Florida-based Liberty Trading Group and OptionSellers.com, James Cordier.

“Most indications are that Gustav will be an extremely dangerous hurricane in the northwestern Caribbean Sea in a few days,” the Miami-based hurricane center said.