KINSHASA, Feb 22 (Reuters) - Crop-destroying caterpillars known as armyworms have ravaged 63,000 hectares of maize in southeastern Democratic Republic of Congo since December, causing local maize prices to triple, a U.N. spokeswoman said on Wednesday.

Suspected outbreaks have already erupted in Zambia, Zimbabwe, Malawi, South Africa, Namibia and Mozambique, and the outbreak in Congo is the first evidence it has spread into central Africa.

Scientists say the armyworm, which is native to North and South America, could reach tropical Asia and the Mediterranean in the next few years.

The 63,000 hectares in southeastern Congo represent 80 percent of maize production in four territories along the Zambian border, U.N. spokeswoman Florence Marchal told reporters in the Congolese capital of Kinshasa.

The outbreak has caused the price of a 25 kilogram sack of maize to rise from $10 to $30, she added, and comes as Congo's other main staple crops, bananas and manioc, are ravaged by other maladies.

Armyworm moths lay eggs in maize plants and the caterpillars have also been known to march en masse across the landscape. Countries with confirmed outbreaks can also face import bans on agricultural products.

(Reporting by Aaron Ross; Editing by Mark Potter) ((Aaron.Ross@thomsonreuters.com; +243 81 51 00 107;))