WASHINGTON -- Peruvian avocado farmers can once again peddle their black-pebbled fruit in the United States despite lingering concerns among California growers, under a long-delayed rule made final Monday by the Agriculture Department.

The additional imports of Hass avocados could mean lower prices and bigger selections for U.S. consumers. The Agriculture Department's decision will also please Peru, which has been trying to crack the U.S. market for many years.

"(Our avocados) will enter one of the largest markets in the world," Peru Agriculture Minister Adolfo de Cordova enthused in a prepared statement. "This will expand our market, benefiting thousands of producers."

Peruvian growers estimate they might ship 19,000 metric tons of Hass avocados to the United States annually, amounting to about 5 percent of U.S. fresh avocado consumption. Agriculture Department economists predict consumers will benefit as market prices could fall somewhere between 1 percent and 6 percent.

"It will provide Safeway Stores and our customers with a new source for Hass avocados during the spring and summer months, a period when consumption of avocados is at its highest while supplies are at their lowest," Mariano Cruz, Safeway's national commodity specialist, advised the Agriculture Department earlier this year.

Jose Luis Obregon, managing director for the Irvine-based Hass Avocado Board, added in an interview Monday that "there's still a lot of room for the market to grow, especially on the East Coast."

But even as Peruvian officials were convening a celebratory news conference in Lima on Monday, U.S. growers were still chewing over the Agriculture Department's decision. Some have feared domestic groves might be in danger, despite extensive anti-pest protections imposed as part of the agreement to admit Peruvian avocados.

"We have concerns about the unknowns," California Avocado Commission president Tom Bellamore said in an interview Monday, adding that "some kind of track record will bolster everyone's confidence."

At the same time, Bellamore added that "we welcome" protective measures imposed by the Agriculture Department and the "consideration" officials have given to the economic threat posed by the Mediterranean fruit fly and the avocado seed moth.

California accounts for 86 percent of U.S. avocado production, including nearly all of the country's Hass avocado production. Most of the 4,801 California avocado farms are clustered in San Diego, Ventura, Riverside and Santa Barbara counties, although there is some commercial production still taking place in the southern San Joaquin Valley.

Citing similar concerns about the introduction of foreign pests, California growers had previously raised concerns about allowing imports of Hass avocados from Mexico. For both Mexico and Peru, U.S. officials imposed systematic inspection, packaging and sanitation requirements as a condition of allowing the imports.

Agriculture Department officials on Monday noted that over the past nine years, more than 28 million Hass avocados from Mexico have been inspected. Dangerous pests were found only twice.

The rules that take effect Feb. 10 are somewhat stricter than those proposed a year ago.