WASHINGTON -- Cuba and the United States are engaged in a diplomatic dispute over a flight by a U.S. plane that Havana alleges engaged in ``biological aggression'' by releasing plant-destroying insects over the island.

After a complaint to U.S. diplomats, Cuba took its case to U.N. Secretary General Kofi Annan, charging that the pest ``strikes and severely damages practically every crop and is also resistant to a considerable variety of pesticides.''

On Tuesday, State Department spokesman John Dinger called the Cuban accusations outrageous and accused Cuba of ``deliberate disinformation.''

At issue is a flight over Cuba last Oct. 21 by a State Department aircraft normally used in narcotics crop eradication. Cuba said the pilot of a Cubana Airlines plane flying nearby saw the American plane emit a ``white or grayish mist.''

An investigation determined that the substance released was a biological agent known as the thrips palmi insect, Cuba said. It added that the first sign of the plague appeared in potato fields in Matanzas province two months later.

Considering the insect's reproductive cycles, Cuba said the beginning of the infection can be traced to the precise time when the U.S. aircraft flew over the island.

``There is reliable evidence that Cuba has once again been the target of biological aggression,'' the Cuban note to the U.N. secretary general said. In the early 1980s, Cuba accused the United States of triggering an outbreak of dengue fever on the island.

Dinger said the pilot of the State Department plane observed the Cubana Airlines plane flying below him and alerted the aircraft to his presence by triggering his smoke generator, a ``prudent and safe'' way to inform the Cuban pilot of his presence.

The plane was en route from Florida to Colombia via Grand Cayman island, Dinger said. The aircraft had Cuban permission to fly over the island.

U.S. officials said credibility of the Cuban claim is undermined by the fact that the thrips palmi insect struck Haiti, Jamaica and other Caribbean islands before infesting Cuba.

News accounts from Cuba say the thrips palmi insect, which originated in Asia, has infested 15 crops in three of Cuba's 14 mainland provinces and the Isle of Youth, off the country's south coast.

Copyright © 1997 The Miami Herald