HAVANA (Reuters) - Cuban annual raw sugar production will fall below 200,000 metric tons in 2025 for the first time since the 19th century, potentially leaving rum makers short of a key ingredient, according to recent official reports and an industry source.

State-run monopoly AZCUBA planned to produce 265,000 metric tons of raw sugar this year. But as the milling season has neared its end, output was running about 100,000 tons short, a Reuters estimate found, based on official media reports and sources with knowledge of the situation.

Cuba produced 350,000 metric tons of sugar in 2023, its most recent data, compared with 1.3 million in 2019.

The Communist-run Caribbean Island nation, at one time a major sugar exporter, will have to import more than it produces this year to meet bare minimum demand, offering little solace to rum distilleries, which can only use local product.

The National Statistics and Information Agency reported production of sugar-based 96% ethanol alcohol -- used in distilling quality rum -- plunged 70% from 573,000 hectoliters in 2019 to 174,000 last year. Another grade of alcohol used in some other rums fell a similar amount.

The outlook is the latest sign of Cuba`s collapsing economy, ravaged by U.S. sanctions, inefficiencies and the COVID-19 pandemic. Sugar cane production and sugar milling have dropped due to shortages of key inputs and mismanagement.

An authentic Cuban rum must use alcohol produced from Cuban cane sugar, but plunging production has unsettled the industry, a foreign businessman told Reuters, requesting anonymity.

"Because rum must age, we have been using our stocks and the concern is, will we have new stocks looking forward?" he said.

Though sugar mills remain open, yields typically drop sharply in May as summer rains complicate processing.

Just one of 13 sugar-producing provinces, Sancti Spiritus, had completed its plan of a comparatively meager 19,000 tons by May. Villa Clara province, once a sugar powerhouse, reported hitting 38% of a 27,000 ton target, and Cienfuegos reached about two-thirds of a 38,000 ton plan.

In eastern Cuba, Las Tunas province reported output at 5,000 tons, 11% of its plan. The Communist Party newspaper in Las Tunas blamed industrial breakdowns, fuel shortages and a lack of lubricants -- a common refrain across the industry.

The Caribbean island nation was once the world's top sugar exporter, churning out 8 million metric tons of raw sugar in 1989. The collapse of its former benefactor, the Soviet Union, sparked a steady decline.