A mysterious disease is affecting growth of cloves, Zanzibar's major export crop causing panic among farmers in Unguja and Pemba.

This has prompted the Zanzibar Minister for Trade and Industries Development, Mr Omar Said Shaaban, to direct researchers to investigate the disease-causing wilting of cloves leaves.

More than 500,000 clove trees have been affected in the Unguja North region.

"We need to speed-up the investigation. I urge farmers to be calm. I hope we will soon identify the problem and solve it," said the minister after visiting some of the affected clove farms in North Unguja.

Clove farmers including Mr Ali Juma explained that they started witnessing problems on the clove growth in January this year, but did not have idea about the disease which is already frustrating them.

"We need help from the government to intervene using its experts," he appealed.

Agriculture stands as an important sector in the Zanzibar economy, and the sector supports over 70 per cent of the island's population for their livelihood followed by trade and tourism.

Cloves have been a major foreign exchange earner in Zanzibar for the last 150 years and they continue to be an agricultural mainstay of the island.

However, due to fluctuations in production and price in the country and world market, Zanzibar government has been investing heavily by offering attractive price to farmers of 15,000/- per kilogram, free distribution of clove seedlings, establishing a clove development Fund, and fight against illegal transport to neighboring countries.

The government's initiative to revamp and increase clove production have been bearing fruits with Zanzibar's earnings increase. The monthly economic review of the Bank of Tanzania (BoT) for December 2021 shows that the value of clove exports was 50.7 million US dollars (about 120bn/-) compared to 18.2 million US dollars (43bn/-) garnered in 2020.