ABIDJAN, Oct 3 (Reuters) - Heavy rain last week in some of Ivory Coast's cocoa-growing regions has caused plant disease to spread, farmers said on Monday, raising concern for the early stage of the October-to-March main crop.

Ivory Coast, the world's top cocoa producer, is in its rainy season that runs from April to mid-November.

In the southern and coastal regions, farmers said they feared that too much precipitation this month would prevent them drying out beans properly and reduce the harvest.

In the eastern region of Abengourou, known for the good quality of its beans, farmers said that black pod disease was spreading on plantations due to excess moisture. But it is too early to be pessimistic about the harvest, they added.

"Lots of pods are blackening because of black pod disease," said Emmanuel Kassi, who farms in the outskirts of Abengourou, where 46.2 millimetres (mm) of rain fell last week, 22.5 mm above the five-year average.

Cases of the fungal disease were also reported in the western regions of Soubre and Man and in the southern regions of Divo and Agboville, where rains were well above the average, but farmers there said growing conditions there remained adequate.

Harvesting will rise gradually this month and reach its peak in November and December, farmers said.

In the centre-western region of Daloa, farmers said that many workers were in the bush harvesting but sales were slow.

"There are large stocks but buying for the moment is timid," said Justin N’Dri, who farms near Daloa, where 30.1 mm fell last week, 0.1 mm above the average.

Similar comments were reported in the central regions of Bongouanou and Yamoussoukro, where rains were below the average.

The government on Friday raised its guaranteed price paid to producers to 900 CFA per kg, compared with 825 CFA francs previously.

Weekly average temperatures ranged from 23.8 to 26.2 degrees Celsius in the West African country. (Reporting by Loucoumane Coulibaly; Editing by Nellie Peyton and Mark Heinrich)