Ghana’s main-crop cocoa harvest fell 6% to a three-year low after a disease destroyed crops, according to people with direct knowledge of the matter.

The world’s second-largest cocoa producer harvested 776,418 tons during the main crop, the larger of two annual harvests that ended May 30, said the people, who asked not to be named because they are not authorized to speak publicly about the matter. The nation will probably miss its 50,000-ton estimate for the smaller harvest that ends in September, the people said.

Calls to the mobile phone of Fiifi Boafo, a spokesman for the regulator, didn’t connect.

Ghana has experienced an unusually severe outbreak of swollen-shoot virus, which can deform cocoa pods and reduce yields. The country’s cocoa regulator originally forecast an annual harvest of 900,000 tons, but cut its estimate to 850,000 tons and then 800,000 tons, people familiar with the matter said previously, after the disease affected crops in its biggest growing region.

“There is very little hope for the mid-crop, the disease has been devastating,” said Joseph Essuman Acquah, 70, who cultivates 30 acres (12 hectares) of cocoa in Yakasi, on Ghana’s southwestern border with Ivory Coast.

Ghana’s harvest contrasts with that of top producer Ivory Coast, which is poised for a record crop. The International Cocoa Organization in May cut its outlook for a global surplus to 36,000 tons in the season through September, from a prior estimate of 39,000 tons.