(Bloomberg) -- Spanish grape prices increased 15 percent to 20 percent as wine production in the country is set to decline this year, U.S. wine broker Ciatti Co. said. Wine output in Spain will probably slide 7.5 percent to an estimated 38 million hectoliters (1 billion gallons) to 39 million hectoliters, San Rafael, California-based Ciatti said in a report on its website dated Oct. 14. Adverse spring weather that caused disease including mildew and a vine-uprooting plan are the main reasons for the expected drop, according to Ciatti, which says it’s the world’s largest broker of bulk wine. Uprooting removed 70,000 hectares (172,970 acres) of vineyards in the La Mancha region over the past three years and 90,000 hectares across the country, equating to a production drop of more than 10.5 million hectoliters, the broker said