BRUSSELS, April 22 (Reuters) - The fight against cocoa swollen shoot disease in Ghana in slow going, with the world's second largest bean producer in need of an estimated $2 billion to treat all its infected cocoa growing land, the head of cocoa regulator Cocobod said on Monday.

Joseph Aidoo told Reuters on the sidelines of the World Cocoa Conference in Brussels that Ghana had over the past four years treated just 100,000 hectares worth of infected cocoa plantations, leaving another 500,000 still to be treated.

Global prices for the chocolate-making ingredient have nearly tripled in the past six months alone thanks primarily to soaring rates of swollen shoot disease in Ghana and neighbouring Ivory Coast, who together produce more than 60% of the world's cocoa.

Aidoo said although it is still early days, he expects the country’s cocoa crop will recover to 600,000 tons next season from at most 500,000 tons this season. The West African nation traditionally produces more than 800,000 tons of cocoa a year.

It has in recent years however, been hit not just with a worsening swollen shoot outbreak, but has also struggled with aging trees, illegal gold mining, climate change and sector mismanagement.

Ghana managed to raise around $350 million from the African Development Bank in 2020 to treat swollen shoot, Aidoo said, and last year clinched a loan of about $100 million from the World Bank to tackle the outbreak.

The funds are however nowhere near enough, he noted, pointing to the amount of cocoa growing land still infected – an estimated 17-20% of the country's total cocoa area – and to the fact that just 100,000 hectares have been treated over the course of four years.

The still high rates of disease limit how much Ghana's crop can recover next season, though the fact that the EL Nino weather phenomenon has passed and at least some land has been treated leave some room for hope, according to Aidoo.

The global cocoa market is widely expected to record a fourth successive deficit next season, and industry experts at the conference told Reuters they are concerned that Ivory Coast is doing far less than Ghana to treat the disease.

(Reporting by Maytaal Angel, Editing by Nigel Hunt, Louise Heavens and David Evans)