Forestry officials in southern Italy have cut down the first of thousands of olive trees infected with deadly bacteria in a controversial bid to prevent its spread.

The xylella fastidiosa bacteria has ravaged olive trees in the Puglia region and contributed to a 35 percent drop in the region's olive oil production last year. Its spread has so alarmed the EU that France announced a boycott of Puglian vegetables.

Puglian growers have opposed the government's slash-and-burn plan, saying it won't contain the bacteria's spread.

Several dozen protesters tried unsuccessfully Monday to block the first seven trees from being felled in Oria, near Brindisi, even climbing the branches and shouting "assassins." Eventually, the first seven trees were cut down and are to be burned Tuesday, with more to follow.