Thousands of trees along the Canal du Midi in France are being felled because they have been infected.
Another 2,200 plane trees are due to be chopped down and burned on the spot. This will bring the total to more than 15,000 since the first trees were felled in 2006.
The French waterways authority fears that all 42,000 plane trees may have to be destroyed. It has pledged to replace them with various types of trees, such as pine, poplar and oak.
A public appeal for funds raised more than €500,000 for the effort.
The killer fungus has been identified as Ceratocystis platani, which is believed to have been first entered France in contaminated ammunition boxes used by US troops during WWII.
Ropes moored to the trees by local boat traffic is believed to have helped spread the fungus.
The Canal du Midi runs for 250km, linking the Atlantic and Mediterranean. It was planted up with plane trees to give shade and reduce evaporation and erosion.
King Louis XIV, the sun king, gave the order for the canal to be created. Work started in January 1667. The plane trees were planted in the 1830s.
Unesco recognised the canal as one of “the most remarkable feats of civil engineering” as well as a natural work of art.
