The city of Matsumoto in Nagano Prefecture has been struggling to cope with serious damage to pine trees in its mountain forests caused by pine wilt, the disease seen with infestation by the pinewood nematode parasite that can kill affected trees within a few weeks.

Some local residents have called on the municipal government to continue a program of aerial chemical spraying using unmanned helicopters, but others have questioned its effectiveness and safety.

Yoshinao Gaun, who became the city’s mayor in March, said Tuesday that the municipal government has decided not to conduct the aerial spraying that had been scheduled for fiscal 2020.