James Danny (48), from Solang village, Lou Island, was found guilty for being in possession of dangerous drugs and cultivating dangerous drugs.
Police conducted the raid on November 16 and uprooted marijuana plants in a garden. They also confiscated some drugs in his house.
He now remains in custody at Lorengau, awaiting his sentence.
Manus Provincial Police Commander, Chief Inspector David Yapu, said Danny was a threat to the community due to his involvement in drug activities in the community.
He thanked leaders from Solang village, Lou Island, for reporting the incident to police and is appealing to other community leaders to report such incidents involving drug activities.
He is warning youths to stay away from drugs and homebrew and focus on activities that will sustain their future to become good citizens in their community.
Yapu said drugs are now grown in Manus Island and sold to youths in town where in previous cases, they were transported by boat from Madang, Wewak or Kavieng to Manus.