A Missisauga man has pled guilty in connection with one of the largest marijuana grow-op busts in Canadian history in the Upper Ottawa Valley.

Last September, Ontario Provincial Police seized 40,000 marijuana plants growing between stalks of corn on a former berry farm on B-Line Road in Laurentian Valley Township.

The bust uncovered more than $40 million worth of marijuana plants. An irrigation system apparently operated from a pond and above-ground swimming pool, according to police.

The OPP called it the largest grow operation seen since some 30,000 plants were seized from a Barrier brewery plant operation in 2003.

Viet Ha, 54, pled guilty on Tuesday to a charge of trafficking in Pembroke court.

With files from The Canadian Press