TORONTO - Illegal marijuana cultivation has reached epidemic proportions in Ontario and justice officials in the United States have branded their northern neighbour a "source country," the province's top police official said Wednesday.

Marijuana is exported south and traded for crystal meth and crack cocaine which are then brought back into Canada, provincial police Commissioner Julian Fantino said Wednesday.

"The going terminology is 'brown south, white north,"' Fantino said, adding marijuana is also being exchanged for guns.

"It's a black eye on Canada when you have the United States... refer to us as a source country of marijuana."

Investigating and shutting down marijuana grow-ops make up 60 per cent of the workload of the force's drug enforcement unit, said OPP Insp. Brian Martin.

Cracking down on those operations should help drive down the import of crystal meth and crack cocaine, he said.

"You have to stop the problem at one end and hopefully that product's not coming back in."

Provincial police announced it seized and destroyed more than 118,000 marijuana plants from 220 grow operations, charging 56 people during its annual eight-week marijuana eradication program - up from 10,000 plants from last year.

Over the last five years the force has investigated nearly 2,800 grow-ops. They've also seized more than 2,700 weapons.

An increasing number of suppliers are moving from indoor to outdoor grow-ops, which can produce more plants, police said.

The OPP found one outdoor operation producing 40,000 plants.

There is also an "alarming increase" in the use of loaded weapons, animal traps, armed guards and even illegal immigrants by growers to ward off so-called "pot pirates" and police, they said.

Organized crime is a huge operation with tentacles that reach internationally and its involvement in grow-ops is increasing, said Fantino.

"Organized crime will use whoever and will do whatever (to) achieve their goals and objectives, which is to make these obscene profits illegally."

The "drug subculture" was responsible for what Fantino called an epidemic of very serious crimes, such as robberies, several years ago in Orillia, Ont.

"(Marijuana) is the precursor, if you will, to so much of the violence and other activities... that end up victimizing the most vulnerable communities," he said.

"You know full well what the consequences of what crack does to a neighbourhood, the vulnerability of some of these people in these neighbourhoods, the violence associated with it."

The fight against drugs just isn't about "smoking a little joint here and there."

"It's about the bigger picture... It's a public safety threat, it's an officer safety threat," he said.

Canada is too soft on drug-related criminals, Fantino added.

"Those (criminals) working cross-border, we'd love for them to get indicted into the United States because that's where they're really going to get the business."

While Fantino conceded police are fighting an uphill battle against the grow-ops, and that the battle will never be won, he added things would be much worse if police weren't combating drugs.