Chinese gangs have set up thousands of illicit weed farms across the US as they begin to challenge Mexican cartels for supremacy as America's cannabis kingpins. Authorities in Oklahoma, Oregon, California, New Mexico and Maine have all been battling a surge in Chinese weed farms, with some thought to be linked to criminal gangs known as 'triads'. The spread is seemingly uncontainable, with police in Penobscot County, Maine, last week arresting three Chinese nationals at a weed farm and seizing 40 pounds of the drug alongside $4,700 in cash. It is thought to be one of around 270 illegal weed...