From a story in today's Los Angeles Times about narco wars in Mexico:
>Drug-trafficking groups have been drawn to the area for its fertile
>soil and convenient geography. The same qualities once made the area
>the center of an agricultural boom in the 1970s, when thousands of
>acres of cotton provided work. Water is plentiful, and the port at
>Lazaro Cardenas is only 90 minutes away.
>
>The boom crops are now opium poppies, which are processed into
>heroin, and marijuana. Cocaine shipped by sea from Colombia passes
>through by the ton, U.S. drug experts say. Chemicals from China are
>cooked into methamphetamine at clandestine labs.
>
>Rugged hillsides and protection money have made drug enforcement
>impossible. Traffickers take advantage of long-standing family
>relationships, as well as ambitious residents with few other means
>of getting ahead.
The "drug-trafficking groups have been drawn to the area" line suggests they were recently drawn. That leaves out the kick-start the U.S. gave to drug production in the area in WW II:
>Many trace Sinoloa's first narcotics crop--opium--to the numerous
>Chinese settlers who arrived in the last half of the 19th century.
>"It was a good agricultural place for it. And generation after
>generation the people just did it, they perfected it," explains
>Edward Heath, former Country Attache for the DEA in Mexico. But
>large scale production of opium didn't start until the 1940's and
>World War II. Japan gained control of the Asian opium supply and the
>U.S. military needed morphine for its soldiers. So the U.S. turned
>to Mexico for help. "We were concerned that our supply of opium or
>morphine would be cut off because the world was at war. So we needed
>a supply close by. But,that was one of those black box things. Who
>knows when it happened, who did it, and why." says Edward Heath.
>During this period of a government-tolerated opium trade, many
>Sinoloans made their fortune. "Everybody was growing it, it was
>institutional. Some government officials bought the harvest from the
>farmers to export themselves. There were even soldiers up in the
>hills caring for the plants," explains Dr. Ley Dominguez, a
>77-year-old life long resident of Mocorito, one of Sinaloa's most
>notorious opium regions. After Japan's defeat, however, the U.S. no
>longer needed Sinaloa's inferior strain of opium. But many farmers
>continued to produce opium and heroin; operations became more
>clandestine, and a smuggling network was set up.
http://www.pbs.org/wgbh/pages/frontline/shows/drugs/business/place.html