California prides itself on feeding America.

It also has the dubious distinction of being America’s biggest dope supplier.

Approximately 75 percent of the marijuana sold in the U.S. is grown in California — not Mexico, according to Sgt. Mike Horne of the Ventura County (Calif.) Sheriff's Department narcotics bureau. Horne heads a six-man commando-like unit that uses helicopters and rugged all-terrain vehicles to search and destroy marijuana growing operations in the national forest of his county.

This is not the typical article you find in an agricultural publication. However, Horne made his comments in a very typical agricultural setting, the recent California Weed Science Society annual meeting in Santa Barbara, Calif. The weed Horne was talking about has likely never been the topic of the society’s annual meeting in its 64-year history, where the presentations center around controlling unwanted weeds like horseweed, morningglory and Johnsongrass — not pot.

Horne was invited to speak on marijuana cultivation as the tentacles of these illegal operations pervade the rural, agricultural areas of the state. Marijuana cultivation has grown to the point where it is making it dangerous for government employees like University of California Cooperative Extension farm advisors to do their jobs.

Michelle Le Strange, UCCE farm advisor in Tulare County and immediate past president of CWSS, said she has been warned by county officials and law enforcement officers that she should be alert in driving a county vehicle in rural areas because marijuana plantation tenders might think she is a law enforcement officer, and she could be in danger.

Horne said Le Strange and any government officials driving vehicles with government plates should be concerned because these marijuana plantations are operated by Mexican drug cartels, the same lawless gangs who are responsible for thousands of murders each year in Mexico. These cartels actually scour the U.S. Forrest Service lands in search of ideal growing sites, often adjacent to running streams. The cartels stock these plantations with people, drip irrigation tubing and chemicals to farm the illegal weed.

Horne showed a video and photos of what his men have uncovered in the national forests. As expected, there were neatly planted marijuana rows with drip irrigation tubing, the same as used by farmers. More chilling to the CWSS audience were the photos of not only automatic weapons confiscated in a raid, but pictures of chemicals and fertilizers used in these growing operations. The logos of many very prominent agchem and fertilizer companies were clearly visible. There were also photos of agchem products manufactured in Mexico, brought in by the cartels. Horne said many of those chemicals are not legal in the U.S.

Le Strange pointed out that chemicals and fertilizers used in these growing operations could well find their way in to streams and lakes. The unsuspecting public is likely to put the blame on agriculture for any contamination from these illegal chemicals or misuse of U.S. registered products.