BROWNSVILLE, Texas (AP) _ The handwritten sign nailed to a hackberry tree serves as a sardonic welcome to the Monsees Ranch: ``Marijuana Blvd. Since 1940.''

Julia Monsees posted it shortly after she and her husband bought the 30-acre property along the Rio Grande in 1940, when a neighbor pointed out that what Mrs. Monsees thought was an orange tree sapling actually was marijuana.

The Monsees homestead was becoming a highway for illegal immigrants and drug traffickers heading north from Mexico, and the marijuana had apparently sprouted from seeds that had fallen to the ground as the smugglers passed through.

In the years since, Mrs. Monsees has been threatened with a knife and robbed. She has found drugs stashed around the property and seen female immigrants who had been raped. She's even found her own dog, skinned and hanging from a tree limb.

In the war on drugs, the Monsees Ranch has become a battlefield.

``It's been mighty, mighty rough out here,'' said Mrs. Monsees, 84, who sleeps with a shotgun by her bed. ``At first I wanted to get rid of the place. Then I started fighting it.''

Other ranches along the Texas-Mexico border had told similar tales of drug lords terrorizing them.

One Texas rancher, cloaked in a black hood and raincoat, told a U.S. Senate committee this week that ranchers intimidated by rising violence were selling land to American representatives for Mexican drug traffickers.

Agencies charged with battling drug traffickers disagree on just how widespread the problem is on border ranches.

Leonard Lindheim, agent in charge of the Customs Service in San Antonio, said he believes ranchers are mistaking an increase in illegal immigration for heightened drug traffic.

``The type of complaints we're hearing are their fences are being cut, their cattle are being shot and butchered for food, their buildings are being broken into,'' he said. ``This is not drug trafficking; these are illegal immigrants. If I had one word to categorize the problem, it would be trespassing.''

Lindheim said drug traffickers have used border ranches to transport their goods since the '70s, but he does not believe activity has increased.

Jim Collier, the agent in charge of the Drug Enforcement Administration's San Antonio division, disagrees. ``It is prevalent and has increased in the last eight months, probably because of the increase in the availability of drugs generally,'' he said.

Collier said several recent drug seizures, including an 8,000-pound marijuana seizure in the border town of Eagle Pass, can be traced to ranch crossings.

Smugglers cross through private land because border ranches are located far from immigration checkpoints. Also, the ranches usually also have established trails that lead to hard-surface roads, where vehicles can pick up drug shipments.

Such is the problem on the Monsees Ranch, which is some 10 miles from an immigration checkpoint but less than a mile from the banks of the Rio Grande.

For decades, the Monseeses, who once grew cotton and now run a plant nursery on their ranch, have watched illegal immigrants scamper through their palm trees and heard automatic gunfire from shootouts between drug smugglers and Mexican authorities.

Mrs. Monsees' son, Rusty, patrols the property nearly every day. A former policeman, he lives with his family next door to the main house, where the family matriarch resides.

Monsees said he has been in shootouts with smugglers and often holds trespassers at gunpoint while waiting for Border Patrol agents to arrive.

His wife learned to fire a shotgun years ago and packs a pistol while on the property. Their children, 7-year-old Julie and 9-year-old Laura, have been taught to ``go for the floor when there's bad guys out.''

The Border Patrol frequents the property, Monsees said, apprehending at least 50 immigrants per day. In addition, Monsees said he consistently finds up to 30 pounds a day of marijuana, cocaine or black tar heroin.

In the thick brush adjacent to the ranch, black plastic bags covered with duct tape _ the kind used to carry bundles of drugs _ have been discarded next to the road, a sign to Monsees that smugglers loaded a truck just feet from his property line.

Despite all that, the Monseeses said they don't plan to give up.

``It's a war, yeah, but it can be won,'' Monsees said. ``People have got to get out there and do something about it.''