MENDOTA, Calif. — Westside Grocery, serving this self-described Cantaloupe Center of the World since the 1940s, removed its gasoline pumps around 1980, the result of increased regulation. Fresh steaks and pork chops went by the wayside in the 1990s: too few could afford them.


Fresh milk was the next casualty. No one ever seemed to hurt for money for beer, but Westside Grocery eventually stopped selling that, too. “Too many alcoholics stinking of urine and worse,” said Joseph Riofrio, who took over the business from his father, who had taken it over from his. “But the truth is that the electricity for the cooler was getting expensive.”


Now Westside Grocery is gone. Last month, Mr. Riofrio, a City Council member and former mayor of this Central Valley town, where a street is named after his grandfather, pulled the plug — done in by a 38.7 percent unemployment rate, the foreclosure and credit crises and hoped-for economic help that never came. “How can a community in the heart of the most abundant farmland on earth suffer this way?” Mr. Riofrio said, fighting back tears.


Another question: If Mr. Riofrio, 50, cannot make it here, can anyone?


The Detroit of California. The Appalachia of the West. This town of 11,100 has been called both, and it is not an exaggeration. About half of Mendota’s residents, according to city officials, live below the poverty line. Alcohol abuse is unbridled. A recent killing appeared to be tied to the violent street gang MS-13.


Mendota has garbage collection, but you would not know it from looking at some of the front yards along Juanita Street. A squalid trailer park greets people arriving from Fresno, about 35 miles to the east; to the south is a prison, built in a former cotton field. Shopping is mostly done at Dollar City or the 99 Cents Store, both competitors of the 98 Cents Store.


Although Mendota is in especially bad shape, the entire Central Valley has been hit hard by the recession and sluggish recovery. Unemployment for the region is about 15 percent. Stockton, on the valley’s northern end, filed for bankruptcy protection in June. A homeless camp continues to grow at a Fresno exit along Route 99. Bakersfield, to the south, has perked up lately, but it has something the rest of the valley does not: oil and natural gas fields and proximity to Los Angeles.


Unemployment has long been a reality in Mendota, which was first settled in the 1890s as a railroad stop. California’s agricultural towns rise and fall depending on what crop needs picking and how much water is available for irrigation. Social problems are nothing new, either. “The fields have always been a magnet for impoverished people trying to find a way out,” said Rick Wartzman, the executive director of the Drucker Institute at Claremont Graduate University and the author of several books examining the Central Valley.


Still, Mendota’s unemployment rate is high even by farming community standards, which typically see a seasonal average of about 20 percent. As the worst of the worst, Mendota has gotten its share of attention over the years; in 2009, when Gov. Arnold Schwarzenegger needed a backdrop to announce that he had petitioned President Obama to declare Fresno County a drought disaster area, he chose Mendota.


But nothing ever seems to get better here. That disaster request was declined. Thousands of acres of surrounding farmland — once used to grow corn, bell peppers, tomatoes and melons — have been forced out of production because of salt buildup, the result of flawed irrigation and drainage systems. Thousands of additional acres have been left fallow because of a lack of water. This part of the Central Valley relies almost exclusively on federal irrigation supplies that have been curtailed amid environmentalist pressure to restore fish habitat.


“There is more than one root problem, which is what makes Mendota so tricky to deal with,” Mr. Wartzman said. “Immigration, water politics, labor patterns, the tendency for California to forget its middle, farm legislation — it all contributes to the downward spiral.”