Harvard students should participate in a national boycott of California grapes and urge the dining halls to stop serving them, farm worker activisit Cesar Chavez said at a speech at Lowell House last night.

Chavez, the leader of the United Farm Workers (UFW), said the University should join such schools as the University of Massachusetts at Amherst and Mount Holyoke to ban the grapes, which are treated with pesticides harmful to farm laborers.

He added that students should picket Harvard's Dining Hall Services if it continues to purchase California grapes.

"It is at the marketplace where we make legislation," Chavez said. "It is at the marketplace where the union was born, it is there that the union will continue to be," Chavez told the audience of more than 100 students and members of the Harvard Union of Clerical and Technical Workers (HUCTW).

The work dealing with the enormous problems with the environment caused by these pesticides must continue. We believe that the only place that can be done is at the marketplace," Chavez said.

Chavez said a consumer boycott was the only effective way for the UFW to force grape growers to stop using what it considers carcinogenic pesticides. "The boycott works," Chavez said repeatedly.

"[The UFW were] the first ones to ban the use of pesticides...such as DDT...anywhere in the whole, wide world," the activist leader said.

Chavez said the purpose behind the boycott is not to eliminate the grape growers' market entirely but to cut back on grape sales by about 11 percent. Such a fall in sales would persuade grape growers to deal with the union but would not hurt the grape worker, Chavez said.

Lowell House Master William H. Bossert '59 said pesticides only increase grape yield by 7 to 10 percent, adding that "the underlying problem is the pesticide companies. They're the only losers in this [if the grape growers stop using pesticides]."

Sheila deB. Schimmel, assistant to the master at Lowell House, attributed the large contingent of HUCTW members to Chavez' request that "specific interest groups" be notified of the speech. She said the activist leader singled out "labor, animal rights [groups], union and the gay community."

Chavez prefaced his presentation by complimenting the meal that had been served to him earlier. "I was glad to see there were no grapes on the table," he said.