Activist actor Martin Sheen was in Philadelphia Friday to lead a rally outside a supermarket in support of Cesar Chavez's grape boycott. Sheen was joined by Michael Fisher, executive director of the Sierra Club, at the Carrefour store to urge customers not to buy grapes because growers are using too much pesticide on them. "Grapes are the one crop that receives the heaviest dosage of pesticides, particularly the most lethal pesticides," Sheen said. "It's like Agent Orange dumped on the foods."