Mayor Rudolph Giuliani said residents should not be alarmed by the discovery of infected mosquitoes or the ground spraying of pesticides that can cause breathing problems for the elderly and people with respiratory problems.
"The public should not have a great deal of apprehension," Giuliani said at news conference Monday. "Go about your lives normally, but for one night, stay out of the park."
The spraying canceled a free performance by the New York Philharmonic, which had been expected to draw 30,000 people.
Mosquitoes carrying the West Nile virus were also found on Staten Island. The discovery of infected mosquitoes marks the first time that the deadly virus has been found in the city this year. The virus was found earlier this summer in birds and mosquitoes in the suburbs around the city.
Previously scheduled spraying will also take place in Staten Island on Monday night and parts of Queens and Brooklyn on Tuesday.
The West Nile virus killed seven people and infected 62 others in the New York metropolitan area last year.