July 23 (Bloomberg) -- New York Times Co. plans to raise the newsstand price of its flagship newspaper by 25 cents to $1.50 starting Aug. 18 as a drop in advertising sales deepens.

The new weekday price follows a separate 25-cent increase a year ago and a rise in weekly home-delivery charges this month. Chief Executive Officer Janet Robinson made the announcement on a conference call today as she reported a 16 percent drop in June ad revenue. Second-quarter profit declined 5.5 percent.

``We see continued challenges for advertising in a faltering economy,'' Robinson said. ``We expect that this will continue for some time to come.''

While higher newspaper prices helped boost New York Times's circulation revenue in the second quarter, they failed to counter the industrywide drop in ad sales. Last week, News Corp.'s Wall Street Journal also said it will boost its newsstand price, by 50 cents to $2.

To contact the reporter on this story: Jennifer Sondag in New York at jsondag@bloomberg.net.

Last Updated: July 23, 2008 12:13 EDT