DAVAO CITY, 5 August — Pop singer Gary Valenciano has been dragged into a tax controversy in this southern city for his concert yesterday.  Valenciano, known in the music industry as Mr. Pure Energy, said the stiff amusement tax being imposed by the city government on his concert could have its adverse effect on the prospect of making Davao a concert capital of Mindanao.  In a press conference at Max’s Restaurant, he said the 30 percent amusement tax is too much for the organizers of any concerts held here in the city.  Angeli Pangilinan-Valenciano, wife and manager of Gary, said the ideal tax imposed for amusement-related events should be between 3-5 percent only.  She added that most of the local government units around the country have seen the deleterious effects of high amusement taxes and have instituted reforms to remedy the problem.  It was learned that amusement taxes among city governments now average from 10-15 percent.