Aug 20 (Reuters) - Wall Street’s main indexes opened higher on Friday, lifted by a rise in technology stocks, although concerns over a slowing economic recovery and the possible tapering of monetary stimulus put the Dow and the S&P 500 on course for their worst week since mid-June. The Dow Jones Industrial Average rose 23.84 points, or 0.07%, at the open to 34,917.96. The S&P 500 opened higher by 4.76 points, or 0.11%, at 4,410.56, while the Nasdaq Composite gained 29.74 points, or 0.20%, to 14,571.53 at the opening bell. (Reporting by Devik Jain in Bengaluru; Editing by Maju Samuel) Our Standards: The Thomson Reuters Trust Principles.