UPDATE 1-Lockheed cites F-35 software issue, no delay in Marine target combat use

WASHINGTON, Feb 18 (Reuters) - Lockheed Martin Corp may need to update the F-35 fighter jet's software after issues arose during testing, but that should not delay the U.S. Marine Corp's plan to declare the jet ready for initial combat use in July, the head of the company's aeronautics division said Wednesday.