The Dow Jones industrial average fell 51.24 points by the close of markets Monday, pulling off a late rally after reaching a six-week low in the middle of the day. Analysts blamed the poor performance on worries from the Japanese quake: General Electric, as the supplier of the No. 1 reactor at the Fukushima Daiichi nuclear-power plant, fared the worst Monday, dropping 2.2 percent to end the day at $19.92. Walt Disney, whose Tokyo Disneyland and Disney Sea theme parks were both closed due to the earthquake, lost 1.6 percent. American life-insurance companies with a presence in Japan also declined.