The nation’s major ports suffered the full economic impact of the coronavirus in March as global trade practically came to a halt. Officials with the American Association of Port Authorities say demand is virtually nonexistent. A-A-P-A Chief Executive Chris Connor estimated a 20 percent drop in volume for the big container ports. The nation’s busiest facility, the Port of Los Angeles, saw volume for industry-standard 20-foot-equivalent containers plummet 30.9 percent, to 449,568 from 650,977 the previous March. Cargo volume for the first quarter was down 18.5 percent year-over-year.