Hagerstown honored Moss this weekend for his 50 years of service as league president. It was the fifth stop of Moss' 16-city retirement tour.
Suns starter Colton Willems (4-4) held his own through the first five innings, protecting a 1-0 lead until the hinges on the defense started to come off.
Jason White opened Delmarva's sixth inning with a single to right. White took off on a pitch and headed to third when Matt Angle served it into short right-center field.
Suns right fielder Michael Burgess made the scoop and threw wildly to third in an attempt to gun down White. White scored on the error and Angle took second. One out later, Joe Nowicki singled home Angle for a 2-1 lead.
"When you get the ball, you gotta know what you are going to do with it," Coles said. "We did that a couple of times tonight. We've got to play better defense."
If there was any need for proof, it came in the seventh inning.
Delmarva (32-24) led off by loading the bases against Willems, bringing White to the plate against a drawn-in infield. White hit a high-bouncing grounder to Lyons at short, who took his eye off the ball as it ticked off his glove for a two-run error.
Willems was lifted for Dan Leatherman, who was greeted by a sacrifice bunt by Angle, setting up Nowicki's fly ball that left fielder Boomer Whiting lost in the twilight sky for a two-run double and a 6-1 lead.
Delmarva closed the scoring in the eighth with an RBI triple by Kieron Pope, who scored on Victory Castillo's sacrifice fly.
Seuss led off the second with his first homer, the only run Hagerstown scored off Delmavra starter Zach Britton (5-4). Britton went six innings, allowing three hits while striking out three.
Seuss hit his eight homer of the season in the seventh off reliever Brian Parker.
Nowicki finished with three hits and three RBIs for Delmarva.
"Colton has thrown well the last couple of games," Coles said. "We've still got to make plays. It's not time to get excited. We still have 15 games left in the first half and eight of them are against (first-place) Lake County. We aren't out of it yet, but we just have to be calm and play the team that is in front of us."