Goals from Horsfall, Hoskins and Ashley-Seal mean the home side take all three points.
Colchester United slipped to defeat at fourth-placed Northampton Town.
Fraser Horsfall got the home side off to a good start with a goal inside the opening fifteen minutes, heading home from a corner.
But Jon Brady's side would have to wait until the second half to add to their tally, with Hoskins curling in a good effort, turning provider for the third in injury time, cutting the ball back to Benny Ashley-Seal to ensure three points stayed in Northampton Town.
Wayne Brown named a line up with one change from the side that started against Carlisle United at the JobServe Community Stadium seven days ago, with Brendan Wiredu dropping to the bench as Emyr Huws took his place.
There were welcome additions to the bench for the U's with Noah Chilvers and Tom Dallison both returning from injury, taking their places among the substitues along with the scorer of the second from last weekend, Tyreik Wright.
The first five minutes of the game brought challenges for Wayne Brown's side who fought to stay level in the opening exchanges. Sam Hornby was forced into a fine save after Sam Hoskins had turned the ball goalwards from Mitchell Pinnock, with another shout of handball in the area from the Cobblers' players, but the U's were able stay on level terms despite the early scare.
But the hosts didn't take long in finding an opener, with Jon Brady's side getting the opening goal on the quarter hour mark. Fraser Horsfall, the Cobblers' captain and third highest scorer was on target to nod home at the back post from Pinnock's corner, putting the ball in the opposite corner.
Jon Brady's side were able to keep the pressure on the U's for much of the first half, with Colchester United struggling to test Liam Roberts in the home goal.
The Cobblers were winning corners on a regular basis, with Pinnock's delivery causing trouble in Sam Hornby's box. One such corner fell to Fraser Horsfall again, who was unlucky to see his goalbound header cleared off the line by Cole Skuse.
The hosts took a desevred lead in at the break, with the U's needing a big performance in the second half to get anything from the game.
But the U's found themselves two goals down just three minutes after the restart and it was Sam Hoskins on target for the hosts this time. The Cobblers moved the ball quickly upfield with Magloire driving at the defence and shifting it to Lewis who quickly played it out to Hoskins, who curled it beyond Hornby and into the corner of the net.
Hoskins could have had his second, and Northampton Town's third of the game ten minutes later, when Lewis' ball looped over the U's defence. The Cobblers' striker just had Hornby to beat, but lifted his effort well over the bar and out of danger for the visitors.
With fifteen minutes left on the clock, the U's went close to getting at least one goal back with two good chances from Judge's corner. The first saw a mis-hit clearance back across his own six-yard area by Aaron McGowan, before the ball fell to Judge who struck the woodwork with a low drive.
And Judge went close again a couple of minutes later, with another low curling effort from the edge of the penalty area, this time shooting just wide of the mark with the ball taking a deflection off a home man in the process.
Northampton Town added a third late on with Hoskins cutting the ball back to Ashley-Seal to tap in, rounding off a good afternoon for the hosts.
The defeat means the U's stay in twenty-first, with a home game against Hartlepool United coming up on Tuesday evening.
Northampton Town starting XI: Roberts, McGowan (Rose 79'), Sowerby (Lubala 72'), Guthrie, Horsfall, Hoskins, Lewis, Pinnock, Koiki, Magloire, Appere (Ashley-Seal 81').
Unused subs: Harriman, Pollock, Mills, Maxted.
Colchester United starting XI: Hornby, Chambers, Smith, Skuse, Judge, Sears (Wright 82'), Edwards, Kenlock, Eastman (Andrews 60'), Tchamadeu, Huws (Chilvers 70').
Unused subs: George, Wiredu, Dallison, Coxe.