Speaking at the announcement Newcastles Academy squad for next season, Fletcher said: Its a great honour for the lads to represent their countries in a World Cup, at whatever level.
All five of them have a lot of potential, and were unlucky not to have more of our squad there, with injuries damaging the chances of Andy Buist, Ed Williamson, Stuart Mackie and Stuart Walker.
Scrum half Dickson was last week named Falcons academy player of the season after making his first team debut and captaining the Development Team to three Sevens titles in the Radio Borders Kings of the Sevens competition in Scotland.
Ahead of departure for the World Cup, the 20-year-old said: Im looking forward to going away to Argentina and coming back for a good pre-season.
We meet up with the rest of the England squad on June 1 at Twickenham, train for two days and then fly to South America. The first match is against Samoa on June 6, and we know that wont be an easy one.
After a successful campaign with the academy this year, he said: I set goals at the start of last season, and while Ive been happy to achieve quite a few of them I know I still have a way to go, so Peter Walton and John Fletcher at the club have been really good in helping me focus on where I need to get to.
I know that I have to be as involved as I can be when Im with the first team - just be myself, be aggressive, get on with my game and hopefully the rewards will come.
The major goal is to push James Grindal and Hall Charlton for a place in the first teams match-day 22, and Im working hard towards that at the moment.
Centre Dehaty forms part of the World Cup squad after a consistent season in the Development Team midfield, and having worked a lot on his game to secure his place on the tour party, said: Ive trained hard with the academy and weve played some decent games this season, but the aim is obviously to train with the first team and improve from there in the next year.
The Newcastle local lad attended Dame Allans School in the city and joined the Falcons as a youngster, before the club sent him to New Zealand for a year to aid his development.
The Falcons helped me to go to New Zealand for the 2003/4 season as part of the programme sponsored by the 500 Club lottery, so I played a year with the Mahurangi Club in North Harbour which has toughened me up a lot.
I was working a manual job from 7.30am until 5pm every day as well as training and playing rugby, which was just what was needed to be honest. We were doing everything out there farming, building fences, just whatever we could get our hands on to in order to build ourselves up.
Dehaty, too, made his first team bow in the season just finished, coming on as a replacement in the home win over three-time Premiership champions London Wasps.
When I started training with the first team it was a lot harder than anything Id done before, and then to go into the game against Wasps, who were European and English champions at the time, was a great experience, he said.
It was extremely tough having guys like Ayoola Erinle running in my channel, theres no denying that, but I know what its all about now and it means I can prepare myself well if and when I get another chance at that level.
In the meantime Im just concentrating on doing the best I can in the Under-21 World Cup and for the Falcons Academy team.