Wilshere faces potential punishment from his club after being caught with a cigarette, although Wenger stressed no action has been taken, per David Kent of the Daily Mail:
I disagree completely with that behaviour. I need to have a chat with him about that.
You don't do what damages your health as a footballer. You damage your reputation when you do that in public.
I don't know what happened so I can't talk about any punishment.
UPDATE: Friday, Oct. 4, at 1:15 p.m. BST
Wilshere has since responded by tweeting:
---End of Update---
Wilshere’s place in the Arsenal team has come under threat in recent weeks due to the fine form of his fellow midfielders.
Mathieu Flamini arrived for free during the summer and has instantly added bite and defensive discipline as the anchor of Arsenal’s central trio in midfield.
Mesut Ozil has enjoyed a sensational start to his Emirates Stadium career, already supplying three league assists, in addition to scoring a beauty in the midweek Champions League win over Napoli.
Meanwhile, Aaron Ramsey is one of the club's top scorers in the league with four goals, leaving little room for Wilshere in the starting XI when everybody is fit.
Wenger still has Santi Cazorla, Abou Diaby, Alex Oxlade-Chamberlain, Theo Walcott and Lukas Podolski to return to his team, so pictures of Wilshere smoking will not aid the England international’s chances.
The Arsenal boss warned his young star to change his ways, but did insist his future remains at he club:
I travelled as a football player...after games in France where you didn't see each other, there was so much smoke on the coach. Everybody smoked, but times have changed...the role models from the football players request has changed as well.
He is a very important player here. ... All my plans for the future at the club have always been built with Jack and around Jack.
Arguably the figurehead of English football's future, Wilshere's decision to jeopardise his physical fitness provides a shocking sight.
In decades gone by, footballers were able to drink and smoke while still maintaining form at the highest level. Arsenal legend Tony Adams has been extremely public about his past alcohol problems in his book Addicted, per Paul Hayward of the Daily Telegraph.
However, modern-day football is a different proposition. Today's crop of players are athletes—one only has to look at the specimen of Cristiano Ronaldo to appreciate how carefully individuals must treat their bodies.
By smoking, Wilshere is endangering his aerobic capacity, not to mention his life. He looked leggy in England's recent 0-0 draw in Ukraine and required rest during Arsenal's win over Napoli.
Wenger, a known student not only of football but of the science behind it, will likely be left aghast by Wilshere's actions.
Official punishment is likely to be kept behind closed doors, but smoking is certainly not going to help him prove to his Arsenal or England boss that he deserves a starting place.