Warwick

From personal experience seems to be the absolute worst experience for poppy jungle, his early game is insane against yours, he can easily invade you when you're low. Your W will not stop his R & Q. One good thing that you can do though is make him leave with your R during a team fight or even charge him off of your back-line if necessary.

Graves

Theoretically a extremely easy matchup, your out damage him when even or ahead, and can easily kill him very early on in levels 2-4, however it seems to be one of those champions that awlays have a team that'll collapse the second you have a chance to kill him and are always watching his back, if they help him get ahead he'll really become a problem for you.

Hecarim

Same as warwick, you cannot stop his bloody R and his E doesn't seem to be affected either. He'll constantly invade your precious jungle and be quicker to gank early game, but if you manage to get ahead with the help of proper teamwork you can outscale him where he'll be unable to do what hecarims do mid-lategame.

Shaco

Constantly invades, difficult to duel, but in the right circumstances you can out damage him easily. Ward up and maybe even take a ghost poro.

Lee Sin

Can disrupt his, but they're so often and so variable that it can be difficult to keep him down. Dueling potential is also slightly out of your favor.

Xin Zhao

Early too Mid game it is possible to catch him out and kill him with little danger from himself, but if heas able to get ahead or to late game he can just auto-attack you to death.

Kayn

Another case where if not terribly behind, its pretty easy to out-duel Scythe-thing and his human slave. Also he loves to dash both before his ult and after it, so just mess his groove up.

Evelynn

Cannot remember last time I had this matchup but you are able to interrupt her E

Amumu

Can just deny their Q, They'll also do insignificant damage if you have a Adaptive Helmet.

Nocturne

Difficult to out damage, cannot W anything from them. Hard to prevent invading while alone. They can do their entire engage on your carry while you're unable to stop it.

Kayle

Easily burstable since she shouldn't be able to ult herself while cc'd, you can also just make the invulnerable target leave the area with the big wacky hammer.

Udyr

Easily beatable unless several behind, has nothing to easily reach your backline.

Zac

Hard to kill, you shouldn't even be trying to fight him alone anyways. Just stop his Slingshot and watchout for his Q since he can throw it at you and just auto a nearby minion after.

Vi

Difficult to out-damage, but you are easily able to make her engage very difficult.

Maokai

No Experience. Cannot remember last time.

Nunu & Willump

No Experience.

Kindred

One great thing about Kindred is you can interrupt her Q easily with how often its used which is likely to give opportunity to combo. Also get it or it's team out of the budget Taric ult extremely easily.

Kha'Zix

A fed kha'zix is a pain with his ult, but if you're even remotely close to him in power then you can just shut down all his attempts, especially if you're ahead. Squish the bug.

Rengar

Just like Kha'zix and Monkey boy you can just prevent his engage, and at the same time easily kill him throughout the entire game if he is not fed ahead.

Nidalee

Use your superior movement speed to get close while dodging her spear, you'll then likely be able to tear away most of her hp. You can also keep her away from your carry easily.

Diana

No Experience. Cannot remember last time.

Elise

No Experience. Cannot remember last time.

Jax

Same story as Xin except he can stop your autos, which also means your proc burst.

Shyvana

Wukong

If you know he wants to ambush your hyper carry you can prevent his entire engage by just standing by the carry. W him if he tries to go in then charge or ult him away.

Volibear

Nope run, you will not be able to duel a Volibear, ideally Ult him away with his strongest teammate in a team-fight and help your team mop up the rest.

Teemo

Win super hard early game, his blind can only prevent one source of your burst. Save your auto and all its procs for after blind wears off or while heas stunned and melt his face off.

Jarvan IV

Be careful with dueling, he can shred your armor wish his Q and he has a burst. You'll be able to stop his Dash from chasing, escaping, and even over walls but his Ult is unstoppable sadly.

Ivern

I still cannot imagine how Ivern would be the deciding factor to being able to win.

Yorick

Easily outdamagable after early game, his circle wall can be used with your E and your W stops his zombies from jumping too you.

Twitch

It shouldn't be possible to lose to this unless your team drops the ball and the enemy team steals that same ball to then give it too Twitch as fuel for lategame.