Giant Growth should replace Might of Old Krosa with Giant Growth . Much more versatile, much less predictable. Better in every way.

@ catcherinbaseball: i can see your point and i believe it might be not too bad, however i made the experience that i usually run out of cards very fast and Burning-Tree Emissary is actually not that big thread, i mean comming as a 2/2 for zero mana is good but without any evasion he is likely to do nothing for me.
While you are right that Revenge of the Hunted is unlikely to be drawn during the very early turns, in fact it can be drawn and trust me this card is changing the board situation everytime i play it, furthermore i like to have some kind of s.o.s. card, when i need a topdeck at some point in the game.

@ Kittacus: i will look into that for sure, just realized Might of Old Krosa is still a leftover from the earlier Wild Beastmaster deck

This deck, except for its creature base, looks exactly like a pump infect deck. If you removed two Wild Defiance to add 2 more Mutagenic Growth and removed your current creature base for Glistener Elf , Blight Mamba , and Ichorclaw Myr , then you have the capacity to win games on turn 2. Moreover, playing infect, you won't have to worry about the damage fading away over time due to life-gain and you'll only need to hit for half as much. Keep the Might of Old Krosa by the way and add in Groundswell as well if you can...the idea is to get more damage in faster.

I think you might have better luck with a more tempo style with green. Thrun, the Last Troll and Aether Vial would fit nicely into this deck. Another nice card to play around with would be Birthing Pod. I think what you're trying to do with the Vines of Vastwood, Mutagenic Growth, Phytoburst, infect already does it better.

Burning-Tree Emissary + Talara's Battalion is a great combo.