I am curious as to wether the two previously mentioned techniques (Sage Mode and Nine Tails Chakra More) could circumvent Zetsu's Mayfly technique?
Zetsu's Mayfly technique is stated to: "...presence is completely concealed, making it almost impossible to detect him, even for sensor type ninja like Karin."
Sage Mode affords the user heightened sensing abilities: this may just mean that it affords the user top-tier sensor-nin level sensing abilities or something along a similar lines.
Nine Tails Chakra Mode on the other hand affords Naruto Negative Emotion Sensing, which can sense negative emotions regardless of distance or obstruction. Since he could tell the difference between a disguised Zetsu and the real person, it could be assumed that his sensing abilities are beyond that of what a sensor-nin is capabable of.
well to be honest most sensor use some kind of chakra signatures to detect a person whereas Ninetails chakra mode enables sense of an emotion so if BZ has some ill intent he should be easily detected by naruto......
I believe if Naruto uses SM he cannot sense BZ since BZ was able to attack TTJ madara from blindspot.....
And yes I think it would be safe to assume that naruto's sensing abilities are beyond other sensor since he can sense an emotion rather than some random chakra signature which can be easily hidden.
In Sage Mode Naruto's sensing abilities are rather high, but not quite at Karin's level; if Karin can't sense Zetsu when it's using Mayfly, then Naruto can't do it as well. With Kurama's chakra he senses negative emotions, so he can detect Zetsu quite easily.