It will soon be ‘wrong’ to harvest from plants: 

The other day it was 25°, perfect day, on driving through town i notice something like 75% of cars had their windows up,  i could only presume and am probably wrong that they had the air con on,,ah the air conditioned eco warriors.

That old news...  In the 80s there was research that verified plants could be distressed etc.  I think it was via electrical signals or smell.