I've taken in clones with red assed root aphids... didnt know it immediately... the cat I got the cut from started sayin he got fungus gnats from me in the trade (possible, I dont consider them pests) but when I went to his grow, it took me 2/10ths of a second to notice their rounded bulbous asses and long wings extending past that fat round ass so I knew immediately they were flying aphids... went home and saw a crawler in my veg box.... I never saw anything else... the roves got em....
I got a similar story about onion bulb mites...
for me, rove beetles are a mandatory part of my grow's "immune stsyem"
pimp, that looks like a mutation as opposed to insects... No serrations usually means photoperiod stress, but that looks like a mutation to me... generally grasshoppers and the like leave noticeable divots or chunks missing... I'm not aware of anything that goes smoothly along the edge of a leaf eating straight lines ... I'm leaning toward mutation in the leaves... I have seen a cleaner version of no serration mutation, but that was a whole plant doing it uniformly... yours looks like a stress mutation... but if it is a mutation, I dont think theres much to fix....
View attachment 532634
If you believe it is damage from grasshoppers, you might think to try a parasite like Nosema locustae...
http://www.planetnatural.com/product/semaspore-grasshopper-control/