I was doing some scouting on the farm and came across this (lines on the leaves) is it a disease? How can it be treated?

Good morning farmers, I was doing some scouting on the farm and came across this (lines on the leaves) is it a disease? How can it be treated? 
Secondly the plants appear yellowish yet I think they should be green, what should I apply? Waiting for your guidance
 

 
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