WW flag leaf marks

[SimonD]

anybody know what's causing these horizontal marks on the flag leaf?

 

[willy]

Mag deficiency

 

[blackwater boy]

A few years ago in Ireland all the flag leaves were like that, it became known as the craic!! A farmer was out spraying one day and his neighbour asked him what he was spraying for and he replied "for the craic"... Think it happens when the flag leaf is coming out and the weather is cold and harsh or very hot and the ligule of the plant squeezes very tight to defend itself and causes the squeeze mark.

 

[Rob Holmes]

Yeah, some of our Santiago has it, my agronomist says it was a cold snap when flag was coming out