Malbec problem

[ciclope]

Malbec leaves
I am new to the forum and I send you a cordial greeting. I hope you can help me with my malbec plants. Some plants are presenting these symptoms on the leaves... someone could help me. thank you!

 

[Hazelemere]

magnesium deiciency. foliar spray with epsom salt solution or put sulpomag into the soil. I use 1 bag each year for 135 vines