It is often hard to diagnose a micronutrient deficiency in the field as often a crop may be struggling with a deficiency before symptoms are visible.
If you suspect a micronutrient deficiency the Yara CheckIT app or the deficiency webpages within each crop section on this site can be used to compare any symptoms with libraries of deficiency photographs.
The only certain way to diagnose or confirm a micronutrient deficiency is to send a tissue sample for laboratory analysis. Yara Analytical Services offer a full range of soil, leaf, petiole fruit and water analyses and if needed can also offer a 24 hour service for tissue analysis.