Magnesium deficiency is rare in California stone fruit orchards. Symptoms include a "V" shaped chlorotic area at the apical end of leaves. Irregular necrotic areas along the margin of leaves can also develop. We were able to induce mild deficiency symptoms in the sand tank study, but a survey of commercial orchards found none close to deficient. If the mid summer leaf level drops to 0.25% Mg, correction can be easily achieved with any Mg containing fertilizer applied to the soil.