Zinc deficiency symptoms are usually most obvious in the spring of last year's growth. It is characterized by small, narrow leaves, also known as little leaf, that appear similar to leaves injured by Roundup herbicide but with less cupping and crinkling and usually occurring higher up in the tree. Often, there is blind wood in the middle portion of shoots and a cluster of normal leaves at the terminal end of affected limbs known as rosetting. Interveinal chlorosis may be present on leaves. Branches will die back in severe cases. In grasses, you get striping or banding on the leaves.
The most common method for correct zinc and other nutrient problems are by foliar sprays. The preferred timing of sprays is late dormant to post bloom into early spring on tree crops when a new flush of growth is taking place.