My young apple and grape shoots have small leaves bunched in a rosette, is this zinc (little leaf)?

Small, narrow leaves crowded into a rosette at the shoot tip with very short spacing between leaves and poor shoot growth is the classic little leaf or rosette symptom of zinc deficiency in fruit trees like apple, grape and citrus. Zinc is needed for the hormone that elongates the stem, so when it is short the internodes stay short and the leaves bunch up and stay small, and you may also see interveinal yellowing on those small leaves. It is common on high pH, sandy and eroded soils and where heavy phosphorus has been used. Please confirm with a leaf or soil test before treating, since rosetting can also be confused with certain virus diseases or pruning and frost effects. The standard correction in orchards is foliar zinc sulphate sprays timed to the new flush, often a low concentration like around 0.5 percent, repeated as advised, because trees respond well to foliar zinc, plus soil zinc sulphate where the soil test calls for it. Adjust the product, concentration and timing to your leaf test and local horticulture or KVK advice and do not over-apply, because zinc can build up to toxic levels.