Trees affected with bunch disease show the bunching symptom, which is due to excessive growth of slender succulent twigs from lateral buds that normally remain dormant. In moderately affected trees one or several branches will show the “bunch” growth symptom. Bunching in severely affected trees may involve all main branches which produce thick masses of sucker-like growth and few, if any, nuts. Observations indicate that the Stuart variety is the most resistant to bunch disease. [Illustration: Figure 4. Rosette die-back symptoms of pecan tree showing severe zinc deficiency.] _Control._—There is no known effective control for bunch disease. Early detection of the first symptom of bunch and pruning out of the affected branch may prevent spread of the disease throughout the tree. When the tree is severely affected, and limbs are involved, the tree should be destroyed to protect nearby healthy trees from infection. For propagation purposes, all bud or scion wood should be taken only from bunch disease-free trees. ROSETTE Rosette is a nutritional deficiency disease caused by certain soil conditions which make zinc unavailable to the pecan tree. All pecan trees require zinc for growth. Trees showing the first symptom of zinc deficiency have yellowed tops. The individual leaflets when examined are yellowish and mottled. The next season the foliage may be yellowish and the leaflets narrowed and crinkled. More severely affected trees produce foliage which is a yellowish to reddish-brown overall color, and the leaflets are very narrow with reddish-brown spots and may be perforated. Shoots are much shortened and the leaves are produced in compact bunches of dense foliage. Trees affected by rosette for several seasons have many dead shoots and small branches from the dying-back of each season’s growth, Figure 4. Such trees are greatly stunted, of poor vigor and produce few, if any, nuts. _Control._—Rosette is controlled readily by applying zinc sulfate to the tree either as a foliage spray or in the dry form as a soil application. Where a disease and insect spray control program is being carried out, zinc sulfate may be added to the spray mixture. Foliage spray. Two pounds zinc sulfate (36 percent) per 100 gallons of water. First application: after pollination when tips of nutlets turn brown. Second application: 3 to 4 weeks later. Third application: 3 to 4 weeks later. Soil application. Application of zinc sulfate to the soil, particularly in a large orchard is a more expensive operation, but it provides longer protection against rosette. In highly alkaline soils, or soils that readily fix zinc and make it unavailable to the tree, foliage spray applications of zinc sulfate are more economical because of the excessive rates required to supply available zinc through the soil.