Hass Avocado Tree Leaves Are Shriveling

Heat

• Heat stress may cause the leaves of a Hass avocado tree to shrivel. Haas avocado does best at temperatures between 60 and 85 degrees Fahrenheit. It can tolerate temperatures as low as 26 F but may experience damage or die in extreme heat. Provide young Hass avocado trees with shade in areas where the temperatures rise above 90 F in the afternoon. Even with shade, however, Haas avocado may not survive the heat in some regions.

Disease

• Diseases may make the leaves of the Haas avocado change appearance. Sun Blotch, for instance, is a viral disease that causes mottling and crinkling of new leaves as well as deformation of fruit. Laurel wilt, which is prevalent in some areas of Florida, causes the leaves of affected trees to droop and become discolored. The avocado tree may drop its leaves soon after wilting. Consult your county Cooperative Extension Service for advice regarding diseases of avocado in your area.

Freeze Damage

• Haas avocado leaves may appear wilted or flaccid during periods of freezing temperatures. That appearance does not mean the leaves are or were frozen; frozen leaves are firm and brittle and may collapse. Haas avocado is hardy to 26 F, but its leaves may freeze at 30 F. Protect the tree with covers, such as rugs, blankets or towels, during cold snaps. Heat from incandescent lamps or camp lanterns provides additional protection.

Improper Watering

• When a Hass avocado tree is overwatered, it may develop curled leaves. When underwatered, the tree wilts and develops dried leaves. Water the tree to keep its soil evenly moist. Mature avocado trees require about 20 gallons of water each day during the growing season, while seedlings and young trees require much less water. Newly planted trees, for instance, require about 2 gallons of water daily. Check the soil before watering; allow it to dry slightly between watering times.