Almond trees are closely related to, and even resemble in shape, peach trees and are prone the same diseases. In Texas, almond trees do not fare as well as other fruit trees. Early bloomers, the trees often suffer frost damage in the spring. The key is to plant later blooming varieties.
Brown rot is caused by a fungus that produces spores, which are carried by wind or insects, according to the "Encyclopedia of Gardening" by the American Horticultural Society. Parts of the tree affected include the tree's flowers, shoots and fruit buds. The flowers are affected first, especially when they are fully developed. After killing the flower, the fungus then moves to the stems, twigs and branches of the tree. A canker forms, becoming larger until it kills the branch. Brown rot can also affect the shell of the almond, killing the nut. Treatment includes application of fungicide beginning with the budding of the flowers and continuing regularly until the flowers are fully open.
Bacterial Leaf Spot
Almond trees in Texas are affected by bacterial leaf spot, according to Texas A&M University. Bacterial leaf spot is caused by a bacteria that attacks the tree during rainy, cool weather. Symptoms includes angular-shaped dark spots and patches on the leaves that appear water soaked and have yellow edges. Spots join together and kill the leaves, causing them to drop off the tree early, usually in mid-summer. Prevention is key to controlling bacterial leaf spot. Prune, remove and destroy affected branches. Fertilize and water the tree on a regular schedule, keeping it as healthy as possible.
Almond trees suffer from leaf curl like their cousin, the peach tree. Leaf curl is caused by the fungus, Taphrina deformans, which thrives and multiplies in cool, wet conditions. The symptoms include newly budding leaves that become distorted, blistered and swollen, according to “Pests and Disease” by Richard H. Cravens. The leaves turn yellow or pale green, wither and fall off the tree early. The leaves are often covered in a coating of multiplying spores. Prevention includes spraying the tree in mid- to late-winter with a copper-based fungicide, repeating the process two weeks later. Or apply ferbam after the leaves drop in the fall and again in the spring before the leaves form. If the tree is affected, remove leaves before they turn white.