Almond trees are lovely in a landscape and they can produce up to 65 pounds of almonds a year. As far as fruit and nut trees go, almonds have shown themselves to this gardener to be trouble free, but problems can happen. One of those problems is called almond leaf scorch.
Almond leaf scorch is caused by the same bacteria (Xylella fastidiosa) that causes Pierce’s disease, in grapevines, and alfalfa dwarf disease. This disease can also infect many common weeds, including annual bluegrass, burclover, cheeseweed, chickweed, filaree, London rocket, and shepherd’s purse. This pathogen is found on many familiar plants, such as bermudagrass, blackberries, elderberries, fescue grasses, nettle, and rye, without causing any problems for the host plants.
How almond leaf scorch spreads
This disease is carried by sap-sucking insects, such as leafhoppers, sharpshooters, and spittlebugs. As they feed, the bacteria moves from the insect into the plant’s xylem, where it begins to reproduce.
Almond leaves are normally a lovely green color. Around June, however, you may notice the edges (margins) of leaves look scorched. If you look closely, you will see a yellow band between the scorched portion and healthy leaf tissue. This scorched appearance looks a lot like salt burn, but salt burn lacks the yellow band.
This disease is normally seen on one branch, or one scaffold of branches. Scaffolds are major horizontal branches. Over time, this disease spreads to the rest of the tree. Another name for almond leaf scorch is golden death. While infected trees can live for several years, they will leaf out later and be far less productive than a healthy tree.
Leaf scorch management
If your beloved almond tree becomes infected, early detection is critical. The infected branch, or its scaffold, should be removed 5 to 10 FEET below any visible symptoms. Keep a close watch to see if any signs of infection appear elsewhere on the tree. If the tree is less than 10 years old, your best bet is simply to replace the tree.
I hope that your almond tree never faces this problem, but now you know what to watch for.
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