Lower Limb Dieback In Almonds

By Patrick Cavanaugh

Themis Michailides, Ph.D, a UC Davis plant pathologist based at the Kearney Ag Center in Parlier reported on Lower Limb Dieback (LLDB) in almonds at the recent Almond Industry conference in Modesto. He said he initial symptoms are the yellowing of leaves on the lower limbs and that there is still not a known cause of the disorder, which can cause death to the limb.

Michailides has surveyed orchards with dieback symptoms and found that two different species of fungi were found on the affected limbs---Phomopsis and Botryosphaeria. However, the same fungi were also found in healthy limbs, suggesting that they are not involved in causing LLDB.

Researchers are looking at different species of Botryosphaeria, which could be more virulent and capable of causing dieback. They are also looking into whether or not herbicide drift may be causing LLDB. At this time it is suggested that growers prune off the limbs with LLDB symptoms.