Crown gall disease caused by Agrobacterium tumefaciens the most common and serious disease of almond rootstocks and almond trees in general is described. The behaviour of some almond rootstocks to infection by the crown gall pathogen and the possibility of applying the biological control method in the nursery practice in order to control the disease and its limitations is discussed. Hyperplastic bacterial canker of almond caused by Pseudomonas amygdali is described. Phony peach, almond leaf scorch and plum leaf scald diseases caused by the xylem limited fastidious bacterium Xylella fastidiosa are briefly presented.