My peach tree suffered much from pest and diseases this season. Due to the prolonged period of rains, the tree suffered much from leaf curl (Taphrina deformans). Now there are galls on the twigs (see picture). The nature of these galls are unknown to me...if you know what they are please let me know. They look like dark brown shiny beads with starch-like substance inside. I have been doing research to identify them but I guess the most scientific step would have been to submit samples for pathological analysis. It is my guess that these are caused by the fungal damage from the leaf curl.
Plant galls are not uncommon. They are likened to a tumor that results from abnormal cell growth due to irritation caused by insect infestation and fungal or bacterial infection. They grow on different plant tissues such as the roots, stems, branches, fruits and leaves. The nature of the gall is not only affected by the organism that is causing it but also the location of gall formation on the plant. Galls growing on leaves tend to be softer than those growing on bark of trees. Galls growing on hairy leaves tend to be fuzzy while those growing on the branches are hard and shiny (such as the ones in the picture).
Although they look very severe, galls are not detrimental to the plant. They can interfere with the growth of the particular part where they are growing but not the whole plant.
Since I am not sure of the true nature of these galls, I thought of removing them by hand to avoid further proliferation. Luckily they were concentrated in a couple of branches only.