Galls are plant tumors they have been known since mythical and biblical times. Galls are neoplastic growths resulting from the reactions of plant species to various kinds of stimuli. Diverse species of insects which infect plant tissues to spend a part of their life cycle cause gall formation. Gall morphogenesis is the result of interaction between morphogenetic control of the plant body and the insect factor (Miles ,1968). Thus, the galls are unique examples of complex interactions and mutual adaptation between the host and pathogen caused by cellular hypertrophy and hyperplasy. Galls are pathologically developed cells, tissues or organs of plants that have risen mostly by hypertrophy and hyperplasy under the influence of parasitic organisms like bacteria, viruses, fungi, nematodes, mites or insects.

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Keywords: Galls, Neoplastic, Hypertrophy, Hyperplasy.