Answer :
Final answer:
Plant galls are abnormal growths on plants commonly caused by plant growth-regulating chemicals produced by insects, mites, and other arthropods or pathogens like bacteria.
Explanation:
Plant galls associated with insects and mites are caused by a variety of factors. The most common cause is the release of plant growth-regulating chemicals or stimuli by insects, mites, or other arthropods. These substances disrupt the normal plant cell growth, creating the abnormal swelling known as a gall. For example, when female gall insects lay eggs in plant tissues, the plant reacts by forming a gall, which serves as a protective environment for the developing larvae. Both the mechanical damage from larval feeding and chemicals secreted by larvae contribute to gall development. Additionally, pathogens like bacteria can also cause galls by altering plant growth regulators.
Other forms of plant damage, such as bacterial leaf spots or systemic toxemia, can be caused by different pathogens and have distinct symptoms. The identification of the causative organism is crucial for determining the appropriate control measures, which are often most effective when targeted at the immature or emerging adult stages of the pest.
