Which term describes an abnormal swelling of plant tissue caused by microorganisms or insects?

The term that describes an abnormal swelling of plant tissue caused by microorganisms or insects is "gall." Galls are abnormal growths formed on plants as a response to the presence of certain pathogens, such as fungi, bacteria, or insects. These organisms induce the plant to grow excess tissue, leading to the characteristic swelling or growths on leaves, stems, or roots.

The involvement of insects, such as gall wasps, is particularly notable since these insects lay their eggs in the plant tissue, prompting the plant to form galls as a protective response. Understanding galls is important for pest management and plant health because they can sometimes lead to other secondary infections or affect the overall vigor of the plant.

The other terms refer to different plant issues: blight describes a rapid and extensive death of plant tissues, usually caused by disease, chlorosis indicates yellowing of plant tissue often due to nutrient deficiencies, and necrosis refers to the death of cells or tissue in a plant. Recognizing these distinctions is essential for effective diagnosis and treatment in plant health management.