Master Gardener Practice Exam

A lesion on a stem, branch, or twig is called what?

Root Knot Blight Die Back Canker

Correct Answer:

Canker

Explanation:

A lesion on a stem, branch, or twig is called canker. A canker is a localized area of dead tissue in the bark and underlying wood, often sunken and discolored, that forms where a pathogen or injury disrupts the tissue beneath the bark. Over time, the canker can enlarge and may girdle the branch, causing dieback beyond the lesion. This helps distinguish it from other terms: root knot refers to galls on roots, blight describes rapid, widespread tissue death often affecting leaves or large areas of the plant, and dieback describes progressive death starting at the tips of shoots rather than a discrete patch on the stem.

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