What are sugar streaks in hard maple?

What are sugar streaks in hard maple?

• A. Large dark lines caused by fungal staining.
• B. Narrow brown-colored marks about 1/4 to 1 inch long caused by cambium miners.
• C. Broad yellow bands indicating stain from metal exposure.
• D. Short white patches due to insect feeding.

Answer: (B)

Sugar streaks are thin, linear discolorations produced when insects called cambium miners tunnel in the cambial layer of hard maple. The larvae create narrow brown marks that run along the grain, typically about a quarter inch to an inch long. This pattern and size distinguish them from other wood discolorations: fungal staining tends to form larger, irregular dark lines; metal exposure causes broad yellow bands; insect feeding can produce patches or holes. So the narrow brown marks from cambium miners best explain sugar streaks.

Sugar streaks are thin, linear discolorations produced when insects called cambium miners tunnel in the cambial layer of hard maple. The larvae create narrow brown marks that run along the grain, typically about a quarter inch to an inch long. This pattern and size distinguish them from other wood discolorations: fungal staining tends to form larger, irregular dark lines; metal exposure causes broad yellow bands; insect feeding can produce patches or holes. So the narrow brown marks from cambium miners best explain sugar streaks.