Thank you for your report! This is not a Japanese beetle larva, which do feed on the roots of plants but not on pine tree roots (they are destructive turf pests). This is the larva of a woodborer, but the image doesn't show features needed for a specific identification. Most of our woodborers do not attack healthy trees; the cause of tree decline is usually environmental stress (e.g. drought stress), the woodborers move in afterwords.

Tom Valente
Dec. 18, 2025, 3:51 p.m.