Summary
Sounds were detected under many, but not all of the orange trees sampled.
The best location for detection was directly under the root crown.
When it was possible to dig up the tree, we found Diaprepes grubs, and frequently other insects, under the crowns of trees with sounds.
Notes:
Most of the trees, particularly at Adjuntas, had more than one Diaprepes lodged under the crown. The obviously stressed trees tended to have more grubs than the healthy looking ones.
We encountered unexpectedly high levels of background noise, particularly at Adjuntas.