When pruning my roses a few weeks ago, I noticed several canes were hollowed out. You describe the damage caused by the raspberry horntail common in California, but only causing damage in the warm interior valleys. Wasplike adults insert their eggs about 2 inches below cane tips. When eggs hatch, the worms feed spirally down canes and eventually develop into 1-inch segmented caterpillars. The larvae spend the winter in the canes then pupate in the spring.
Adults emerge through a round hole cut in the sides of the canes.
There is only one generation per year. Look for egg laying incisions, swellings caused by larvae or wilted tips and cut them off below the infestation. Q. The gravel driveway to my country home is lined with 7-year old Raywood ash trees. Last summer I noticed that two trees had some dead limbs and branches. A. Raywood ash trees in Northern California and the Central Valley have been suffering from a couple of problems.