Pencil points to the location where the cane borer drilled a hole into the red currant stem.
Longitudinal slice of an infested red currant stem. Cane borer larvae can be seen near the point of the pencil. The black necrotic area indicates the region of the stem that has been damaged by the larvae.
Cane borer larvae inside of a red currant stem.
Cane borer larvae removed from the red currant stem.
Cane borers lay eggs through a puncture wound in dormant currant stems. The larvae burrow up and down in the center of the currant stem during the winter dormant season. In the spring, the cane will leaf out, flower, produce fruit and then lodge over to the ground because of strong winds in spring, or because of the weight of the fruit in mid-summer. These photographs were taken in mid-January of borer larvae infesting red currants cultivated in Corvallis, Oregon. Borers seem to prefer red currants to black currants.